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THE

JOURNAL OF SCIENCE,

EXHIBITING

A VIEW OF THE PROGRESS OF DISCOVERY

IN NATURAL PHILOSOPHY, CHEMISTRY, MINERALOGY, GEOLOGY, BOTANY,
ZOOLOGY, COMPARATIVE ANATOMY, PRACTICAL MECHANICS, GEOGRAPHY,
NAVIGATION, STATISTICS, ANTIQUITIES, AND THE FINE AND USEFUL ARTS.

CONDUCTED BY

DAVID BREWSTER, LL.D.

F.R.S. LOND. AND EDIN. F.S.S.A. M.R.I. A.

CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE } CORRESPONDING MEMBER OF THE ROYAl^
PRUSSIAN ACADEMY OF SCIENCES ; MEMBER OF THE ROYAL SWEDJSH ACADEMY

OP sciences; of the royal society of sciences of Denmark;

OF THE ROYAL SOCIETY OF GOTTINGEN, &C. &C.

VOL. X.
OCTOBER— APRIL.

JOHN THOMSON, EDINBURGH
AND T. CADELL, LONDON.

M.DCCC.XXIX.

itgi;

ifi"^

PKIM'ED BY JOHN STAUK, EDINBURGH.

CONTENTS

OF THE

EDINBURGH JOURNAL OF SCIENCE.
No. XIX.

Page
AlkT. I. Biographical Account of Alexander Wilson, M. D. late Profes-
sor of Practical Astronomy in Glasgow. By the late Patrick
Wilson, A. M. Professor of Practical Astronomy in the University
of Glasgow, ... - - 1

II. On the Mean Temperature of Bombay, deduced from Observations
made in 1827, &c. Communicated by Alexander Adie, Esq.
F. R.S. E. &c. - - - - - 17

in. Table of the Variations of the Magnetic Needle at Boston, Falmouth,
and Penobscot, in North America, during 128 years. By S. De
Witt, Surveyor-General, - - - - 22

IV. Account of the Quartz Crystals and the Siliceous Paste found in i\\e

Marble of Carrara, as described by M. Repetti, - - 24

V. Facts and Observations relative to the recent formation of Quartz Cry-
stals, &c. and of indurated Calcedony from Siliceous Solutions and
Pastes, - - ' - - - - 28

VI. On a remarkable Formation of Clouds. By George Harvey, Esq.
F. R. S. Lond. and Edin. F. L. S. Honorary Member of the Society
for promoting the Useful Arts of Scotland, Member of the Royal Geo-
logical Society of Cornwall, &c. &c. Communicated by the Author, 33
VII. Account of the Steam-Engines in Cornwall. By W. J. IIenwood,

Esq. F. G. S., &c. &c. Communicated by the Author, - 34

VIII. On the Electrical Properties of the Tourmaline. By M. BECauEREL. 50
IX. Account of an Ancient Vessel recently found under the old Bed of
the river Bother in Kent, and containing the bones of men and ani-
mals. In a Letter from William M'Pherson Rice, Esq. F. S. A.
late of the College of Naval Architecture at Portsmouth, addressed to
Henry Ellis, Esq. F. R. S. Secretary, - - - 56

X. On the Expansion of Vapour. By Richard Tregaskis, Esq. of

Perran, near Truro. Communicated by the Author, - 68

XI. Theorem for computing the Elastic Force of Vapour. By Richard

Tregaskis, Esq. in a Letter to the Editor, - - 72

XII. Abstract of a Meteorological Journal kept at Funchal, in the island
of Madeira, from January 1st to December 31st, 1827. By C.
HeinEken, M.D. Communicated by the Author, - - 73

XIII. Account of Two Thunder Storms which happened iu Worcestershire,

" CONTENTS. ,

Page
in which it appeared the Electrical Discharge passed from the Earth
towards the Clouds. By John Williams, Esq. Communicated
by the Author, - - - - - 81

XIV. On the Parasitic Formation of Mineral Species, depending upon Gra-
dual Changes which take place in the Interior of Minerals, while
their External Form remains the same. By William Haidinger,
Esq. F. R. S. Edin. - - - - - 86

XV, Observations and Experiments tending to demonstrate that the Gra-
nules which are discharged in the explosion of a grain of Pollen, in-
stead of being analogous to spermatic Animalcules, are not even or-
ganized Bodies. By M. Raspail, - - - 96

XVI. Note on Mr Brown's Microscopical Observations on the active Mole-

cules of organic and inorganic bodies. By M. Raspail, • 106

XVII. Physical Notes on the Bay of Naples. Communicated by the Author
No. ir. — Account of the Buried Cities of Herculaneum, Pompeii,

and Stabiae. 108

XVIII. Notice of the Performance of Steam- Engines in Cornwall for June,
July, August, and September 1828. Communicated by W.J. Hev-
wooD, Esq. F. G. S. - - - - 137

XIX. Abstract of a Meteorological Register kept at Rampoor and Kotgurh,
in January, February, and March 1822. By Captain Patrick
Gerard, of the Bengal Native Infantry. Communicated by the
Author, - - - - - - 139

XX. Account of the Rain which fell at Bo)p[ibay in June, July, August,
September, and October, from 1^17 to 1827. Communicated by
Alexander Adie, Esq. F. R. S. Edin. - - - 141

, XXI. Experiments on the penetration of Water into Bottles immersed to a
great depth in the sea, made in a Voyage from India to England.
By Charles H. Weston, Esq. In a Letter to the Editor, - 144
XXII. On a splendid Luminous Arch seen at Plymouth, Sept. 29, 1828.
By George Harvey, Esq. F. R. S. Lond. and Edin. F. L, S.,
F". G. S., &c. &c. Communicated by the Author, - - 146

XXIII. On an interesting Meteorological Phenomenon. By George Har-
vey, Esq. F. R. S. Lond. and Edin. Member of the Royal Geologi-
cal Society of Cornwall, &c. &c. Communicated by the Author, 148

XXIV. Description of Nontronite, a new Mineral discovered in the Depart-
ment of the Dordogne. By M. P. Berthier, - - li^O

XXV. Account of two remarkable Cases of Insensibility in the Eye to parti-
cular Colours, - '- - - - 153
XXVI. Farther Remarks on Self-Registering Thermometers. Communicated

by the Author, - - - - - 159

^XVII. Account of Two remarkable Rainbows, one of which inclosed the
Phenomenon of converging Solar Beams. By David Brewster,
LL. D., F. R. S. Lond. and Edin. - - - 163

XXVIII. ANA.LYSIS OF SCIENTIFIC BOOKS AND MEMOIRS, 1C4

Elements of Natural History, adapted to the present state of the
Science, containing the generic characters of nearly the whole Ani-
mal Kingdom, and descriptions of the principal species. By John
Stark, F. R. S. E. Member of the Wernerian Natural History
pocicty of Edinburgh, &c. - - - ib.

CONTENTS. in

Page

XXIX. PROCEEDINGS OF SOCIETIES, - - - 174

1. Proceedings of the Royal Society of Edinburgh, - - ib.

2. Proceedings of the Cambridge Philosophical Society, - ib.

XXX. SCIENTIFIC INTELLIGENCE, - - 175

I. NATURAL PHILOSOrHV.

Astronomy. — 1. Observations on Encke's Periodical Comet. 2. Ephemeris
of Encke's Comet continued. .3. Comet of September 1827 and September
1820. 4. Elements of the Orbit of the Planet Juno, - 175—178

Meteorology. — 5. Captain Kater's account of the Luminous Zone of the
29th September. 6. Observations on the Luminous Arch at Islay- House,
Islay. 7' Observations on the Luminous Arch near Edinburgh. 8. Notice
of the Mean Temperature of Falmouth and the vicinity. 9. Description of the
Luuiinous Arch, as seen at Perth on the 16th October. 10. Aurora Borealis
seen at Perth on the 29th October, - - - - 177 — 179

Electricity. — 11. Foerstemann's Experiments on the conducting Power of
different Fluids for Voltaic Electricity, - - - - 179

II. NATURAL history.

Mineralogy 12. Notice of the Produce of the Tin Mines of Cornwall and

Devon. 13. Of the Cornish Copper Mines. 14. Of the quantity of Metallic
Copper, the produce of the mines in Great Britain and Ireland, 180

Geology. — 15. General Summary of the Geology of India. 16. Organic Re-
mains at Clash-bennie Quarry in Forfarshire. 17. Fossil Turtle, 181 — 185

Botany, — 18. Account of the Sensitive Properties of the Stylidium gramini-

folia. 19. Singular Phenomenon in the Sensitive Plant, - 185—186

III. GENERAL SCIENCE.

20. Notice of the Saline Lake of Loonar in Berar. 21. Inflammable Gas after
boring for Salt. 22. Bequest to Science by Dr Wollaston and Mr Davies Gil-
bert. 23. Adjudication of a Royal Medal to Dr Wollaston. 24. Adjudica-
tion of a Royal Medal to M. Encke. 25. Obituary of Members of the
Royal Society of London. 26. Two Royal Medals established for the
Society of Antiquaries. 186— .187

XXXI. List of Patents granted in Scotland since September 9, 1828. 187

XXXII. Celestial Phenomena, from January 1st, to April 1st, 1829, 188

XXXIII. Summary of Meteorological Observations made at Kendal in Sep-
tember, October, and November 1828. By Mr Samuel Mar-
shall. Communicated by the Author, - - 190

XXXIV. Register of the Barometer, Thermometer, and Rain-Gage, kept at

Canaan Cottage. By Alex. Adie, Esq. F. R. S. Ed. - 192

NOTICES TO CORRESPONDENTS.

It will give us great pleasure to receive Dr Heineken's Abstract of his Meteoro-
logical Journal for 1 828.

' CONTENTS

EDINBURGH JOURNAL OF SCIENCE.
No. XX. .

Page
Art. I. Biographical Sketch of the late Dugald Stewart, Esq. F. R. SS.

Lond. and Ed. - - - - 193

II. Notice respecting the existence of Chrysolite in Obsidian, as disco-
vered by Professor Del Rio, _ _ - 206

III. Description and use of a new Gravimeter. By Don Jose Maria

BUSTAMENTE, . - - - 207

IV. Notice of the Performance of Steam- Engines in Cornwall for Octo-
ber, November, and December 1828. By W. J. Hevwood, Esq.
F. G. S., Member of the Royal Geological Society of Cornwall.
Communicated by the Author, - - - 213

V. Observations relative to the Motions of the Molecules of Bodies. By
David Brewster, LL. D. F. R. SS. London and Edinburgh, 215

VI. Remarks on the formation of Anchors. By Commander Johk

Pearse, R. N. Communicated by the Author, - 220

VII. Summary of the state of the Barometer, Thermometer, &c. in Ken-
dal, for the year 1828. By Mr Samuel Marshall. Communi-
cated by the Author, - _ , _ 222

VIII. Account of the great Congress of Philosophers at Berlin on the 18th

September 1828. Communicated by a Correspondent, - 225

IX. A Summary of Experiments recently made on the Temperature of
Mines. By W. J. Henwood, Esq. F. G. S., Member of the Royal
Geological Society of Cornwall. Communicated by the Author. 234

X. Physical Notices of the Bay of Naples. No. III. On the District of
Pausilipo and the Lago d'Agnano. By James D. Forbes, Esq.
Communicated by the Author, ... 245

XI. Abstract of the Meteorological Register for 1822, 1823, 1824, and
1825, from Observations made by the Surgeons of the Army at the
Military Posts of the United States Army. Prepared under the direc«
tion of Joseph Lovell, M. D. Surgeon-General of the United
States Army, .... 267

XII. Thermometrical Observations made at Raiatea, one of the Society
Islands, in 1822. By the Rev. L. E. Threlkeld. Communicated
by Mr Dunlop, - - . - . 280

IV CONTENTS.

Page

XIII. Notice on the Elastic Force of Vapour. By Richard Tregaskis.
Esq. Communicated by the Author, - - - 282

XIV. Description of some remarkable Nebulae and Clusters of Stars in the
Southern Hemisphere, observed at Paramatta in New South Wales.

By James Dunlop, Esq. - - - - 282

XV. Table of the Refractive Powers of several Bodies, according to the
observations of J. F. W. Herschel, Esq. V. P. R. S. &c. With
remarks by the Editor, - . - 296

XVI. Approximate places of Double Stars in the Southern Hemisphere ob-
served at Paramatta in New South Wales. By James Dunlop,
Esq. In a Letter to Sir T. Macdougal Brisbane, K. C. B.,
F. R. S. Lond. and Edin. - - - - 301

XVII. Account of an Experiment made on the composition of Oil of Cassia,
to determine the cause of its high dispersive power, by J. F. W.
Herschel, Esq. V. P. R. S. &c. &c- - ... 308

XVIII. Contributions to Physical Geography, _ - . 310

1. Account of the Eruptions of Mount ^tna. By L. Sibiond, ib.

2. Account of thei^arge Chestnut of Mount iEtna. By L. Sisiond, 314

3. Account of the Falls of Niagara, - - - 316

4. Account of a Storm in the Desert, - - 319

5. Burning Springs in America, - - - - 321
XIX. Meteorological Register kept at Kinfauns Castle, the seat of the Right

Honourable Lord Gray, - - - - 323

XX. Account of a remarkable peculiarity in the Structure of Glauberite,
which has One Axis of Double Refraction for Violet, and Two Axes
for Red Light. By David Brewster, LL. D., F. R. S. Lond.
and Edin. - - ... 325

XXI. Account of the Single Lens Microscopes of Sapphire and Diamond, ex-
ecuted by Mr A. Prit chard. Optician, London, - 327

XXII. On the Defects of the Sympiesometer, as applied to the Measurement
of Heights. By James D. Forbes, Esq. Commuricated by the Au-
thor, - - - - - - 334

XXIII. On the influence of Light on the motions of Infusoria. By R. E.
Grant, M. D., F. R. S. E., F. L. S., Professor of Zoology and
Comparative Anatomy in the University of London. Communicated

by the Author, - - - - - 346

XXIV. Farther observations on the Generation of the Virgularia MiraUlis.
By R. E. Grant, M. D., F. R. S. E., F. L. S., Professor of Zoology
and Comparative Anatomy in the University of London. Commu-
nicated by the Author, . . - . . 350

XXV. ZOOLOGICAL COLLECTIONS, - - 351

1 Observations on the Mantis Tribe, or that of the Leaf Insects. By
Dr Adam, . . - - ib.

2. Account of a Singular Species of Mollusca from the Coast of Cey-
lon. By James Calder, Esq. - - - 352

3. Experiments on the effects produced by dividing the semicircular
canals in the Ears of Birds. By M. Flourens, - 353

CONTENTS. V

Page
XXVI. HISTORY OF MECHANICAL INVENTIONS AND OF PRO-
CESSES AND MATERIALS USED IN THE FINE AND
USEFUL ARTS, .... 354

1. Description of a Differential Barometer. By the late W. Hyde
WoLLASTON, M. D. F. R. S. - - - 354

2. Account of a method of measuring the resistance of fluids to bodies
passing through them. By James Walkek, Esq. F. R. S. Edin. 355

f-; 3. On the permanent increase of Bulk in Cast-iron by successive

heatings. By James Prinsep, Esq. Assay Master of the Mint
at Benares, - _ - - 356

4. Description of a sounding-Board in Attercliffe Church, invented
by the Rev. John Blackbuen, Minister of Attercliffe-cum-Dar-

nal Sheffield. - - - - - 357

5. Account of a Process for producing a beautiful Blue Colour. By

M. Braconnot, _ - . - 358

6. Account of the Process for making Ultramarine, - 359

7. Inventions for Sharpening Blades of Knives, - - ib.

8. Description of the Pneumatic Spoon, invented by Mr Gibson, 360

XXVII. ANALYSIS OF SCIENTIFIC BOOKS AND MEMOIRS, ib.

The Natural History of several New, Popular, and , Divertmg
Living Objects for the Microscope, with the phenomena presented
by them under observation, &c. &c. Conjoined with accurate De-
scriptions of the latest improvements in the Diamond, Sapphire,
Aplanatic, and Amician Microscopes ; and instructions for manag-
ing them, &c. &c. To which is added a Tract on the newly dis-
covered Test Objects. Illustrated by very highly finished Coloured
Engravings, from Drawings of the actual living Subjects. By C.
R. Goring, M. D. and Andrew Pritchard. No. I. ib.

XXVIII. PROCEEDINGS OF SOCIETIES, - - - 362

1 . Proceedings of the Royal Society of Edinburgh, - ib.

2. Proceedings of the Society for the Encouragement of the Useful
Arts in Scotland, . - - 363

3. Proceedings of the Cambridge Philosophical Society, - 366

XXIX.. SCIENTIFIC INTELLIGENCE, - - 367

I. NATURAL PHILOSOPHY.

Astronomy — 1. Mr Dunlop's Observations on Encke's Comet, - ib.

Optics — 2. Supernumerary Rainbows, _ - . - ib.

Acoustics — 3. Velocity of Sound in the Arctic Regions by Captain Parry's

Observations, ._----_ 368

Electricity 4. On the influence of Electricity on the emanation of Odours, ib.

Galvanism — 5. M. Becquerel on the temperature of Conducting Wires, ib.

Meteorology. — 6. Mass of Meteoric Iron found in France, - ib.

II. chemistry.
7. Diamonds made artificially in France. 8. Melting point of Silver and its
alloys with Gold, _ - - - . 369—370

VI CONTENTS.

Page
III. NATURAL HISTORY.

MiNEBALOOY.— 9. Specimen of Chalcedony with a large Fluid Cavity. 10.
Analysis of Radiolite. By Professor Hunefeld. II. Analysis of Iron
sinter from Freibei^. By M. K. Kersten. 12. Analysis of Datholite
from the Harz. By Dr Du Menil. 13. Analysis of Marmolite from
New Jersey. By Mr Thomas Steel. 14. Analysis of Bismuth blende of
Breithaupt. By Professor Hunefeld. 1ft. Analysis of Leelite. By Mr
R, Mitchell, - - - - . 370—371

Geology.— 16. Conclusion of the General Summary of the Geology of India.
By James C alder, Esq. 17- M. Raspail's Discovery respecting Belem-
nites, ... . 371—376

XXX. List of Patents granted in Scotland since December 6, 1828, 376

XXXI. Celestial Phenomena, from April 1st, to July 1st, 1829, - 376
XX XI I. Summary of Meteorological Observations made at Kendal in Decem-
ber 1828, and January and February 1829. By Mr Samuel Mar-
shall, - - - - , 378

XXXIII. Register of the Barometer, Thermometer, and Rain-Gage, kept at

Canaan Cottage. By Alex. Adie, Esq. F. R. S. Edinburgh, 380

NOTICES TO CORRESPONDENTS.

Our Correspondent in Mexico, who has been so kind as to transmit to us two
papers in this Number, is requested to favour us with the continuance of his corre-
spondence through the same Channel.

We shall be happy to receive Mr Treoaskis^s paper on the bursting of Steam
Boilers.

We have been disappointed in not receiving Dr Hartmann's promised Com-
munication.

When Dr Hibbert returns from the Continent, he will no doubt enable us to
answer M's. inquiries respecting Auvergne.

Mr Sankey's valuable paper entitled, " Theory of the action of Caloric in pro-
ducing the expansion of fluids and solids, with a formula for the modulus of gravity,'*
came too late for insertion in this Number, but will appear in No. I. of our New
Series.

We have not seen the new Instrument called the Contrermrjil^ invented by Romer
of Paris ; but we may inform our Correspondent, that one of the agents for its sale is
Mr Frodsham of Grace-Church Street, well known as one of our ablest chronome-
ter makers.

' Mr Smith's highly interesting Communication will appear in No. I. of our New
Series.

In the arrangements for next Number, we shall follow X's advice as much as

possible.

THE

EDINBURGH
JOURNAL OF SCIENCE.

Art. I. — Biographical Account of Alexander Wilson, M.D*
late Professor of Practical Astronomy in Glasgow. By the
late Patrick Wilson, A. M. Professor of Practical Astro-
nomy in the University of Glasgow, *

Alexander Wilson, M. D. late Professor of Practical As-
tronomy in Glasgow College, was a younger son of Patrick
Wilson, town-clerk of St Andrews, and was born there in
1714. He was very young when his father died, and was af-
terwards brought up by the care of his mother, Clara Fairfoul,
a person much respected for her prudence, virtue, and piety.

Having received the usual education at the different schools,
he entered to the College of St Andrews, where he made great
proficiency in literature and the sciences, and, after completing
a regular course of studies, was admitted to the degree of Mas-
ter of Arts in his nineteenth year.

Before the expiration of his academical course, his inclina-
tion led him to prefer the study of natural philosophy, and
particularly those branches of it which relate to optics and
astronomy. From his earliest years he discovered a strong
propensity to several ingenious arts, among which may be men-

* This Memoir of Dr Wilson, after being read at the Royal Society of
Edinburgh on the 2d February 1789, was withdrawn by its author, for
the purpose of making some alterations upon it ; and was never returned
for publication. It was found, however, among the papers of Mr Patrick
Wilson, and is now printed with the consent of his family. Its connection
with the history of science, and of the progress of the useful arts in Scot-
land, gives it a very high degree of interest, and induces us to reprint it
from the Edin. Trans, vol. x.— Ed.

VOL. X. NO. I. JAN. 1829. A

2 Biographical Account of Dr Wilson^

tioned drawing, modelling of figures, and engraving upon cop-
perplate. Even when a boy, he often devoted his leisure to
such employments, and though in all of them he was almost
entirely self-directed and self-taught, yet, from time to time,
he produced specimens of ingenuity which drew upon him a
general attention, and which, by real judges, were considered
as indications of uncommon natural talents.

Upon his leaving the college, he was put as an apprentice to
a surgeon and apothecary in his native city, with a view of fol-
lowing that profession. At this period he became more parti-
cularly known to Dr Thomas Simson, professor of medicine in
the university, who ever after treated him with much kindness
and friendship. About the same time he had also the good
fortune to find a patron in Dr George Martine, a physician in
the town. In those days the construction and graduation of
thermometers was little attended to or understood in Britain,
and Dr Martine, from a just conception of the importance of
this instrument in many philosophical pursuits, was then em-
ployed in composing those essays on the subject of heat which
have rendered his name so justly celebrated. The author, be-
sides illustrating so well the theory of the thermometer, was
farther very desirous of bringing accurate thermometers into
general use ; and, with this view, he turned the attention of his
friend Mr Wilson to the art of working in glass. Though this
was to him entirely a new attempt, depending upon many trials,
and much mechanical address, yet he very soon acquired an
admirable dexterity in forming the different parts of the in-
strument by the lamp and blowpipe, and in constructing and
graduating the scales with accuracy and elegance ; an employ-
ment which, for a long time, Mr Wilson continued to be fond
of at convenient seasons, and in which it is well known he
greatly excelled.

Possessing naturally much activity of mind, and employing
most of his leisure in some ingenious attempt or other, it was
about this time that, in making certain optical experiments, he
discovered the principles of the solar microscope, so far as to
exhibit to several of his friends in a dark chamber the images
of small objects enormously magnified, by the sun''s rays en-
tering at a hole in the window-shutter, and after several refrac-

late Professor of Practical Astronomij in Glasgow. 3

tlons falling upon a white ground within. But Mr Wilson as
yet was too far separated from the great world, and had too
little experience for bringing forward to the notice of the pub-
lic any novelty of this kind ; and soon after, a similar combi-
nation of glasses, with additional improvements, occurred to
Mr Lieberkuhn, and was at length received as a very curious
enlargement of the optical apparatus.

It was also, whilst employing himself in such researches, that
Mr Wilson proposed to many of his philosophical friends the
idea of burning at a great distance by means of plain mirrors,
so situated as to throw the rays of the sun upon the same area,
without the smallest knowledge of such a thing ever having
been imagined by any person before him. But, wanting the
means of providing himself with any costly apparatus, the mat-
ter was pursued no farther ; and it is well known that M. de
Buffon, some years afterwards, when equally uninformed of
what Kircher had thought of, hit upon the same conception.
In 1747, by a magnificent construction far beyond the reach
of Mr Wilson's finances, the French philosopher showed what
might be done in this way, and with such effect as to render
the famous secret imputed to Archimedes, of setting on fire the
Roman galleys, much less apocryphal than it had ever been
considered before his time.

In 1737 Mr Wilson departed from St Andrews, and by the
advice of his friends went to London, in order to seek for em-
ployment as a young person who had been bred to the medical
profession. Soon after his arrival there, he engaged himself
with a French refugee, a surgeon and apothecary of good cha-
racter, who received him into his family, giving him the charge
of his shop, and of some of his patients, with a small annual
salary. About twelve months after he had been fixed in this
new situation, Mr David Gregory, professor of mathematics
at St Andrews, coming to London, introduced him to Dr
Charles Stewart, physician to Archibald Duke of Argyle, then
Lord Isla. Dr Stewart received him with great kindness, and
not long after made him known to Lord Isla, who very soon
was pleased to bestow upon him marks of his attention and fa-
vour. In his interviews with this nobleman, Mr Wilson had
his curiosity much gratified by some valuable astronomical and

4 Biographical Account of Dr Wilson,

physical apparatus which his Lordship had got constructed for
himself, and had placed in his library. On the other hand,
Mr Wilson was happy in being able to contribute in some de-
gree to the amusement of his patron, by constructing thermo-
meters of different kinds for him and his friends, with more
perfection and elegance than had been hitherto done at Lon-
don.

Near eighteen months elapsed in this way, during which
time he conciliated the good-will and esteem of his master, by
a faithful and regular discharge of whatever business was com-
mitted to his care ; and, in return, he found himself now and
then indulged in opportunities of keeping up his connections
with persons of a philosophical cast, when his attendance upon
the shop or patients could be conveniently dispensed with.
Mr Wilson has been often heard to speak of the satisfaction he
enjoyed even at this period, and of his perfect contentment with
every thing which had then fallen to his lot. But a serenity
of temper, and a felicity of disposition, were qualities which
eminently distinguished him throughout his whole life.

While he thus passed his time in what he considered as a
comfortable settlement at his first entering upon the world, a
circumstance of a very accidental nature occurred, which gave a
new direction to his genius, and which in the end led him to an
entire change of his profession. This was a transient visit which
he happened one day to make to a letter-foundery, along with
a friend who wanted to purchase some printing-types. In the
course of seeing the common operations of the workmen usu-
ally shown to strangers, he was much captivated with the cu-
rious contrivances made use of in that business. Some short
while afterwards, when reflecting upon what had been shown
in the letter-foundery, he was led to imagine that a certain
great improvement of the art might possibly be effected, and
of a kind, too, that, if successfully accomplished, promised to
reward the inventor with considerable emolument. His ideas
upon that subject he presently imparted to a friend a little
older than himself, who had also come from St Andrews, and
who was possessed of a considerable share of ingenuity, con-
stancy, and enterprise. The consequence of this was, a reso-
lution on the part of both these young adventurers to relin-

late Professor of Practical Astronomy in Glasgow. 5

quish, as soon as it could be done with propriety, all other
pursuits, and unite their exertions in prosecuting the business
of letter- founding upon an improved plan.

It was not long ere they were enabled to carry into effect
this resolution, and they first established a small type-foundery
at St Andrews, and one on a larger scale, two years after-
wards, at Camlachie, a village near Glasgow.

In this situation, Mr Wilson had contracted habits of inti-
macy and friendship with several persons of the most respec-
table character, particularly with the Professors belonging to
the University of Glasgow, and with Messrs Robert and An-
drew Foulis, university printers. The growing reputation of
the university press, conducted by these gentlemen, gave ad-
ditional scope to Mr Wilson to exert his abilities in construct-
ing their types, and being now left entirely to follow his own
judgment and taste, his talents as an artist became every year
more conspicuous. When the design was formed by the gen-
tleman of the university, together with Messrs Foulis, to print
splendid editions of the Greek classics, he, with great alacrity,
undertook to execute new types upon a model highly improved.
This he accomplished at an expence of time and labour which
could not be recompensed by any profits arising from the sale
of the types themselves. Such disinterested zeal for the honour
of the university press was, however, upon this occasion so well
understood, as to induce the university, in the preface to the
folio Homer, to mention Mr Wilson in terms as honourable to
him as they were just.

Though he thus continued to prosecute letter-founding as
his chief business, yet, from his great temperance, domestic
habits, and activity, he was enabled now and then to command
intervals of leisure, which he never failed to fill up by some
useful or ingenious employment. One of these, in which he
took great delight, was the constructing of reflecting telescopes ;
an art which he cultivated with unwearied attention, and in the
end with much success.

Among the more advanced students, who, in the years 1748
and 1749, attended the lectures on divinity in the university,
was Mr Thomas Melvill, so well known by his mathematical ta-
lents, and by those fine specimens of genius which are to be

6 Biographical Account of Dr Wilson y

found in his posthumous papers, published in the second vo-
lume of the Edinburgh Essays, Physical and Literary. With
this young person Mr Wilson then lived in the closest intimacy.
Of several philosophical schemes which occurred to them in
their social hours, Mr Wilson proposed one, which was to ex-
plore the temperature of the atmosphere in the higher regions,
by raising a number of paper kites, one above another, upon
the same line, with thermometers appended to those that were
to be most elevated. Though they expected, in general, that,
kites thus connected might be raised to an unusual height,
still they were somewhat uncertain how far the thing might
succeed upon trial. But the thought being quite new to
them, and the purpose to be gained of some importance, they
began to prepare for the experiment in the spring of 1749. *

Mr Wilson's house at Camlachie was the scene of all the
little bustle which now became necessary ; and both Mr Mel-
vill and he, alike dexterous in the use of their hands, found
much amusement in going through the preliminary work, till
at last they finished half-a-dozen large paper- kites, from four
to seven feet in height, upon the strongest, and at the same
time, upon the slightest construction the materials would ad-
mit of. They had also been careful, in giving orders early,
for a very considerable quantity of line, to be spun of such
different sizes and strength as they judged would best answer
their purpose ; so that one fine day, about the middle of July,
when favoured by a gentle steady breeze, they brought out
their whole apparatus into an adjoining field, amidst a nume-
rous company, consisting of their friends and others, whom
the rumour of this new and ingenious project had drawn from
the town.

They began with raising the smallest kite, which, being ex-
actly balanced, soon mounted steadily to its utmost limit, car-
rying up a line very slender, but of a strength sufficient to
command it. In the meantime, the second kite was made
ready. Two assistants supported it between them in a slop-
ing direction, with its breast to the wind, and with its tail laid

• As no public notice has hitherto been taken of this matter, though Mr
Wilson had always some thoughts of doing so, it is hoped the following de-
tail will not prove unacceptable or tedious to the reader.

late Professor of Practical Jslronomy in Glasgow. 7

out evenly upon the ground behind, whilst a third person,
holding part of its line tight in his hand, stood at a good dis-
tance directly in front. Things being so ordered, the extre-
mity of the line belonging to the kite already in the air was
hooked to a loop at the back of the second, which being now
let go, mounted very superbly, and in a little time also took
up as much line as could be supported with advantage, there-
by allowing its companion to soar to an elevation proportion-
ally higher.

Upon launching these kites according to the method which
had been projected, and affording them abundance of proper
line, the uppermost one ascended to an amazing height, dis-
appearing at times among the white summer clouds, whilst
all the rest, in a series, formed with it in the air below, such
a lofty scale, and that too affected by such regular and con-
spiring motions, as at once changed a boyish pastime into a
spectacle which greatly interested every beholder. The pres-
sure of the breeze upon so many surfaces communicating with
one another, was found too powerful for a single person to
withstand, when contending with the undermost strong line,
and it became therefore necessary to keep the mastery over the
kites by other means.

This species of aerial machinery answering so well, Mr Wil-
son and Mr Melvill employed it several times during that and
the following summer, in pursuing those atmospherical experi-
ments for which the kites had been originally intended. To
obtain the information they wanted, they contrived that ther-
mometers properly secured, and having bushy tossels of paper
tied to them, should be let fall at stated periods from some of
the higher kites ; which was accomplished by the gradual
singeing of a match-line.

When engaged in these experiments, though now and then
they communicated immediately with the clouds, yet as this
happened always in fine dry weather, no symptoms whatever of
an electrical nature came under their observation. The sub-
lime analysis of the thunder-bolt, and of the electricity of the
atmosphere, lay yet entirely undiscovered, and was reserved two
years longer for the sagacity of the celebrated Dr Franklin.
In a letter from Mr Melvill to Mr Wilson, dated at Geneva,

8 Biographical Account of Dr Wilson^

21st April 1753, we find among several other particulars, his
curiosity highly excited by the fame of the Philadelphian ex-
periment ; and a great ardour expressed for prosecuting such
researches by the advantage of their combined kites. But, in
the December following, this beloved companion of Mr Wil-
son was removed by death, — to the vast loss of science, and to
the unspeakable regret of all who knew him.

In the year 1752, Mr Wilson, who had married Jean
Sharp, daughter of William Sharp, a reputable merchant at
St Andrews, brought his family to Glasgow. About five
years afterwards, he invented the hydrostatical glass-bubbles,
for determining the strength of spirituous liquors of all kinds,
which long experience, especially among the distillers and mer-
chants in the West Indies, has now shown to be more accurate
and more commodious than the instruments formerly used.
From the minutes of a Philosophical and Literary Society,
composed of the professors and some of their friends, whose
meetings were held weekly within the college, it appears that
these hydrostatical bubbles made the subject of a discourse de-
livered by Mr Wilson in the winter of 1757. At this time he
also showed how a single glass-bubble may serve for estimating
very small differences of specific gravity of fluids of the same
kind, such as water taken from different springs, or the like.
This he did by varying the temperature of such fluids, till the
same bubble, when immersed, became stationary at every trial,
and then expressing the differences of their specific gravity, by
degrees of the thermometer, the value of which can be com-
puted and stated in the usual manner.

In the year 1758 he read another discourse to the same so-
ciety upon the motion of pendulums. On this occasion he ex-
hibited a spring-clock of a small compass, which beat seconds
by means of a new pendulum he had contrived, upon the prin-
ciple of the balance, whose centres of oscillation and motion
were very near to one another. At one of the trials it per-
formed so well as not to vary more than a second in about forty
hours, when compared with a very exact astronomical clock
near to which it was placed. It was some view of rendering
much more simple and cheap the machinery of ordinary move-

late Professor of' Practical Astronomy in Glasgow. 9

ments, by the slow vibrations of such a pendulum, which in-
duced Mr Wilson to prosecute these experiments.

Not long after this, he also put in execution a remarkable
improvement of the thermometer, which consists in having the
capillary bore drawn very much of an elliptical form, instead
of being round. By this means the thread of quicksilver upon
the scale presents itself broad, and much more visible than it
does in a cylindrical bore of the same capacity. The difficulty
of constructing thermometers of this kind had nearly hinder-
ed him from completing his invention, as the thread of quick-
silver was found extremely liable to disunite when descending
suddenly in so strait a channel. But, by his long experience,
joined to farther investigation and more trials, he at last dis-
covered a method of blowing and filling thermometers with
flattened bores, which freed them entirely from this defect.

About the same time, also, he conceived the design of con-
verting a thermometer graduated for the heat of boihng-water,
into a marine barometer, in consequence of the well-knov/n dif-
ference of temperature which water, when boiling, acquires un-
der the variable pressure of the atmosphere. This he effected,
by making a boiling-water thermometer, about a foot in length,
with a pretty large ball, and having a thread of quicksilver
as broad and visible as was consistent with a very perceptible
run upon small alterations of temperature. The stem of this
thermometer he fortified, by inclosing it in a cylindrical case
of white iron, having soldered to it, at its lower end, a socket
of brass for receiving half of the ball, which afterwards became
entirely defended, by screwing to the socket a hemispherical
cap. At the other end of the case which environed the stem,
there was soldered a tube of brass, wide enough to admit a
scale of proper dimensions, before which there was an opening
in the tube, defended by glass.

The utmost range of the scale he determined by the points,
where the thermometer was found to be stationary when the
ball, and a certain part of the stem were immersed in water,
boiling under the greatest variations of pressure which the
climate afforded. The interval so found, he subdivided by
other observations into degrees, which corresponded to inches of
the barometer, and which were so denominated upon the scale.

10 Bio^^raphical Account of Dr Wilson,

In the year 1756, the college of Glasgow, upon the death
of Dr Alexander Macfarlane of Jamaica, a great lover of, and
proficient in the sciences, received a legacy of a valuable col-
lection of astronomical instruments, which that gentleman had
got constructed at London by the best artists, and had car-
ried out with him to Jamaica, with a view of cultivating astro-
nomy in that island. The college, upon this, soon built an
observatory for their reception, which, by medals placed under
the foundation, was called by the name of their generous be-
nefactor ; and Mr Wilson was immediately thought of by the
members of the faculty, as a proper person for taking charge
of it, and making the astronomical observations. At this
juncture his Grace Archibald Duke of Argyle, who had all
along continued his patronage to Mr Wilson, more especially
since he had brought the art of letter-founding into Scotland,
used his influence with government, and procured his Majes-
ty's presentation, nominating and appointing him professor of
practical astronomy and observer in the College, with an an-
nual salary of fifty pounds, payable out of the Exchequer ;
and, accordingly, in 1760, he was admitted to this new office
by the unanimous and most cordial welcome of all the mem-
bers of the faculty.

His two eldest sons, who had by this time entered upon a
course of liberal education, not long after took upon them the
further enlargement and improvement of the letter foundery ;
and, before dismissing this topic, it deserves to be mentioned,
that Mr Wilson lived to such an advanced age, as to enjoy in
the most feeling manner the reward of his early diligence and
excellent example, in seeing the business rising in their hands
to the highest reputation, riot only in these kingdoms, but in
foreign countries.

In 1763, when upon a visit at St Andrews, an honorary
degree in medicine was conferred upon him by his Alma Ma-
ter.

Among the objects which now occupied him in the Obser-
vatory, his former labours towards improving the reflecting
telescope were resumed, and pursued for a considerable length
of time, with a view of obtaining some certain method of giv-
ing the parabolic figure to the great speculum. These trials

late Professor of Practical Astronomy in Glasgoiv. 11

were made upon a variety of metals, comparatively of a small
diameter, and focal distance ; but he regarded them only as
preliminary ones, and had always in contemplation to engage
with apertures of much greater dimensions. He was often
heard to regret, that no crowned head, or wealthy association,
ever thought of patronizing an attempt to construct some vast
telescope, to be employed in making discoveries in the moon
or planets, or in exploring the heavens ; and, it is more than
probable, that if his own means had been less circumscribed,
he would of himself have attempted something of this kind.
The more recent labours, and brilliant success of the excellent
Dr Herschel, have fully shown that such suggestions were by
no means romantic ; and the writer of this account, who has
had the happiness of being well acquainted with both these
men, has often remarked a striking resemblance in their cha-
racter and turn of mind.

In 1769, Dr Wilson made that discovery concerning the so-
lar spots, of which he has treated in the Philosophical Trails^
actions of London for 1774. Not long after he entered upon
this new field, the nature of the solar spots was announced by
the Royal Society of Copenhagen as the subject of a prize es-
say. This induced him to transmit thither a paper written in
the Latin language, containing an account of his observations,
and of the conclusions drawn from them. In return, he ob-
tained the honourable distinction of a gold medal of near six-
teen guineas intrinsic value, having, on its reverse, the figure
of Truth pendent in the air, holding a wreath in one hand,
and in the other a perspective glass, and the motto, Veritati
luciferce.

As an astronomical observer, he was remarkable for a sharp
and clear eye, devoid of all blemish, and which, too, without be-
ing liable to fatigue, had long been inured to examine and to
judge of small objects in their nicest proportions; a circumstance
which must have proved of great advantage to him when em-
ploying his sight upon celestial appearances by means of the
telescope ; and it required only to know him, to have the ful-
lest assurance of his fidelity in rendering an account of his ob-
servations.

His discovery in regard to the solar spots, though it be gain-

12 Biographical Account ofDr Wilson,

ing ground more and more among those most conversant in
astronomy, yet, like many other new discoveries, has not escap-
ed its share of opposition. This gave him occasion to publish,
in the Philosophical Transactions of London for 1783, the
second paper upon that subject, after a silence of near ten years,
wherein, upon the authority of many more observations made
in that interval, he obviates objections, and maintains the rea-
lity of his discovery with an entire conviction. The amount
ef it is, *' That the spots are cavities or depressions m that im-
mensely resplendent substance which invests the body of the
sun to a certain depth ; that the dark nucleus of the spot is at
the bottom of this excavation, which commonly extends down-
wards to a space equal to the semidiameter of our globe ; that
the shady or dusky zone which surrounds the nucleus, is no-
thing but the sloping sides of the excavation reaching from the
sun's general surface downward to the nucleus or bottom.""
All this he has demonstrated by a strict induction drawn from
the following phases of the spots, as they traverse the sun's
disk.

When a large well-formed spot, consisting of a dark nucleus,
and its surrounding umbra or dusky zone, is seen upon the
middle of the sun's disk, the zone is generally equally broad all
around ; but when the same spot verges near to the limb, that
side of the dusky zone which lies next to the centre of the disk,
begins much sooner than the side diametrically opposite to turn
narrower, and at last disappears, while the other still remains
dilated and visible. And, in like manner, when a spot enters
the disk by the sun's rotation, we see first the nucleus, and the
upper and under sides of tlie shady zone or umbra, together
with that side of it nearest to the limb, whilst the side opposite
is still wholly invisible. But as the spot advances farther up-
on the disk, that side of its dusky zone which lately was invi-
sible now shows itself, and continues to enlarge more and more
till it becomes as broad as any other part surrounding the
nucleus.

These phases, which he found so very palpable when ob-
serving carefully the great solar spot in November 1769, and
so very frequent, though less obvious, in numberless other spots
of a smaller size, which for several years afterwards he ex-

late Professor of Practical Astronomy in Glasgow. 13

amined, prove in the clearest manner that the spots themselves
are depressions in the luminous matter of the sun, and lead to
many new and interesting ideas concerniTig the nature and con-
stitution of that stupendous body.

But though he was the first astronomer to whose lot it fell
to remark these phenomena of the solar spots which have been
just now described, and to draw such important conclusions from
them, it appears that the celebrated Mr Flamstead, so far back
as the year 1676, had very nearly anticipated this discovery.
For, one day when observing a spot of considerable size near
the sun's limb, he actually beheld this appearance of the dusky
zone which belongs to the nucleus, finding it almost wholly
deficient on that side which respected the centre of the disk ;
and this, too, when the distance of the spot from the limb cor-
responded very nearly with that which Dr Wilson found to be
so constant in his observations. Mr Flamstead was then, in-
deed, viewing his spot in peculiar circumstances, and the most
favourable of all to perfect vision of the sun, as, by the inter-
vention of a mist, he was enabled to use his telescope without
the help of tinged glass put before his eye. The following is
his account of this remarkable observation, in which, by the
word macula, Mr Flamstead evidently means the nucleus of
the spot, and by nubecula the dusky zone which surrounds it.

" 1676, Nov. 9. Deinde densi adeovapores excepere solem,
ut per ipsos licuit ilium nudis oculis intueri. Adhibito turn
longiore tubo absque vitro rubro, (quo oculum adversus ejus
splendorem munire soleo) maculum contemplatus sum : dis-
tincta valde videbatur, ejusque figurae quae in schemate adpin-
gitur : ' Nubecula ipsi circumducta elliptica omnino ; sed,
quod vald^ miratus sum, admodum dilatata a parte limbum
respiciente ; ab altera vero versus centrum, maculae fere cohae-
rere videbatur.** "

" Observavi dein maculae a limbo proximo distantium 1'
13'/."" — Hist. Ccelest. Flamsteedii, vol. prim. p. 363.

When Dr Wilson saw the great spot on the 23d November
1769, it had nearly the same situation upon the disk, and the
same aspect as the one here described. But, at that time,
like Mr Fkmstead, he had no conception of what was signified
by such an appearance. It was not till next day, after remark-

14 Biogi'aphical Accmmt of Dr Wilson,

ing certain striking alterations of the form both of the nucleus
and umbra, that the suggestion first arose in his mind of the
spot being an excavation or depression on the luminous matter
of the sun ; which idea, the subsequent observations of the same
spot most evidently confirmed.

Not long before his death, in turning over at more leisure
the pages of this admirable astronomer, Dr Wilson for the first
time met with the above passage, and was pleased at finding so
remarkable a coincidence as to the leading fact upon which his
discovery rests.

Among his papers there were found many letters he had re-
ceived from Dr Maskelyne, upon whose correspondence Dr
Wilson set a very high value. All his papers published in the
Philosophical Transactions of London were communicated by
that friend. Among these, we find a short one in the volume
for 1774, wherein he proposes to diminish the diameter of the
finest wires, used in the focus of the astronomical telescope, by
flattening them according to a method there described ; an idea
which, though very simple, seems extremely worthy of atten-
tion.

In the month of January 1777, when conversing, as he often
did in the evenings, with his son, who had now made some pro-
ficiency in the sciences, their attention was somehow turned to
the following query, proposed by Sir Isaac Newton, among
many others, at the end of his optics, namely, " What hinders
the fixed stars from failing upon one another P''^

In reflecting upon this matter, they readily came to be of
opinion, that if a similar question had been put in respect of
the component parts of the solar system, it would have admit-
ted of a very easy solution, on 2iccour)to^ periodical motiofi ap-
pearing to them as the great mean employed by nature for
counteracting the power of gravity, and for maintaining the
sun and the whole retinue of planets, primary as well as secon-
dary, and of comets, at commodious distances from one ano-
ther.

In like manner, Dr Wilson thought it not unreasonable to
suppose, that the same principle might have assigned to it a do-
minion incomparably wider in extent, and that the order and
stability, even of a universe, and of every individual system

late Professor of Practical Astronomy in Glasgow. 15

comprehended in it, might depend upon periodical motion
round some grand centre of general gravitation. This con-
ception, besides appearing to them warranted by every view
they could take of the nature of gravity, seemed moreover to
receive some support from the discoveries which, since the time
of the great Halley, have been made of what has been called
the " proper motions of the fixed stars," and particularly from
the opinion entertained by that excellent astronomer, Dr Mas-
kelyne, " that, probably, all the stars are continually chang-
ing their places by some slow and peculiar motions through-
out the mundane space."

Soon after this view had arisen, out of the familiar conver-
sation above-mentioned, it was pubhshed in a very short ano-
nymous tract, entitled, " Thoughts 07i general Gravitatmi^
and Views thence arising as to the state of the U'ni verse.''''
The chief inducement to so early a publication was the hope
of drawing immediate attention to so interesting a point,
which might possibly lead to the discovery of some way by
which the matter might be brought to the test of observation.

It is quite obvious, that the foregoing suggestions necessa-
rily imply a motion of the solar system, as one of that im-
mense host, which, for what we yet know, may be subjected
to the laws of periodical revolution. Accordingly, it early oc-
curred, that perhaps the most advantageous way of advancing
in this investigation, might be to try to find out, if possible,
symptoms of such a law as afifecting that system to which we
ourselves belong.

It sometimes struck him, when looking over the progress of
philosophical discovery, that many things of high moment ap-
pear to have lain long wrapped up in embryo, by our not
employing ourselves more frequently in what may be called a
*' direct search,'''' and in filling up with more attention and bold-
ness the list of desiderata. Between this last step, and the ac-
complishment of a profound discovery, he conceived that the
transition might sometimes be made with no great effort of in-
vention, by only sifting carefully such principles as are already
known and familiar to us, and availing ourselves of them in
their full extent.

It was by proceeding in this way, ^id when considering the

16 Biographical Account of Dr Wilson.

manner by which the motion of light would be affected by re-
flecting and refracting media, themselves moving with great ve-
locity, (a most interesting field in optics then wholly unculti-
vated,) that two principles came into view, either of which may
possibly serve us in detecting a general motion belonging to the
solar system, relatively to the surrounding fixed stars, or in
proving a negative with regard to it. Of these, a very sum-
mary account has been given in the historical part of the Edin-
burgh Philosophical Tra7isactions, vol. i. But, should they be
successful in discovering such a concealed motion, the same
pnnciples cannot fail of determining the velocity and direction
of it ; and in process of time, whether such a translation of the
whole system be in a straight line or a curve, and if in a curve,
whether it be of a such a kind as may indicate a periodical re-
volution. And it needs scarce be mentioned, that if such a
thing should actually be made out, besides enriching astronomy
with that knowledge which depends upon measureable paral-
laxes in the sphere of the starry firmament ; it would also be-
stow a very high authority upon Dr Wilson's suggestions, of
what possibly may be the plan of nature in upholding the
universe.

At the time of the last-mentioned publication, he was sixty-
three years old, but still continued to enjoy the blessings of an
uninterrupted state of good health. In the year 1784, at the
recommendation of the university, his Majesty was graciously
pleased to nominate and appoint Patrick Wilson, A. M. Dr
Wilson's second son, to be assistant and successor to his father
as professor of practical astronomy and observer; a circum-
stance which heightened the consolations he enjoyed during
the evening of life.

In March and April 1786, when he had nearly completed
his seventy-second year, it became apparent to his family and
friends, that his constitution and strength were fast declining.
After a gradual and easy decay, which lasted throughout the
whole of that summer and autumn, and which he bore with
the utmost composure and resignation, amidst the tender soli-
citudes of his surrounding family, he at last expired in their
arms, on the 16th day of October.

The private character of Dr Wilson was amiable to an un-

On the Mean Temperature of Bombay/. 17

common degree. From his early youth to venerable age, he
was actuated by a rational and stedfast piety, enlivened by
those gracious assurances which carry our hopes and prospects
beyond the grave, and sweeten the lot of human life. The
cast of his temper, though uniformly cheerful and serene, was
yet meek and humble, and his affections flowed in the warmest
current immediately from the heart. His looks, as well as his
conversation and demeanour, constantly indicated a soul full
of innocence and benignity, in harmony with itself, and aspir-
ing to be so with all around it.

Art. II. — On the Mean Temperature of Bombay, deduced
J'rom Observations made in 1 827, ^c. Communicated by
Alexander Adie, Esq. F. R. S. E. &c.

1 HE observations from which the following results are de-
duced were made before sunrise, and at 11 o'clock a. m., 1
o'clock p. M., 4 o'clock p. m. and 9 o'clock p. m.

January 1827.

Before sunrise,
11 o'clock A. M.

1 p. M.

4 p. M.

9 p. M.

re for January,
February 1827.

re for February,
1829. B

Temp. Fahr.

69°07

76 58

77 56

78 55
73 00

Mean temperatu

74°95

Highest,
Lowest,

Before sunrise,
1 1 o'clock A. M.

1 p. M.

4 p. M.

9 p. M.

82
64

72^91
80 48
8153
82 05
77 87

Mean temperatu]

78 97

Highest.
Lowest,

VOL. X. NO. I. JAN.

85
69J

18 071 the Mean Temperature of'Bomhay.

Mauch 1827.

Before sunrise,

75*'44

11 o'clock A. M.

81 22

1 p. M.

8191

4 p. M.

82 30

9 p. M.

for March,

79 04

Mean temperature

79 98

Highest,

Lowest,

April 1827.

70|

Before sunrise.

77°28

11 o'clock A. M.

85 25

1 p. M.

86 11

4 p. M.

86 33

9 P. M.

for April,

82 68

Mean temperature

83 53

Highest,

Lowest,

May 1827.

741

Before sunrise.

82^95

11 o'clock A. M.

87 43

1 p. M.

88 14

4 p. M.

87 98

9 P.M.

! for May,

85 02

Mean temperature

86 30

Highest,

91.00

Lowest,

June 1827-

80.00

Before sunrise,

81°58

11 o'clock A. M.

8415

1 p. M.

84 43

4 p. M.

84 38

9 p. M.

82 23

Mean temperature for June, - - 83 35

On the Mean Temperature of Bombay. 19

August 1827.

Highest,
Lowest,

Before sunrise,
11 o'clock A. M.

1 p. M.

4 p. M.

9 p. M

Mean temperature for August,

Highest, - -

Lowest,

September 1827.
Before sunrise,

11 o'clock A. M.

1 p. M. »

4 p. M. -

9 p. M. -

Mean temperature for September,
October 1827.

Highest
Lowest,

Before sunrise,
1 1 o'clock A. M.

1 p. M.

4 p. M.

9 p. M.

Highest, - - - - 89

Lowest, - - _ - 76J

July 1827.

Before sunrise, . _ _ 80°58

11 o'clock A. M. - - - 82 41

1 p. M. - - - 87 64

4 p. M. - - - * 82 62

9 p. M. - - . 81 05

Mean temperature for July, -

82 86

84J
79

79°06
81 00
81 16
8122
79 79

80 45

771

78°95
8151
82 06
82 03
79 75

80 86

83J

79^4

84 83

85 59

86 14
8196

Mean temperature for October, - 83 53

JBO On the Mean Temperature of Bombay,

tures

Highest,
Lowest,

88
76i '

Before sunrise,

November 1827.

76^49

11 o'clock A. M.

83 51

1 p. M.

84 26

4 P.M.

84 35

9 p. M.

re for November,

80 30

Mean temperatu

81 78

Highest,
Lowest, -

87
67

Before sunrise.

December 1827.

68^70

11 o'clock A. M.

77 95

1 p. M.

78 70

4 p. M.

79 80

9 p. M.

[re for January,

7103

Mean temperatu

75 23

Highest,
Lowest,

84.00
59.00

lence we have for the mean monthly tempera

act "

January,

February,

March,

74°95

78 97

79 98

April,

May,

June,

~ ~

—

83 53
86 30
83 35

July,

August,
September, -
October,

82 86
80 45
80 86

83 53

November, -

81 78

December, -

75 23

Mean annual temperature of Bombay for 1827, 80°98

On the Mean Temperature of Bombay. 21

The slightest examination of the preceding observations is
sufficient to convince us that the mean temperature of Bombay
for 1827 must be considerably less than 80°98, which is the
mean of five ordinates of the daily curve. Three of the or-
dinates, viz. that of 11 a. m., 1^ p. m., and 4^ p. m. are taken
during the warm part of the day. The ordinate of Q'^ p. m.
is very little above the mean ordinate ; so that in the preced-
ing series of observations there is really only one ordinate,
namely, that before sunrise, which is near the lowest part of the
curve, and decidedly below the mean temperature. Two or-
dinates, therefore, or observations at 12 p. m. and about S^
A. M. are wanting to enable us to deduce from the series the
accurate mean temperature of Bombay.

Taking the mean temperature before sunrise as the lowest
during the day, we have by the Leith observations the follow-
ing correction : — *

Deviation from
Mean Temp.

Before sunrise, - — 2°873

11 o'clock A. M. - +1

I p. M. - + 2

4 P. M. - + 2 97^

9 p. M. - — 0 438

Sum of deviations from the mean, - + 4^^226

Hence we have

Observed mean temperature, - 80°98

Correction, - - - —* 4.226

Corrected mean temperature, ^Q'^lQ^i

If we now compute the mean temperature of Bombay in
N. Lat. 18°58' and east Long. 19P^&, by Dr Brewster's Ge-
neral Formula for the Eastern Hemisphere of the Globe we
shall find : —

« See this Jovrnal, vol. v. No. ix. p. 30.

i8 M. De Witt's Table of Magnetic Variations^ ^-c.

Mean temperature by formula, - 72^^58

Corrected observed temperature, - 76 76

Difference, 4^18

This difference, which is very considerable, may arise partly
from the insular situation of Bombay, which is no doubt warm-
er than in the same latitude on the continent.

Art. IIT. — Table of the Variations of the Magnetic Needle
at Boston, Falmouth, and Penobscot, in North America,
during 128 years. * By S. De Witt, Surveyor-Ge-
neral.

The following interesting document, which was furnished me
by the late General Schuyler, shows the changes in the varia-
tion needle at Boston, Falmouth, and Penobscot, from 1672
to 1800, embracing a period of 128 years. The difference
of variation between the two epochs appears to be 5^.5S\ giv-
ing a little more than 2|'ths for the mean annual variation.

As long as I can remember, the surveyors in our country
on retracing old lines have allowed at the rate of 3' per year,
and acquiesced in the correctness of that rule till 1805.

Since 1785, I occasionally observed the variation of the
needle, and from these observations I found no reason for
departing from the old rule till 1807, when, to my surprise,
I found that a sudden change had taken place in the direction
of the needle. In order to ascertain its extent, I examined a
number of lines which had been surveyed in 1 805, and which
gave a difference of 45' from July 30th, 1805, to September
4th, 1807.

I found the following to be the variation at Albany.

Variation.

1817, October 3d, - - 5° 44' West.

1818, August 1st, - - 5 45
1825, April 24th, - - 6 0

• Abridged from the Transactions of the Albany Institute, vol. i. No. i.
p. 4, June 1828.

M. De Witt's Table of Magnetic Variations, S^c. 2S

The following table exhibits the variation of the compass from
actual observation from 1672 to 1800. It was drawn up by
John Winthrop, Esq. Mollis Professor of Mathematics
at Harvard College in Cambridge.

Mean Ann.

Boston.

Falmouth.

Penobscot

Dift:

1672

15'

12°

15'

1678

1689

1700

14J

1705

15J

1710

12J

1715

1720

1725

1730

1735

1742

45
41

8
8

1745

1750

1757

1761

1763

1770

14|

1775

13|

1780

1785

1790

1795

14J

1800

15f

128 years DifF. 5" 53' 5° 53'

Mean Annual Difference, 2' 45" 28'^

NOTE BY THE EDITOR.

The preceding document, if correct, will be regarded as one
of great value by the natural philosopher. When we con-
sider, however, that the observations have been made at three

J84 M. Repetti on Quartx Crystals and Siliceous Paste

different places, and by various observers in the same place,
we cannot but view with suspicion the extraordinary coinci-
dence in the number 5° 53', which represents at three places
the difference of variation for 1S8 years ! The similarity be-
tween the differences of each period for the three different
places is also exceedingly suspicious. For example, from
1735 to 1742, the difference of variation is exactly 23' at each
of the three places of observation ; and in the following period,
from 1742 to 1745, the difference of variation is 4' at each of
the three places. Such a strange coincidence in the observa-
tions is not hkely to have taken place, even if the same obser-
ver and the same instrument had been the means of obtaining
them.

It would be highly desirable, therefore, both for science
and for the credit of those gentlemen whose respectable names
are connected with this document, that its history should be
diligently inquired into.

Art. IV. — Account of the Quartz Crystals, and the Sili-
ceous Paste Jbund in the Marhle of Carrara, as described
by M. Repetti. *

The cavities containing different fluids which occur in seve-
ral species of crystals have only a few years ago attracted the
attention of natural philosophers. We have already publish-
ed on this subject several important memoirs by Sir Hum-
phry Davy and Dr Brewster. In the present paper, I pro-
pose to give an account of the curious results contained in a
work by M. Emmanuel Repetti, entitled Sopre Valpe apu-
ana ed i marmi di Carrara. I ought to inform those who
are not much disposed to admit, without strong evidence,
facts of which they do not understand the cause, that in Italy
the knowledge and sincerity of M. Repetti are well known.
The rock crystals found in the marble quarries of Carrara

• This Analysis is translated from the Annates de Chimie, S^c. Jan.
1828, p. 86. The extracts only are from M. Repetti. See the following
article.

found in the Marble of Carrara. 25

are generally remarkably clear. Spallanzani was satisfied from
those in the museum of Pavia, where there is a great number
of specimens, that they surpass in limpidity the purest crys-
tals from Germany, Hungary, and Switzerland.

The largest and most perfect of these crystals are contain-
ed in irregular cavities of the calcareous mass in the crystal
ovens, as the workmen call them, (forni a cristalli,) per-
fectly closed on all sides. Here the crystals are insulated,
sometimes in groups, but always adhering to the marble.
Most frequently they are found implanted perpendicularly to
the sides of the cavities. Sometimes, however, their pyra-
midal extremities are free, and they touch the rock only by
the faces or angles of the prism.

The small crystals which are encased in the substance of
the marble have no transparency. Their colour is milk-white,
and their exterior form is not regular. One might suppose,
says M. Repetti, that want of room has also prevented them
from assuming the geometrical forms of crystals contained in
cavities.

Rock crystal is never found in the statuary Carrara marble.
It occurs in the common white pearly marble of the grottos of
Coloinbara delta Paiastra and the Fossa deW JngelOy situated
near the foot of Monte Sacro.

The workmen employed in the Carrara quarries informed
M. Repetti, during his first visits, that the cavities in the
marble which contained quartz crystals generally contained a
greater or less quantity of pure water, slightly acidulated ;
that they have often recourse to this fluid to quench their
thirst ; and that the crystals of calcareous spar encased in the
substance of the marble, and which they call luciche, are al-
most a certain proof that a liquid cavity containing quartz
crystals is not far distant. Hence the workmen have called
these crystals spies (la spia.) M. Repetti has satisfied him-
self of the accuracy of these observations.

I proceed now to the extraordinary fact which forms the
principal object of this paper,

" In the spring of 1819, M. Pontaleone del Nero, proprie-
tor of a quarry in the Fossa del Angelo, having caused to be

S6 M. Repetti on Quartx Crystals and Siliceous Paste

sawn in his own presence the shaft of a great column for the
new church of St Fran9ois at Naples, perceived a lucica. This
led him to probe the marble with an iron, when in an instant,
and to the great surprise of all those who assisted at the ope-
ration, there was seen a cavity larger than usual, every where
lined with crystals, and containing about a pound and a half
of liquid. With still greater astonishment they saw at the
bottom of the cavity a transparent pjvtuberance as large as
the Jist, and which seemed to have all the characters of rock
crystal. Transported with the idea that he was about to
possess himself of the purest specimen of hyaline quartz in the
world, he instantly attempted to detach it from its matrix ; but
alas ! he had scarcely withdrawn his hand from the cavity be-
fore he saw an elastic and pasty substance, which at first might
have taken any shape, and received any sort of impression.
It soon, however, became solid and opaque, when it had the
aspect of calcedony, or of a fine porcelain biscuit. Disap-
pointed by this unfortunate metamorphosis, and putting no
value on a substance, the whole importance of which seemed
to him to be gone, M. del Nero threw it in vexation among
the debris of marble collected in the ravine."

Such is the account given in the very words of M. Repetti.
This naturalist does not dissemble that it may be considered
incredible ; but, according to him, every person present gives
the same account, and among these were several well worthy
of credit. Besides, he adds, the fact quoted by M. del Nero
is not unique, though examples of pasty crystals as large as
his have not occurred.

When Spallanzani visited Carrara in 1783, the workmen
told him that they sometimes found in the marble crystals
which became hard after they were taken out. " But I have
discovered," says Spallanzani, " that this opinion is not true.
The quartz contained in the marble is as hard before its ex-
traction as after it is exposed to the air, which is also perfectly
conformable to the laws of crystallization." To this positive
denial of the fact related by M. Nero, M. Repetti replies, that
M. Spallanzani misunderstood the workmen, and that he mis-
took for a general law what was stated to him only as an ex-
ception.

found hi the Marble of Carrara. 27

Such was the state of the question when M. Repetti pub-
lished his work in 1820. Since that time he has inserted in
the Anthologia an observation which he made along with M.
Pompeo Pironi, a naturalist of Milan, and which appeared to
him to remove every doubt.

" In passing," says he, " to the vvest of the Foce della Bru-
ciana, I observed accidentally a micaceous marly rock of a
chestnut colour, and of the kind which the French call molasses
where, if I may use the expression, nature was caught in the
fact.

" In a vertical section of the ground contiguous to the new
road, I observed some veins or contorted fissures which tra-
versed the mass of marl, and were covered with quartz and
calcareous spar, and from which there issued, as if the water
of infiltration pushed it from within outwards, a substance
transparent and viscid between the fingers., like the gum
which eocudes from trees.

" I immediately recollected the fine experiments of Berze-
lius, by which he showed that one of the characteristic pro-
perties of .9z/e<2? was, that it precipitated itself from solution in a
gelatinous form, and the phenomenon quoted in my work on
a pasty mass found in 1819, in an anhydrous geode of Carrara
marble. I was instantly satisfied that the fact which I had
discovered afforded an irrefragable proof of the recent forma-
tion of quartz crystals in the cavities and fissures of calcareous
rocks.

" My first care was to extract from the fissure a portion of
the semifluid substance, and to wrap it up in a sheet of paper,
with the view of submitting it to chemical analysis. I also
thought of impressing upon it some figure which might prove,
in the event of its becoming solid, that it had been originally
fluid, but its extreme liquidity prevented me from doing
this.

" In the evening of the very day on which I discovered it,
I found that the paste contained in my sheet of paper had be-
come solid, opaque, friable, rough to the touch, and of a zMte
tint:'

In the remainder of his paper, M. Repetti relates a series

28 Formation of Quartz Crijstals.^cfrom Siliceous Solutions.

of experiments made at Florence in concert with Professor
Taddei, and from which it follows that the pasty substance
was composed of

Silex, - - 5 parts.

Lime, - - 1

for the author supposes from the details of his analysis that
it was not a simple mixture.

The reader has, however, before him the elements of the
question, and may judge for himself whether or not the obser-
vation of M. Repetti is sufficiently precise to obtain sl place in
science. Some may perhaps regret that this naturalist did
not insist more on the circumstances relating to the transpa-
rency of the substance which he analyzed, and that of the large
pasty mass extracted from the marble by M. Nero. With re-
gard to the objection of Spallanzani it can have no weight,
since the phenomena of polarisation have proved that the jellies
of oranges and gooseberries are really crystallized, and that
they even possess double refraction.

Art. V. — Facts and Observations relative to the recent Jbr~
motion of Qioartz Crystals^ Sfc. and of indurated Calcedony
from Siliceous Solutions and Pastes.

As we have not been able to procure the original work of M.
Repetti, we are glad to have it in our power to lay before our
readers the copious extracts from it given in the preceding
article, although we had six years ago published in the Ed.
Phil. Jcmrnal the simple facts which he had observed.

The English scientific reader will doubtless partake in the
surprise with which we have read the observations of the learn-
ed French editor on the paper of M. Repetti. The facts are
brought forward as something quite new and unique, as some-
thing which geologists have overlooked, and as bordering on
the marvellous ; and the reader is told that he must judge for
himself whether or not the observation of M. Repetti is suffi-
ciently precise to receive a place in science.
In England we have been long familiar with analogous and with

Formation of Qudtrtz Crystals ^^c, from Siliceous Sohitions. 29

similar facts, and even with facts far more puzzling than those of
M. Repetti. Our mineralogists and geologists and natural phi-
losophers never doubted the testimony upon which these were
published ; and, with the exception of some red-hot Plutonists,
whose prejudices were opposed to the belief that many minerals
have been, and are now, forming from aqueous deposition, we
never met with any unprejudiced philosopher who did not ad-
mit the facts as implicitly as any other in physical science. For
our part, we cannot see where the wonder lies. Among the
extraordinary facts on which every science is founded, and many
of which are every hour obvious to our senses, is it at all a mat-
ter of wonder, or is it even slightly marvellous, that a soft
transparent siliceous mass should be found in the cavity of a
calcareous rock, and should harden into something like calce-
dony or porcelain, or that a calcareo-siliceous gelatinous mass
should become solid, opaque, and friable?

The following are a few of the facts which ai'e impressed on
our memory, and which it may be interesting to bring to-
gether.

1. Spongy Amorphous mass of Carbonate of Lime formed
by the evaporation of a Fluid in a Cavity. — Count Bournon,
Mineralogy, vol. ii. p. 35, informs us, that in the vicinity of
Lyons there is a calcareous rock containing often very large
geodes, having for their envelope silex mixed with lime, fre-
quently alternating in concentric layers. Within these geodes
beautiful crystals of carbonate of lime occur, mixed with those
of quartz, which they rivalled both in transparency and per-
fection of form. Upon breaking numbers of these geodes,
Count Bournon found some of them full of water, and on one
occasion he obtained half of a geode with the water which it
contained unspilt. Observing that the fluid moved with a
massy heaviness like mercury, he concluded that it must be a
very concentrated solution ; and as this happened at mid-day
in a warm day in July, the fluid was all evaporated in little
more than a quarter of an hour, and there reinained in the
geode a spongy amorphous crystalline mass of carbonate of
lime.

About the same period Count Bournon observed the same

30 Formation of Quartz Crystals, S^c.from Siliceous Solutions.

thing at Vougy, but the geodes were composed of black oxide
of manganese lined with crystals of carbonate of lime.

ft. Quartz Crystals formed iu the ohserver'^s presence from
a siliceous solution in a cavity. — As we have already given a
full account of this fact in this Journal, No. iii. p. 14], we
shall merely state that Mr B. F. Northrop, of Yale College,
found in the centre of a hornstone pebble a cavity three-
fourths of an inch long, by half an inch wide, a milky fluid,
like magnesia and water. While the rapid evaporation pro-
duced by a hot day was going on, " minute prismatic crystals
shot from the fluid even under the eye of the observer.''''
These crystals were found to be quartz. In other cavities lined
with mammillary chalcedony, he found a white spongy depo-
s^lte resembling an earthy precipitate.

3. J Gelatinous, Siliceous, and Impressible Mass found i7i
the cavities of a Pebble. — In the centre of a hornstone and chal-
cedony pebble, five inches by three, Mr Northrop found a cavity
1 J by 1 inch, nearly filled with a spongy siliceous deposite, which
was still moist to such a degree, " as to form a pulpy or gelatinous
mass, very soft and impressible, which also soon dried by the
intense heat of the weather.'''' A few crystals also shot here
and there as in the preceding cavity. " In a Jew cavities the
silicecms matter had concreted into well characterized mammil-
lary chalcedony.^'' — See this Journal, No. iii. p. 141.

4. Hollow Balls containing from a pint to two quarts of a
milky fluid. — Mr E. Whiting of Newhaven saw in 1806, in
Georgia, hollow balls like bombshells, which had been pre-
viously found, and which were filled with a milky fluid so
nearly resembling white paint or white wash, that it was used
to whiten the fire-places and walls of the houses. These shells
were from 5-8ths to 3-4ths of an inch thick, and their crust
looked like an iron ore. Their capacity was from a pint to
two quarts. They were found in excavating a mill-dam in
Brier Creek, a stream which passes through Millhaven, and
flows into the Savannah river, and at the distance of two or
three miles from the road leading from Savannah to Augusta.
See Prof. Silliman's Journal, vol. viii. p. 285, and this Jour-
nal, No. iii. p. 142.

5. Siliceous Tabasheer formed from a milky and viscid

Formation of Quartz Crystals .^ ^c.from Siliceous Solutions. 31

juice. — The regular substance called tabasheer, with which
our readers are familiar, is a purely siliceous substance, trans-
mitting a yellow, and reflecting a fine blue light like certain
opals, is formed in the joints of the bamboo from a milky juice
which is sometimes in the state of honey. Those pieces of
tabasheer have the veined structures and other properties of
chalcedony.

6. Doubly Refracting Crystals of Quartz formed in the Si-
liceous Grasses. — It has been long known that silex existed
in these grasses ; but Dr Brewster has discovered that this si-
lex occurs in crystals, having the property of double refraction
and polarisation, and having all their axes geometrically ar-
ranged. These crystals, which exist in thousands in every
plant, form an essential part of it. We shall soon lay the
author's paper on this subject before our readers.

7. Crystals of Sulphate of Barytes formed from the fluid
in a cavity.— In this Journal^ No. ix. p. 135, we have al-
ready laid before our readers an account of the curious fact
discovered by Mr Nicol, of the fluid in a cavity of sulphate
of barytes exuding from the cavity, and forming a crystal of
the same mineral. We have seen this crystal, and the most
irrefragable proof of its having been thus formed.

8. Silex formed from the juices in Teak Wood. — In various
specimens of teak wood, Mr Sivright observed actual cry-
stallized quartz, and we have also seen them in his specimens
in the distinctest manner. (kI

9. Beryls found in a soft state in Siberia. We have some-
where read that M. Patrin, a French mineralogist, found be-
ryls in Siberia, which, when newly taken out of the earth,
broke across like a piece of apple.

10. Opals found in the state of soft tenacious paste in Hun-
gary.— M. Beudant, a celebrated mineralogist, now in Paris,
gives the following account of this fact in his travels in Hun-
gary.

" There exists in the most solid and freshest parts of the
rock small nests of a very soft matter, which readily cuts, and
produces a particular unctuosity under the edge of the knife.
This matter is whitish, yellowish, bluish, and sometimes it
presents indications of iridescent reflections. It is very soft

32 Formation of Quartz Crystals, S^c.from Siliceous Solutions.

to the touch, and when it has imbibed water, becomes suffi-
ciently tenacious to be kneaded between the fingers. I can-
not believe that this matter is owing to a decomposition of
opal, similar to that which we have just mentioned, since,
from the manner in which it occurs inclosed in the rocks, it
could not have been exposed to the influence of the air. I
am rather of opinion that it is a particular state of opal. The
workmen also distinguish those earthy parts, which they re-
gard as opal that is not yet ripe, from those which are pro-
duced by the exposure of opal to the air, which they name
burnt or calcined opal. These matters harden a little on ex-
posure to the air, and crack in collections, precisely the same
way as alumina or silica in a state of jelly, which are desic-
cated in our laboratories. It has been without doubt obser-
vations of this kind, which have led certain authors to say,
that opals are found, when in the bowels of the earth, so soft
as to receive the impression of the fingers, and that they har-
den only by exposure to the air. This idea is not perhaps so
ridiculous as might at first be imagined ; for we know that si-
lica in solution assumes in drying, a certain degree of hard-
ness, and a lustre approaching to that of opal. It is true that
the greater number of opals are solid when taken from the
rock; but after finding them occasionally still soft, and capable
of drying in the air, might it not be supposed, that the rest
have undergone this desiccation in a slower manner in the
bowels of the earth ? By admitting this hypothesis, we can
discover the reason of the difference which exists between the
hyaline quartz and opal ; the quartz will be the product of a
crystallization of the siliceous matter, and the opal the result
of the desiccation of a gelatinous precipitate. I must remark,
however, that this is merely a hypothesis, which, while there
are some facts in favour of it, has also others against it ; such
for example is the existence of opal stalactites, with regard to
which it must be admitted that the matter has been in a kind
of solution."

Mr Harvey on a remarkable Formation of' Clouds. 33

Art. VI. — On a remarJcable Formation of Clouds. By
George Harvey, Esq. F. R. S. Lond. and Edin. F. L. S.
Honorary Member of the Society for promoting the Useful
Arts of Scotland, Member of the Royal Geological Society
of Cornwall, &c. &c. Communicated by the Author.

If the capricious alterations of our climate sometimes produce
inconvenience, and augment the calamities of querulous and
unquiet minds, there is enough to reward the attention of the
most active and watchful meteorologist in the beautiful variety
which the ever-changing aspect of the sky presents.

An example occurred at this place, the latter end of the
past month, of a remarkable uniformity in the clouds, which it
may not be improper to record in a more permanent manner
than in the perishable pages of a private journal. About two
p. M. on a day which had all the warmth and serenity of June,
and when even a freshness seemed to come over " the sear and
yellow leaf,'^ a beautiful assemblage of separate and distinct
bands of delicately formed cirro-cumuli were observed to
spring up from nearly the southern extremity of the magne-
tic meridian, and, diverging in all directions, became blended
at last with the same beautiful uniformity near the northern
pole of the same great line, the whole group bearing a strong re-
semblance to the meridians of a common globe when rectified
for the equator. The band which passed through the zenith,
and whose axis was nearly coincident with the magnetic" meri-
dian, was particularly distinguished by its fine regularity of
form, and the symmetry pervading the small masses of cloud
that composed it. The bands on either side diminished suc-
cessively in breadth, the narrowest and lowest on each side
being at an elevation of from fourteen to fifteen degrees. The
lower bands seemed in some degree to exchange the character
of the cirro-cumulus for that of the cirro-stratus.

This very novel appearance continued the whole of the af-
ternoon, and was clearly visible at half-past six o'clock, cover-
ing the azure, now studded with innumerable stars, in a man-
ner that very much increased the interest of the scene. At
seven gentle vapours began to arise ; and before eight the

VOL. X. NO. r. JAN. 1829. c

34 Mr Kenwood's account of the

whole hemisphere was shrouded in gloom, presenting a strik-
ing contrast to the liveliness and beauty which had characterized
all the former part of the day.

A very gentle breeze prevailed from the E. S. E. The ba-
rometer at 3 o'clock stood at 301 ; and the temperature in the
shade was 55°.

Plymouth, Nov. 1, 1828.

Aet. VII. — Account of the Steam-Engines in Cornwall. By
W. J. Kenwood, Esq. F. G. S., &c. &c. Communicated
by the Author.

Shortly after the expiration of Messrs Boulton and Watt's
patent right, they relinquished the superintendence of the
steam-engines which they had erected on the Cornish mines ;
and they were consequently committed to the care of those
who had been convicted of infringements on the patent, or to
that of the mine-agents. None of those persons having been
acquainted with the reasons which had influenced Mr Watt's
operations, in avery short time, theduty, which had been advan-
ced to an average of above twenty millions of pounds weight,
lifted one foot high by the consumption of a bushel of coal, sub-
sided to an average not exceeding fourteen millions ; and the
performance of many engines was not more than siw millions.
Some of the pirators who were intrusted with the erection
of new engines, having, during the continuance of the patent,
found it of importance to get their engines into operation as
speedily as possible, without regard to accuracy or proportion,
with the sanction of the miners, still continued to pursue the
same practice ; the consequence of which was, that the scien-
tific precision which had been introduced by Mr Watt was
regarded as an object of secondary consideration. Some of
those erections (for they were scarcely worthy of being termed
machines) could only have been viewed as caricatures of the
original. Others followed Mr Watt's steps, as closely as, with-
out the assistance of science, they were enabled to do, and
produced some tolerable imitations. But all fell more or less

Steam-Engines in Cornwall SB

short of what had been obtained, whilst his superintendence
continued.

The increasing depth of the mines requiring that the me-
chanical force should be augmented, a greater quantity of
steam became requisite. Mr Watt had already made the
boilers as large as he considered prudence to warrant, and ob-
tained an increased supply by using several boilers. But the
Cornish engine-builders imagined that the dimensions might be
enlarged, and that they might thus avoid the necessity of em-
ploying a greater number; the consequence of this mistake was,
that the boilers were made of the most unwieldy dimensions.
The theory of combustion was not in those days so generally and
accurately known as it is at present, and the fires in Mr Watt's
engines were of much larger dimensions than Mr Smeaton's ex-
periments, now confirmed by more extensive experience, have
demonstrated to be most consistent with economy of fuel.

In some of the engines which were erected by the mine-
agents, the fire bars were placed more than ten feet below the
bottom of the boiler, as much as possible, and often nearly
the whole, of the intervening space, being filled with ignited
fuel. Under such circumstances, it must be evident that ten
millions would have been the extent of their performance.
From this general censure, we must, however, except several
engines erected by Mr Hornblower, particularly two large
double acting engines at the united mines, which, in propor-
tion and performance, were equal, if not superior, to any of
those which Messrs Boulton and Watt had erected in Corn-
wall, Mr Trevithick, who was a large contractor for the erec-
tion of steam-engines, made several ; but, as he paid but little
attention to the proportion of the parts, their performance was
not very good. His high pressure engine was first adopted,
in consequence of a scarcity of water for injection, and, among
many other excursions of his fruitful fancy, was the cylindri-
cal tube boiler, now generally used in Cornwall. About the
year 181 2, Mr Woolf came into Cornwall. He had also invent-
ed a boiler which was said to possess many advantages. It
consisted of a body or reservoir beneath, and connected with
which were several tubes, and between them the flame and
heated air traversed in their passage to the chimney. Being

36 Mr Henwood's account of the

usually made of cast-iron, and continually exposed to the in-
tense action of the fire, the water was frequently driven out of
them, and their temperature became considerably elevated ;
by the readmission of water at a comparatively low tempera-
ture, they were rapidly cooled, and the consequent contraction
occasioned the frequent fracture not only of the joints, but
also of the tubes themselves. Frequent trials demonstrated
their inferiority to those of Trevithick, in favour of which
they were soon relinquished.
w Previously to Mr Woolf 's coming into Cornwall, he had
revived Mr Hornblower"'s idea of employing the expansive
force of steam in a second cylinder ; and by having his en-
gines made and fitted together in a much more accurate man-
ner than had hitherto been the practice in that neighbour-
hood, he succeeded in obtaining from engines of that construc-
tion a very much better performance than had yet been effec-
ted by Mr Watt^^s engines. Mr Woolf and his friend, the late
Dr Alexander Tilloch, by their frequent publications on the
subject, industriously propagated the opinion of this superio-
rity ; and to this and Mr Woolf's alleged experiments are due
the very absurd notions of the great economy from the use of
highly elastic steam, which for so many years obscured that
quarter of the scientific horizon. We believe the explosion
of this theory (if it be worthy of the appellation) was effected
by Mr Dalton''s discovery of the law which determines the
dilatation of the permanently elastic fluids by increase of heat.
We are informed, that, soon after the erection of some of Mr
Woolf 's engines in Cornwall, one which worked at Huel
Abraham mine, during a trial which was continued for twenty-
four hours, lifted seventy millions of pounds one foot high by
the combustion of one bushel of coal.

By dint of great attention to the joints, &c. of the engine
at Huel Abraham, its average duty was very far beyond that
of Watt's engines, then at work in the neighbourhood ; a
statement of their performance being periodically published.
The adventurers in mines and the engineers now began to
see the important advantages to be derived from attention to
proportion and accurate workmanship, and the founders in
Cornwall erected apparatus for the preparation of machinery

Steam-Engines in Cornwall. 37

The performance of the steam-engines gradually increased to
an average of between twenty and twenty-five millions, the lat-
ter being by no means a frequent occurrence.

Mr Sims now erected two or three engines on a plan which
was a combination of the high pressure with Watt's, and their
average was probably little short of thirty millions ; however,
this advantage was entirely attributable to the greater degree
of attention paid to their erection.

During or about the year 1820, the well-known and exten- h
sive consolidated mines in Cornwall were put into active ope-
ration, and Mr Woolf, who was appointed the engineer, ex-
pressed an intention to erect some engines of the two cylinder
construction. This was opposed by Mr William Francis, a very
intelligent mine-agent in the employ of Mr John Taylor, and
in consequence, some very large engines on Watfs principle
were made. Every attention was paid to proportion and work-
manship, and their performance fully justified Mr Francis's
views of the subject.

The unprecedented activity of mining enterprize which
immediately succeeded required the preparation of many new
and powerful steam-engines, and in their construction as much
attention was given to the proportion and preparation of the
parts as the scientific attainments of the superintendents af-
forded. Forty and even forty-eight millions was not now
considered a singular occurrence. Much of the credit of
this is unquestionably due to Mr Woolf. The superiori-
ty of Mr Watt's engines was now considered beyond doubt ;
and but one of Mr Woolf's has been since erected. Towards
the termination of the year 1826, Mr Grose was called on to
superintend the preparation of some steam-engines at Huel
Towan mine ; and the average duty of that which was first
worked was nearly fifty millions. A coating of saw dust of
about ten inches in thickness was now applied to the steam-
pipes, nossel, cylinder, &c. and about an equal depth of ashes
to the top of the boiler. The duty was by this means increas-
ed to about sixty-five millions. A loss of caloric still obtaining,
another coating of about the same depth, and of like materials,
was applied outside the former, the consequence of which
was a further increase to eighty-seven millions, which was the
average of a trial at which the writer of this notice was pre-

38 Mr Hen wood's account of the

sent, with several engineers and scientific men. Following Mr
Grose's idea, Mr Woolf has brought one of his engines to an
average duty of nearly seventy millions, and other engineers
still following are not far behind. Its effect will be traced
by inspecting the tabular view which accompanies this article.
Ignorance of this important object precludes, in many in-
stances, xhafnll benefit being now derived from its application ;
but its partial adoption must in every case be beneficial.

Mr Grose has realized a similar advantage in other engines,
and it would have afforded us'great pleasure to have given a
view of other important improvements which he contemplates ;
but as they are not yet in operation, it would now be prema-
ture ; however, we hope soon to be able to lay a detail of them
before the public, in an early number of the Edinburgh Jour-
nal of Science.

On some peculiarities in the construction and manner of work-
ing usual in CornzvalL

It is found in practice that the maximum effect from a
given quantity of fuel, obtains when the fire is from eighteen
to twenty-two inches below the highest part of the concavity
of the inner tube ; when the depth of ignited matter does not
exceed fourteen inches, and is not less than eight ; and when
the boilers are sufficiently capacious to supply the requisite
quantity of steam, the damper being so far closed as to allow
the whole of the smoke to pass slowly to the chimney, but still
so rapidly as to keep a bright fire without any other stirring
than the removal of the cinders requires. If the draught be
too slow, the brightness of the fire will diminish, and the smoke
and heated air will escape at the fire doors, which must be at-
tended by much loss of caloric, as well as by great inconveni-
ence to the attendant. If the draught be too brisk, the gaseous
matter will pass so rapidly through the fuel as to escape to
the chimney before its temperature has been reduced to that of
the boiler.

The same effect will obtain, if a fire deeper than fourteen
inches be made, and the damper opened so far as to keep up a
brisk flame ; and if the fire be less than eight inches deep, it
will permit the influx of a disadvantageously large quantity of

Steam- Engines in Cornwall. 39

air into the fire-place ; but if the fire do not burn briskly, there
is a probability that a portion of coal gas will pass off without
undergoing combustion, and consequently without affording
any assistance. It is perhaps almost unnecessary to observe,
that no more air should be admitted into the fire-place than
is requisite for the maintenance of the proper degree of activi-
ty in the combustion and draught, and this degree must be the
smallest of which the demands of the engine will admit. It is
an object of importance, that the pipe by which the steam is
conveyed from the boiler to the cylinder should be consider-
ably inclined towards the former ; thereby permitting the re-
turn to the boiler of any water which may have obtained from
condensation in the pipe. For were this water to enter the
cylinder, it might be easily apprehended that its effects would
be very detrimental ; it would probably occasion further con-
densation, and very much augment the adhesion of the pack-
ing of the piston to the cylinder. Hence the importance of
coating the steam-pipe with a considerable depth of non-con-
ducting matter. This point is much insisted on by Mr Grose,
who maintains that the adhesion, even when the packing is
well oiled, is much greater at low than at high temperatures.
It seems that a load of between nine and twelve pounds on
the inch of the area of the piston, is the most advantageous
to the performance of the steam-engine, and we think Mr
Watt entertained an opinion not very different from this, al-
though we are not prepared to assign any very satisfactory rea-
son for its being so. The whole of the pumping engines in
Cornwall raise the column of water during the returning stroke,
and, as but few of them work without an interval between each
stroke, the means of considerably assisting their operation is
thus afforded. A counterpoise to the weight of the pump
rods is alvvays required, and the quantity of this is so adjust-
ed as to occasion the return to be made very slow, and to ter-
minate but an instant before it is necessary to make the suc-
ceeding stroke. Hence it is evident, the more slowly the re-
turning stroke is made, the smaller the quantity of steam re-
quisite to make the working stroke. But it is obvious that
this assistance can never be given either to rotatory or to
double reciprocating steam-engines, that which would have
been gained on one hand being lost on the other ; consequently,

40 Mr Kenwood's account of the

the performance of single is better than that of double recipro-
cating or rotatory engines. But as the latter are never work-
ed ** expansively,"" this accounts for a small portion of the dif-
ference. An advantage of some consideration is obtained in
the pumping engines, by allowing the exhausting valve to be
opened before the steam is admitted on the piston, which con-
sequently meets a considerably smaller resistance at the com-
mencement of its motion than it would have, had both valves
been opened at the same instant.

It is not unusual to force the water intended to replace the
evaporation from the boilers into a separate vessel kept con-
stantly full of liquid, and around which the flue from the boiler
to the chimney is passed. It thus attains a temperature but
little below that of the water in the boilers, which are sup-
plied by opening a communication between them and this ves-
sel, into which a portion of liquid is now injected; and this
displaces an equal bulk of the warmer liquid which passes into
the boiler. There are at Huel Towan engine three boilers,
each about thirty-six feet long ; the outer tubes are six, and
the inner four feet in diameter ; the area of the fire grate is
in each about twenty-eight or thirty feet. The writer of this
notice has observed that engines with boilers of smaller capa-
city do not perform such duty. Some of those next in good-
ness have a greater and others a less reservoir of steam. It ap-
pears that the dimensions of Huel Towan are most efficient,
but that a smaller quantity is preferable to a larger. We be-
lieve that the importance of attending to the operation of the
air-pump has not since Mr Watt's time been sufficiently noticed.
We think the following remarks will help to place the subject
in a proper point of view. The quantity of water should be
as small as possible, not so much on account of its weight, as of
the greater period during which the piston of the air-pump will
be exposed to the atmospheric pressure. On the other hand,
the smaller the quantity of water injected, the higher will be
the temperature of the hot well, and consequently the less per-
fect the vacuum. It is obvious that the smaller the quantity
obtained, by adding the difference between the impeding influ-
ence of the vapour of the hot well on the piston, and its acce-
lerating action on the air-pump, to the whole resistance expe-

Steam-Engines in Cornwall. 41

rienced by the latter during its exposure to the atmosphere,
the better will be the operation of the machine. Mr Watt
thought 102^ to 110° to be the temperature of his hot well
when the engine performed the best duty.

The following table will exhibit an approximation to the
resistance that is opposed by the air-pump at Huel Towan at
various temperatures of the hot well.

Temp.

Resistance to

Accelerating effect

Total resistance to

air-pump from

piston from va-

of vapour on air-

air-pump.

atmosphere.

pour.

pump.

80°

33993,26

17995,8528

903,876

51085,2368

24114,67

21076,224

1058,5935

44132,3005

22650,047

21835,53

1094,21885

43391,35815

21475,65

22292,16

1119,665

42658,145

20360,62

22901,128

1150,2

42111,548

19444,88

23710,752

1190,917

41964,715

18577,1

24318,72

1221,4536

,41674,3764

17768,9

25128,6

1262,1687

41635,3313

17006,286

25939,968

1302,8838

41643,3702

16350,748

26669,5296

13S9,5374

41680,7402

15725,736

27561,216

1384,324

41902,628

15147,249

28371,84

1425,0297

42094,0593

100

12783,58

31614,336

1679,4993

42718,4167

105

11078,56

39315,264

1974,684

48419,14

110

97()9,6

45394,944

2280,0476

52884,4964

115

8752,572

52690,56

2646,4838

58796,6482

120

7911,94

60796,8

3053,6352

65655,1048

It appears that about ^^ of the first quantity in the first co-
lumn should be added to it and to each of the succeeding num-
bers in that column, the quantity of water arising from the
steam itself being omitted. Mr Watt's idea seems to have been,
that, whatever might have been the temperature of the injected
water, that of the hot well should be invariable.

Let a — latent heat (960°) of vapour under ordinary circumstances.
b z= diiFerence between temp, of injected water and 212°.
c = diiFerence between temp, of hot well and injection.
d = quantity of water in steam used at each stroke.
e = area of air-pump piston.

./= total pressure of atmosphere on air-pump in lbs.
h ■=. area of steam-piston.

48 Mr Kenwood's account of the

Let i ■=. pressure of steam from water in hot well.

"' ^ ' ^J -\-h.i — e.i = effective resistance opposed to
ce

the operation of the engine, by atmospheric pressure on air-pump,

imperfection of vacuum, &c.

Tiiis leads us to a different conclusion from that at which Mr
Watt arrived, and shows us that the temperature of the injec-
tion water directly determines the temperature at which the re-
sistance is a minimum. The whole of the preceding investiga-
tion has been conducted on the idea that the steam whilst in the
cylinder absorbed no heat from the steam case, provided one be
used. But we have no correct data for calculating the increase
which must thus obtain. On the other hand, the higher the tem-
perature of the hot well, the less the quantity thus abstracted
from the case ; so that in practice the water in the hot well may,
with economy, be worked at between 95° and 100°. It may not
be altogether out of place to remark, that Mr Grose found his
engine at Huel Hope performed rather better when working J
than when at | expansive. The water passing into the con-
densing cistern may with economy be first passed over the
eduction pipe. The saw-dust placed around the cylinder and
steam-pipes is quickly charred, and, if not frequently removed,
will act on the iron, especially if it be not quite free from mois-
ture. It has been well observed that the only improvement
in the steam-engine since that of Mr Watt is in the dimen-
sions of the valves. At Huel Towan the valve which admits the
steam into the cylinder is 8 inches in diameter ; the equilibrium
valve 12 ; the exhausting valve 16. As the steam is usually
worked at about the pressure of 20 ft)S. on the square inch, the
weight on valves of such dimensions is very considerable. Many
contrivances have been made for obviating this inconvenience,
but the best yet invented is that of Mr Hornblower's, called
the skeleton valve, and described in Gregory's Mechanics. But
there is another recently invented by Mr Sims, a Cornish en-
jrineer, and extensively used by him in large engines. In
Plate I. Fig. 1, a a a^ a a, a" a!' is the seat, which at a a a
is solid. At & a apertures are cut in its sides for the pas-
sage of the steam ; and at a" a" is the beat, into which it is
ground with emery. The valve 6 6 is a plain cylinder, bored

PI^^^TB 1

lEAnv.JcuthofSa enceyol^

''^l Hlb

Steam- Engines in Cornwall. 43

very accurately ; c is the bar by which it is lifted. At dd it is
packed with the usual materials, e e is a ring by which the
packing is kept in its proper situation ; // is a second ring
resting on e e, and is kept in its place by the screws g g, by
means' of which also the packing is kept in a proper state of
compression. It is evident that the steam can exert no pres-
sure to prevent its being lifted ; nor when it is closed has the
vapour within any power to open it. It so completely answers
the purpose intended, that an infant might Hft the valves of a
90 inch engine. The packing is not a very desirable concomi-
tant, and it also increases the dimensions of the valve.

In the Philosophical Transactions for 1827, Mr Davies Gil-
bert, the illustrious President of the Royal Society, has pub-
lished some interesting observations on the steam-engine. But
in estimating the efficiency (/ X s) or force, multiplied into the
space through which it acts, he assumes both these functions
to be invariable. Now, in the present case, the value ofy is de-
pendent on the quantity of water evaporated by a given por-
tion of fuel. The writer of this has already shown that this is
in different engines very variable. The value of s must ([fric-
tion disregarded) depend on that of f. But if friction be in
operation, and has different amounts in various engines, we can-
not compare their efficiency until we reduce the value of fric-
tion to a determinate standard. But if the value of fhe like
in two instances, that of *, with the requisite correction for
friction, may be determined by the duty performed. And as
the ratio which s will bear to/ can be determined only by ex-
periment, it does not seem that we have any means of introdu-
cing the function f into the estimate of efficiency, without ma-
king friction another element ; consequently that duty and ef-
ficiency are identical, except when expansive working obtains,
and then the value of the advantage thus gained is the mea-
sure of their difference. Hence the duty is sometimes greater
than the efficiency, but never less. In calculating the duty of
a steam-engine, it is to be feared we cannot arrive at any very
accurate result, in the case of its being applied to spinning-ma-
chines, mills, &c. as our knowledge of the resistance opposed by
such apparatus is very limited. The only means of arriving at
any tolerable approximation appears to us to be, by ascertaining

44 Mr Kenwood's account of the

the average pressure of steam on the piston when the machine
is moving with its requisite velocity. This opinion is confirm-
ed by the knowledge, that the average performance of the ro-
tatory engines in Cornwall does not exceed seven millions, whilst
that of the pumping engines (in estimating the duty of which
no difficulty appears) is about thirty millions. That such a dif-
ference actually exists cannot be for one moment imagined.
The selection of one pound weight lifted one foot high, as a
dynamic unit, appears to have been very judicious. The term
efficiency seems so far useful, as its illustrious propounder had
intended ; but we think that consumption of fuel might also
be denominated expence of the efficient. Eighty-four appears
to us a very inconvenient unit. One pound would be much
more agreeable to our preconceived opinions of scientific order.
The only difference between the duty of a large and a small
engine, supposing them equally good, is only in the value of
the friction, which is inversely proportional to their dimen-
sions. Hence, supposing friction to vanish,

Let r zz resistance.

s zz space through which it is moved.
C = expence of the efficient.

Then — - duty.

Which under precisely similar circumstances, would be the
same for an engine of any dimensions ; the expence of the
efficient being always in proportion to the resistance overcome.

Steam-Engines in

Cornwall

A. tabular view of the performance of Steam-Engines drawing water out of the

mines in Cornwall.

I \

^ 1

•^

%^l

S ^

Mines.

Diameter

"si

"S .

'S'

3f cylinder.

$;§

-1

"is

J fi

!i.

, 3

0 3

p
0

° s

3
Q

C 3

0 3

^00

Dolcoath,

76 inches

"",■

single,

7,5

11,4

5,1 ^

t0,3 6,2 1^

10,5 (

>,7 36,615,5 j:

55,

J,3

36,4

7,1

58,5

Stray Park,

>4 inches

single,

5,5

4,3

28,6.

1,7

27,3

5,9

27,9:

5,4

27,2

5,7

25,7

6,2

27,5

Tin Croft,

fi6 inches

single,

6,8

32,6

7,4

33,7

5,5

32,9

5,3

33,1

Huel Char-

36 inches

lotte,

single.

6,25

3,8

1,9

13,1

Huel Vor,

63 inches

double,

6,25

17,2

7,8

25,

6,9

27,3

5,7

24,2

4,9

22,6

5,4

20,5

6,3

24,5

53 inches

single,

8,75

7,25

19,6

8,1

29,1

5,3

23,3

5,1

:29,9

27,6

4,6

31,7

7,2

37,6

48 inches

(59)

single.

7,75

5,5

10,7

7,1

37,3

8,7

41,1

8,4

38,7

6,4

31,6

4,8

27,2

5,8

29,5

45 inches

(3)

(60)

(85)

single.

6,75

5,25

15,3

8,1

3,04

5,2

28,

23,8

5,7

33,7

7,2

38,5

80 inches

(81)

single.

10,

7,5

11,3

37,7

42,3

44,

5,8

47,3

52,1

Crenver,

70 inches

(I)

(4)

(25)

single,

8,5

7,5

31,5

8,3

12,5

7,7

16,5

14,8

Oatfield,

70 inches
single,

8,5

7,5

6,6

7,9

(1)
28,3

Huel Abra.

66 inches

ham.

single,
45 inches

8,5

7,25

8,4

9,3

30,2
U)

(Woolf's)

great cyl.
60 inches

6,75

16,4

8,2

47,

(1)

(Woolf's)

great cyl.

8,75

7,25

12,3

6,9

25,

Huel Clow-

40 inches

(1)

ance.

single,
53 inches
single.

7,5

16,3
13,8

2,6

18,8

(I)

34,4

Carzise,

22 inches
single,
50 inches

4,75

23,2

14,1

25,4

13,2

21,3

(45)

(70)

single,

6,9

7,8

34,1

2,1

17,4

3,1

32,6

fi,

38,7

United

63 inches

(10^

Mines,

double,
63 inches
double,
65 inches
double,
63 inches

9,
9,5

8,
(2)

7,5

14,2
13,4
11,4

7,8
7,1

7,4

26,5

25,

18.2

5,9
5,2
6,2

26,2
(11
20,3

16,4
(12

(Sims's]

great cyl.

9,5

7,5

13,5

5,9

23,3

23,

Huel Unity.

53 inches

single.

6,6

5,75

10,2

3i,3

32,4

7,1

28,2

7,3

20,6

58 inches

(47

double,

7,4H

J 6,

14,1

5,3

22,6

5,7

21,7

5,7

21,2

5,2

24,4

5,7

24,6

7,1

27,5

Poldice, 190 inches

r27

(61

)

Jsingle,

10,

8,9

5,4

39,4

38,

5,8

36,2

4,8

35,7

5,6

37,9

46,1

Mr Kenwood's accou7it of the

R \l

s S

w •

• Im

-^ . 1 ^

Mines.

Diameter

"sl

of cylinder

•l-l

£S

s ^

"sS

•a -2

°°

60 inches

M-?,

° 3
II

_ 1

O 3

O p

6.S

<= 3

O.S

Poldice,

single,

10,

6,5

11,4

5,7

30,2

6,2

26,3

6,2

26,

4,8

18,£

5,6

23,8

30,

•iS inches

single,

5,5

4,5

6,9

5,25

11,4

Consolidat-

DO inches

(46)1

ed Mines,

single,
90 inches

9,96

7,5

9,5

6,3

40,6

5,6

36,7

6,9

33,9
(28)

5,7

33,4

5,2

37,5

7,6

50,1

single.

9,9 U

J 7,5

10,26

7,7

36,

33,4

9,1

28,6

7,9

30,1

6,6

41,7

5,2

39,

90 inches

single.

10,

7,5

7,4

4,7

64,3

4,1

61,f

70 inches

(3)

single,

10,

7,5

7,8

4,8

29,

6,1

39,7

6,6

42,£

70 inches

(96

single.

10,

7,5

7,2

1,6

14,9

2,9

28,8

4.7

44,4

58 inches

(13)

single,

7,75

6,5

14,9

3,4

28,3

5,9

28,8

25,9

5,5

27,9

4,2

38,6

5,8

39,9

Huel Dam-

42 inches

(2)

(62)

sel, (Sims's)

great cyl.
50 inches
single.

7,5

8,5

5,75
6,5

20,1
9,8

27,4

4,4

30,4

4,2

28,2

30,2

4,2
2,3

32,1

(3)

32,3

5,5
2,9

33,8
(89
33,3

Ting Tang,

63 inches

(14)

(29)

(48)

(63)

(88

single.

7,75

6,75

9,3

27,7

6,2

31,2

5,6

34,6

6,3

35,5

7,3

37,3

7,6

35,2

Tresavean,

60 inches

(15)

(64)

single,

5,3

3,9

23,7

3,1

20,9

3,3

21,3

3,2

19,4

3,6

19,8

3,9

22,6

Huel Bui-

36 inches

(16)

(30)

ler.

single.

7,75

5,75

8,4

3,6

20,2

3,7

21,9

3,9

20,8

3,2

19,8

3,9

21,6

22,2

Huel Bas-

24 inches

(17)

(31)

set,

single.

7,5

5,5

9,5

9,1

19,6

10,7

19,7

17,6

8,9

16,3

Huel Har-

36 inches

mony,

double,
70 inches

0,666

28,

24,1

(56)

(83)

single.

9,25

7,4

6,8

35,2

8,8

34,5

4,5

26,5

4,5

28,7

6,2

30,5

Huel Mon.

50 inches

tague.

single.

8,666

G,75

6,5

6,1

21,7

Huel

63 inches

(3)

Squire,

single.

12,2

5,6

26,6

«,4

24,4

Treskerby,

58 inches

(2)

(Sims's)

great cyl.
50 inches

7,75

14,7

5,7

38,4

8,2

38,8

7,1 '

37,9

7,5

36,9

7,6

41,1

9,1 ^

12,3

louble.

7,583

5,75

18,4

3,8

25,3

4,1

25,9

2,4 '

22,5

Huel

45 inches

Chance,

(2)

(65)

(Sims's)

great cyl.

7.916

17,2

3,3

28,6

7,2

30,1

5, 5

29,2,

5,2

30,2

1,5 i

25,9

5,4 2

'9,3

CardreW,

27 inches

(18)

(66)

double.

7,853

5,75

7,2

17,8

12,1

),2 ■:

24,4 1

),7

17,7

3,6 5

Jl,

2,3-2

^, '

West Huel

45 inches

(1)

(8)

Alfred,

single,
70 inches
single.

9,
9,5

7,
5,5

12,1
5,75

10,4

25,7

10,1
J,8

24,7
27,1 '

?,8 •:

r,8 i

J4,
7,6

Penberthy

64 inches

Croft,

single.

9,25

7,23

5,9 <

J,7

26,1

HuelReeth,

36 inches

(9)

(33)

(76)

single.

7,5

11,4 :

1,5

26,8 I

},8

28,4 i

\,l i

»5,4 S

5,5 S

25,4;

J,9 2

9,1 ^

,3 2

3,2

St Ives Con-

20 inches

(24)

(34)

(77)

(3)

sols, \

single, j

6, 1

3,9 1

0,7 |S

J4, i

>,2

n,4 3

r,4 s

»3,9f

»,5 J

25,2 ^

i,4 a

0, i

;,9 2

8,8

IB'

Steam

-Engines in

Cornwall

(

: Mines.

Diameter

of cylinder

■s s

.s ^

"«^

'2i

■s^

•si

CO,

W)3

i's

6.1

O 3

o.S

6.5

° 3

6.3

O 3

6.S

° 3

O.S

t^'

3.S

►3.S

^.s

iziS

Unbo,

58 inches

single.

8,5

5,2

7,4

16,8

iael Speed.

36 inches

(5^

^well.

single,

8,8

28,3

6,4

27,3

27,1

HNoiiis,

53 inches

(29:

(35)

(49)

(78)

single.

8,5

7,25

5,5

4,4

24,1

27,8

5,5

26,9

4,3

27,6

4,3

29,6

5,2

29,4

w- '

56 inches

(3)

(87)

single.

6,75

6,7

4,8

26,4

5.4

24,1

KpQbroke,

60 inches
single,
45 inches
double,
80 inches

8,411
8,75

6,25
6,75

9,1
19,3

4,6
4,8

24,3
28,3

4,4
5,1

20,7
24,8

(42)

single.

10,25

7,25

8,6

6,1

32,8

5,5

36,

4,3

37,9

4,3

37,3

5,5

42,5

K''

40 inches

single.

6,5

6,1

2,3

23,1

Wast Crin-

60 inches

(20)

(43)

(79)

nis,

single,
70 inches

5,588

55,

11,7

24,
(3)

5,9

25,2

(21)

4,8

23.7

(40)

4,2

16,6

5,4

21,5

5,5

21,2

single.

10,

2,9

13,9

4,9

33,

4,1

28,7

4,5

31,2

5,3

31,9

36,2

Huel Rose,

45 inches

(22)

(44)

(80)

single.

15,2

9,3

33,4

7,2

30,

5,7

30,

5,6

26,2

6,6

27,8

9,6

36,

Barton,

40 inches

(1)

(23)

(36)

single.

8,5

6,75

6,6

28,6i

10,4

29,3

8,9

37,4

West Huel

50 inches

(3)

Rose,

single.

8,6

17,5

Herland,

80 inches

(3)

(6)

(50)

(1)

single.

8,833

3,2

12,

26,3

7,1

36,

36,3

4,2

39,1

4,3

35,

80 inches

(3)

(7)

(51)

(3)

single.

8,833

3,4

10,1

20,2

5,9

33,4

4,2

37,7

4,8

40,3

6,2

36,6

Binner

63 inches

(26)

(52)

(82)

Down,

single,
40 inches

7,5

14,6

10,1

30,2

8,1

37,1

9,6

35,3

10,3

36,9

(68)

10,

32,7

single.

6,5

6,6

19,7

6,8

18,6

4,8

30,2

7,8

40,6

70 inches

(71)

single.

10,

6,1

6,8

37,

9,1

40,9

8,5

55,5

United

90 inches

(38)

Mines,

single.
30 inches
single,

8,75
9,

7,75
8,

16,5
12,9

7,3

28,1

5,6

35.7

3,4

34,5

3,8

6,7

34,9
26,1

6,8
6,3

35,9
32,5

Huel Went-

45 inches

worth.

(Woolf's)

great cyl.

7,1

4,5

28,6

3,8

27,6

Great St

60 inches

(39)

(84)

George,

single,

8,333

6,25

6,1

32,4

5,6

29,

5,8

31,

6,1

33,4

6,6

33,6

Huel Busy,

66 inches
single,
70 inches

10,

11,5

23,5

3,8

31,6

(90)
44,4

single,

9,75

7,25

10,1

4,2

34,3

2,9

29,8

5,3

34,8

5,7

39,7

8,3

Polgooth,

80 inches

(37)

(41)

Jingle,

10,25

7,25

7,4

10,5

42,1

10,3

41,3

11,6

42,2

South Huel

26 inches

Treasure,

.ingle,

2,87

3,9

9,4

Huel Fosw .

j3 inches

ter,

.ingle, 1

3,333('

7,2 I

9,7

26,81

7,2

30,6

6,1

28,5

7,5

26,6

Mr Kenwood's account of the

Mines.

Huel Pros-

per,
Condurrow,

Huel Pen-

rose,
Huel Hope,

Huel Al-

fred,

(Woolfs)
Lamin,

Silver HUI,

Huel Tol-

Huel Spar-
non,

Pednan-
drea,

North
Downs,

East Huel
Basset,

Poladras
Down,

Huel Wel-
lington,

Huel For-
tune,

Huel Caro-
line,

Huel Tre.
voole,

Great
Work,

United
Hills,

Huel Mai-
den,

Balnoon,

East Huel
Unity,

Perran
Mines,

Lelant Con-
sols,

Huel Pen-
with,

Huel
Towan,

Diameter
of cylinder

53 inches
single,
40 inches

ingle,
3G inches
single,
6o inches
single,
52 inches
single,
90 inches
single,
70 inches
iJjreat cyl.

5 inches
single,
30 inches
single,
25 inches
single,
70 inches
single,
70 inches
single,
70 inches
single,
50 inches
single,
70 inches
single,
28 inches
ingle,
45 inches
single,
30 inches
ingle,
30 inches
single,
GO inches
single,
58 inches
single,
63 inches
single,
30 inches
single,
45 inches
single,
38 inches
single,
15 inches
single,
40 inches
single,
80 inches
single,
80 inches
single,

^ s

7,
9,
8,5

7,GGG

10,

7,5

10,

9,833

8,75

9,5

6,5

7,75

7,5

8,25

10,

8,75

6,75

7,5

8,75

10,

5)3

a S.

6,6

6,75

7,5

5,5

7,5

7,75

6,75

7,25

5,75

6,5

7,5

6,75

4,5

ea o

4,76

3,9

5,13

5,38

12,4

6,48

14,6

9,9

4,93

17,2

8,88

9,7

7,9

8,6

7,1

13,9

6,46

7,29

9,7

11,8

6,2

13,7

5,6

8,38

14,27

12,3

3,75

4,56

9,36

4,9

22,

2,6

3,2

5,6

5,4

5,3

5,6

5,8

4,1

6,8

3,5

4,7

24,

13,6

17,7

40,8

27,8

41,9

39,9

22,2

17,7

19,

38,2

30,4

29,4

21,
3,8
6,3
5,6
5,1
4,2

6,3

5,8

3,5

3,9

7,1

1,8

8,1

5,9

9,4

10,4

3,8

(55)
14,4

(54)
21,1

(53)
45,4

42,1

30,8

40.4

18,4

23,8

(57)
37,3
(58)
33,7

30,6

33,1

(41)
20,8

1,9
5,6
6,3

(3)
11,6
(69)
23,7

47,3

7,3

(91)
29,8

(92)
70,

6,4

(3)
35,6

33,6

31,7

20,5

23,6
(1)

25,6
(1)

24,7
(3)

24,3

3,4
8,1
7,2
9,8
6,1
4,2
3,2

3,2
3,8
6,5

3,6
7,3

32,6

(67)
21,4

(72)
25,7

(73)
25,7

(74)
26,4

(75)
34,9

6,1

(3)
19,

15,2
(3)
26,

48,9
58,1

8,8

10,9

8,8

7,4

3,7

5,6

3,3

5,4

7,2

3,1

6,5

6,8

32,4

37,9

(93)
n,6
(94)

27,5
(95)

39,8

36,
23,1

19,2

23,5

(86)
24,7
(41)
12,3
(41)
16,2

50,

77,1

Steam Eiigines in Cornwall,

1 4 months only.

2 On Sims's construction.

3 2 months only

4 Load reduced to

2,6

5 augmented to

16,8

7,1

8 diminished to

7,«

9 augmented to

12,5

19,

17,1

12 1

( and put to work

16,9

single.

13 Load augmented to 17,1

12,*76

4,7

11,7

11,1

1J,6

6,6

15,1

5,3

22 diminished to

11,7

23 augmented to

8,7

18,4

3,7

16,7

10,

29 diminished to

11,1

30 augmented to

13,2

11,1

8,2

NOTES.

33 Load augmented to 14,4
34

diminished to

augmented to

diminished to

augmented to

25,
10,9

7,4

4,69

7,9

10,3

6,9

For one month only.

42 Load augmented to 11,3

43 diminished to 4,2

44 augmented to 15.7

45 diminished to 3,

46 5,9
altered to single.

48 Load augmented to 13,2

49
50
51

52 diminished to

53 augmented to
54

56 diminished to

58 augmented to

69 diminished to

60 augmented to

63 diminished to

64 augmented to

14,8
11,9

9.
12,5

7,4
7,25

6,4

6,
10,5

7,9
11,7
11,5
21,5

9,5

6,2

65 Loud augmented

reduced to
augmented to
reduced to
85 augmented to

87
88
89
90
91
92
93
94
95
96

diminished to
augmented to

to 20,1

24,7

15,7

10,

9,9

6,6

10,1

9,1

21,8

14,3

8,9

16,2

14,5

16,6

9,4

18,9

14,2

8,2

6,1

9,4

12,6

16,4

9,6

14,2

8,2

11,4

11,2

9,4

10,2

24,2

20,1

8,5

It has been before observed that the engine reports are de-
ficient in some important respects.

In 1823 there were 55 engines at work in Cornwall,
performing on an average 26,9 miUions.

1824, 57 28,

1825, 62 28,97

1826, 63 28,36

1827, 62 31,9

1828, 60 ^34,85

VOL. X. NO. I. JAN. 1829.

50 M. Becquerel on the electrical proj)erties of Tourmaline,

Art. VIII. — 071 the Electrical Froperties of the Tourmaline.*
By M. Becquerel.

Jl HiLOSOPHEKS attribute to molecular attraction an electrical
origin, though they are still ignorant where the electrical forces
reside by which it is produced. Among the hypotheses, more
or less ingenious, contrived for explaining this mystery, there
is one which considers the atoms of bodies to be endowed with
electrical properties analogous to those which heat developes in
the tourmaline. This manner of viewing it rests solely upon
conjecture ; and in order to verify it, since we cainiot isolate an
atom in order to study its physical properties, we must exa-
mine with the utmost care all the electrical modifications which
the tourmaline exhibits when its temperature is varied, as well
as the laws which regulate them, and see if it be not possible
to draw inferences more or less favourable to an electro-che-
mical theory. Such is the philosophical object which I had in
view in the researches which I have undertaken upon the tour-
maline.

The electrical properties of this remarkable stone have for
a long time engaged much attention. Some philosophers have
even asserted that it was known to the ancients under the name
of Lyncurium, given to it by Theophrastus ; but upon examin-
ing with attention the characters assigned to it by this philoso-
pher, we can find none which belong to it in particular. It is
known for certain, however, that from time immemorial it was
observed in India and in the Island of Ceylon, that this stone,
when thrown into the fire, had the property of attracting the
cinders. The Dutch, to whom the natives of the country
showed the phenomenon, were the first who made it known in
Europe. Lemery, in 1717, presented to the Academy of Sci-
ences a tourmaline brought from Ceylon, which possessed the
property, he said, of attracting and repelling light bodies.
More recently the Duke of Noya, iEpinus, Wilson, Priestley
and other philosophers examined the attractive power of this
stone. Many of them obtained contradictory results, which

• Read to the Royal Academy of Sciences, 14th Jan. 1828. Translated
from the Annales de Chimie, Jan. 1828. torn, xxxvii, p. 1. See this Jour-
nal, No. 16, p. 365.

M. Becquerel on the electrical properties of Tourmaline. 51

were the subjects of very long discussions. It was thus that
^pinus asserted, that if, one side was heated more than the
other, they each acquired an electricity opposite to that which
was natural to them ; while Wilson maintained, that, when the
sides of the tourmaline were heated unequally, that side which
had the highest temperature took the electricity which was pro-
per to it, and transmitted it to the other side. A contradiction
so palpable must result from a difference in the manner of
making the experiments. They attempted to remove it by
making new experiments, but not succeeding, they each thought
they were in fhe right, and employed themselves no longer on
the question, which since then has ceased to attract the atten-
tion of natural philosophers.

At that period tourmalines, which were only procured in
India, were rare in Europe ; and hence the same stone passed
in succession through the hands of Canton, ^pinus, and Priest-
ley, in order to study its properties. At present they are very
common, since the discovery of a stratum in Spain which con-
tained a great quantity of them. Canton, in a paper read to
the Royal Society of London in December 1759, asserted, to
use his own expression, that the tourmaline neither emits nor
absorbs the electrical fluid but by the increase or diminution
of the heat. This fact, which should have fixed the attention
of philosophers, has been entirely forgotten.

The same philosopher has added another important fact to
the theory of the tourmaline, by showing, that, if a crystal is
broken at the moment when it is electrical, each piece possesses
equally two poles, in such a way that the two separate parts
are in two different electrical states. He has also discovered
that the topaz of the Brazils, and many other crystallized
mineral substances, possess electrical properties analogous to
those of the tourmaline. In the treatises on natural philosophy
there is very little said about the tourmaline. Even M. Haiiy,
who attaches great importance to the physical characters of
mineral substances, on account of the application which he made
of it to mineralogy, his favourite science, has given but an
incomplete theory of the tourmaline. He has, however, discover-
ed one important fact, that the crystals which derogate from

5J^ M. Becquerel on the electrical properties of Tourmaline.

the laws of symmetry in the configuration of their summits are
electrical by heat.

I have thus, I presume, given a summary of all that has been
observed respecting the properties of the tourmaline down to
the present time.

I commenced my inquiries by observing what took place in
a tourmaline, 1^^, when all its parts were equally heated or
cooled at the same time: Sid, when one of the sides received
more heat than the other, whether this heat was increasing or
decreasing. I first suspended the stone in paper by a single
silk fibre, which descends into a glass vessel placed in a basin of
iron filled with mercury, and the temperature was then raised
by a spirit-lamp, upon which it was placed. In proportion as
the interior of the vessel became heated, the temperature of the
tourmaline was raised, and, as it was very easily set in motion
from its mode of suspension, the slightest signs of electricity
were quickly observed. A thermometer placed at a short dis-
tance from the tourmaline indicated its temperature. With
this apparatus I obtained the following results : At 30° Centi-
grade, the electrical polarity began to be sensible at the ap-
proach of a feebly electrified body, and it continued as far as 150°,
and beyond it, provided the temperature continued to rise; for if
it was stationary an instant the polarity disappeared immediate-
ly, so that there was no appearance of electricity as long as the
temperature was constant ; but the moment it diminished, the
polarity reappeared, but of an opposite character. The pole
which was originally positive became negative, and vice versa.
These effects always took place at whatever time the elevation
of the temperature was arrested. The time of the passage from
one polarity to another was very short.

From this one would think, that the electrical intensity of
each pole was proportioned to the quickness of the heating or
of the cooling ; but it does not appear to be so. In order to
observe what will happen, it is necessary to measure tlie elec-
trical intensity at any epoch whatever. This is done by placing in
the interior of the vessel of glass containing the tourmaline, and
at a little distance from each of its extremities, two vertical rods
of iron, each communicating with one of the poles of a dry
pile^ whose electrical intensity may be considered as constant,

M. BecquGrelo/^ the electrical properties of Tourmaline. 53

during the space of one hour, especially if care be taken to
keep it from the action of heat.

As soon as the tourmahne is become electrical, it is placed
between the two rods, the opposite poles being placed together;
and if it is shifted from this position, it returns by a series of
oscillations, of ^yhich the number in a given time will serve to
determine the intensity of the electricity. The following table
contains several results : —

Temperature
of the Tourmaline.

100

Duration
of the oscillations.

Number
of the oscillations.

90
80

10
13

70
60

30
30

15
15

The temperature had been raised to 115° ; at 105° the tour-
maline, although it had been electrical before, began to fix it-
self between the two vertical rods which communicated with
the dry pile ; at 100° the oscillations were measureable. The
preceding results prove that from 115° to 100°, the time when
the cooling is the greatest, the electrical intensity increases very
slowly; that from 100° to 70° the increase is rapid ; that from
70° to 40^ it is stationary ; from 40° to 20° it diminishes nearly in
the same proportion at which it had increased from 100° to 70°.
The electrical polarity disappeared altogether at 15°, although
it had began at 30°. Several tourmalines have given similar
results. We see, then, that the electrical intensity of each pole
is not caused by the suddenness of the cooling. If it is easy
to measure the electrical intensity of the tourmaline during
its cooling, it is not so during the elevation of the temperature;
for although the polarity be then sufficiently strong, it is not,
however, strong enough to enable us to determine the difference
of intensity which arises from the increase of temperature, by
employing the method of oscillations.

Hence we see that there exists a marked difference between

54 M. Becquerel on the electrical properties of Tourmaline,

the mode of action of the developement of electricity during
the increase of temperature, and that which takes place during
the cooling. In both cases the temperature varies every in-
stant.

The most delicate experiments seem to show that the tour-
maline, while it is electrified, allows none of the electricity to
escape, nor takes any from surrounding bodies. The effects
are produced by the separation of the two fluids in each par-
ticle. In order to prove that there is no discharge of electri-
city from the tourmaline, it is necessary to place upon the up-
per plate of an excellent condenser of Volta, a plate-of copper
of a high temperature, and place it below one of the extremities
of the stone. Some moments after, upon separating the plates,
no accumulation of electricity will be found.

After having studied what passes in a tourmaline of which
all the parts are equally heated and cooled at the same time,
I now proceed to examine what takes place when one of the
sides receives more heat than the other.

iEpinus and Wilson, as I said before, were much occupied
with this question. The contradictory results at which they
arrived may be easily explained. To analyse the electrical ef-
fects which are exhibited, we must first of all observe if the
temperature is increasing or decreasing in the side where it is
applied ; for the results vary in each case. This is known by
inclosing each end of the tourmaline in a little tube of glass,
the ends of which are melted by the blowpipe that they may
fit exactly ; it is then fastened by its middle to a tube of glass
by a thread of platina. If one of the extremities which is not
fitted in one of the little tubes be heated, for instance that which
corresponds to the side positive by cooling when the tempe-
rature is everywhere the same, and which I represent by P,
this side will at first be heated at the expence of the tube, will
take the same temperature as it, and will then cool in the same
time. In the first case, whilst the temperature does not begin
to rise at the other extremity, which I call N, all that part P
will be electrified negatively, and the other will be in the state
of zero. The tourmaline then possesses but a single electricity.
We know this by presenting successively all the points of the
tourmaline to the little tinsel discs of the electroscope of Cou-

M. Becquerel on the electrical propertiea of Tourmaline, B5

lomb, charged alternately with positive electricity and negative
electricity.

Its state of electricity is then sensibly the same as that of a
Voltaic pile of which the positive pole is in communication
with the earth ; because the negative electricity goes on dimi-
nishing to the opposite pole. This effect is only produced when
the temperature goes on decreasing, and the side opposite to
that which has been heated has not attained sufficient tempe-
rature to develope also electricity. In the pile only one sort of
electricity is obtained every time that one of the poles com-
municates with the common reservoir ; it is not so, however,
with the tourmaline, which neither gives out electricity nor
takes it from surrounding bodies. This fact is in contradiction
to our present knowledge of the developement of electricity,
which is never found except in two fluids. It follows, then,
that in this case there must be one masked or absorbed by
the air. but I have never found this indicated by the most
delicate observations. It is certain, however, that a single kind
of electricity can be produced from one of the sides of a tour-
maline without the other acquiring any ; and consequently,
without our considering the state of this last as transitory, that
is to say, passing from one electrical state to another.

I have supposed that the side N had not yet acquired a
sufficient temperature to produce any electrical effects ; but if
it continued to increase, the side would acquire the positive
electricity which it should have had if the temperature had
been equally increasing in the whole tourmaline-

I return now to the side P, whose temperature I have sup-
posed to be increasing. As soon as it is become stationary its
electricity ceases, and afterwards begins again in an opposite
direction, when it decreases. At the same time, the side N, ac-
cording to the temperature, will be at zero, or possessing elec-
tricity positive or negative. I conclude from all these facts,
that when the two sides of a tourmaline are heated unequally,
each of the two acquires an electrical state independent of the
other, and is such, that, if the side P for instance has a tem-
p^ature at first increasing, then stationary and decreasing, it
will become negative, zero, and positive. The side N, under
the same circumstances, that is, if its temperature be increasing,
stationary or decreasing, will have a contrary electricity. The

66 Mr W. M. Rice's account of an ancient Vessel

electrical state of each side then will be the same as if all the
stone possessed the temperature corresponding to this side.

I have examined before a case where the temperature was
increasing at the extremity of the side P, and stationary at the
opposite end. To accomplish this we must put the end N into
a httle tube filled with ice, and cemented to the tourmaline.

After the facts which I have related, we cannot explain
chemical actions by admitting in the atoms electrical proper-
ties analogous to those which heat developes in the tourma-
line ; for as electrical polarity does not exist but when there
is an elevation or diminution of the temperature, the combi-
nations would cease of themselves at the moment when the tem-
perature becomes stationary. By supposing even a permanent
polarity in the atoms, we cannot see how the electrical modifi-
cations by the increase of heat, analogous to those which are
observed in the tourmaline, could produce the effects due to
affinity.

I do not pretend to explain in this paper how the atoms
become electrical, or if they possess a permanent electricity.
My object has been to study the electrical properties of the
tourmaline, and to prove that it is not possible to establish an
electro-chemical theory, by considering the atoms of bodies
like little tourmalines, or possessed of analogous properties.

Since writing this paper, I have heard of a work of Berg-
man upon the tourmaline, which has been nearly forgotten. I
shall speak of it in my next paper, in which I shall explain
some new researches.

Art. IX. — Account of an Ancient Vessel recently found under
the old Bed of the river Mother in Kent, and containing the
bones of men and animals. In a Letter. from William
M'Pherson Rice, Esq. F. S. A. late of the College of
Naval Architecture at Portsmouth, addressed to Henry
Ellis, Esq. F. R. S. Secretary. *

The late discovery of a vessel under the ancient bed of the
river Rother having given rise to various conjectures and con-
tradictory statements, respecting her age and former service,

• From the Archaeologiay vol. xx. p. 553, Lond. 1824.

found under the old bed of the rwer Rother. 57

and the subject being of some interest in naval architecture, I
was directed by Sir Byam Martin, at the request of Lord Mel-
ville, to repair to the place where she was found, and to obtain
a true account of her build and situation, in order, if possible,
to ascertain the country she belonged to, and the period of her
submersion. My report has been subsequently transmitted
to the Admiralty ; and, at the suggestion of Mr Barrow, T have
taken the liberty of addressing to you a letter, containing the
substance of that report ; and should the subject be compatible
with the regulations as to papers usually read at the Society
of Antiquaries, it will afford me much satisfaction if you will
do me the favour to introduce it at the ensuing meeting.

The site of the vessel is in the level of East Matham, in
Kent, near Matham Wharf, under the bank of a stream or
sewer, running into the present river Rother, to the west of
the Island of Oxney. She was accidentally discovered, and sub-
sequently dug out, by a person of the name of Elphee, a poor
man in the employ of J. Pomfret, Esq. to whom the adjoining
land belongs, and with whose permission, and the sanction of
the Commissioners of Sewers, the excavation was undertaken.

Mr Elphee informed me, that part of the covering to the
after-cabin used to be Visible in the side of the bank, when the
water in the channel was very low, and about six years ago he
took some plankilig up (thinking at that time that it had been
part of an old sheep-wash), which he applied to the repairs of
a cart-shed, and some paling ; and in the early part of July last,
having occasion for some wood for a similar purpose, he drew
up a piece, which, from its shape and peculiar fastening, led
him to imagine that a vessel must have been sunk there. Having
confirmed the surmise by partially digging along the bank, he
communicated the discovery to several gentlemen, by whose ad-
vice and assurance that he should be at no risk of loss in the
event of its proving a bad undertaking, he dammed up the
channel, and commenced the work ; and in a few days, after
digging through ten feet of sea sand, the whole of the vessel
was exposed. See Plate I. Fig. 2.

Her principal dimensions are as follow : —

ft. in.
Length - - - - - - 63 8

-4 • •

58 Mr W. M. Rice''s account of an ancient Vessel

ft. in.

Breadth - - - - - - 15 0

Height of foremost beam from flat of inside 'planking, 4 11

Height of midship beam from the same, - - 4 2

Height of the after beam, - - - - 4 7

Height of the bulwark above the beams, - - 1 2
above which were wash-boards.

She is built entirely of oak, which is perfectly sound, and
very hard, but much blackened ; her head and stern are sound,
and framed nearly alike, but in a very rude manner ; stem and
sternpost nearly upright ; flat-floored, and clinker built. The
planks riveted together with iron, and fastened to the timbers
with oak treenails, wedged at both ends with wood of the same
nature, which is now quite as hard as, and bears much the ap-
pearance of ebony. The planks, inside and out, are If inch-
thick, and some of them of surprising dimensions ; one on the
starboard side, forward, is 18 feet 10 inches long, 2 feet 5 inches
broad at the fore-end, and 1 foot 9 inches at the after-end ; an-
other, on the larboard side aft, is 18 feet 7 inches in length,
and 2 feet 5 inches and 2 feet 7 inches broad at its extremities,
and from its texture certainly not of British growth.

The beams, of which there are five principal ones, are very
ingeniously scarphed and put together, and fastened to the sides
with bolts, not unlike our "dog bolts," exceptmg that the plate
is secured to the beam with staples instead of bolts ; their mean
scantling is 5| by 1 foot 6 inches.

There is a step for a mast, at about one-third of her length
from forward, on the foreside of the beam ; but no part of the
mast has been discovered ; there is evident proof also that she
had had a bowsprit, which has been carried away, the step be-
ing visible in the foremost beam, and the head of the stem a
little hollowed as a bed ; the cable passed over the gunwale,
the grooves for which are not much rubbed ; neither cable nor
anchor have been found ; some pieces of cordage were taken
out of the after-cabin, in a very decayed state, the strands of
which appeared to have been laid in the manner at present
practised.

The caulking material is moss, and the sides of the vessel
are payed with a thick coat of tar or some composition, which,

found under the old bed of the river Rother. 59

since its exposure to the atmosphere, is entirely decomposed,
and falls off as dust on the slightest touch ; the seams and pro-
jecting edges of the planks are filled with pitch, which remains
almost in its original state. The iron which has been exposed
to the action of moisture is very much enlarged by oxidation,
and breaks with facility, but in all cases where covered with
pitch, it is most perfect, and not in the least corroded. This is
an important fact.

It is much to be regretted that many of the contrivances and
fittings have been disturbed, and either destroyed, or so mu-
tilated as to make it impossible to restore her to the state in
which she was first found. There were originally two short
decks ; the one aft remains, that forward has been taken up ;
the opening between the deck aft and the next beam was co-
vered with a kind of arched tilt, beneath which was probably
the place for cooking, from the situation of the fire-place and
the utensils found there.

The space between the after-beam and the deck forward
was open ; but several stanchions were found standing morticed
upon the beams, from which it is obvious that there had been
a covering over this part of the vessel also ; and from some ra-
betted boards inclining inwards and upwards, still attached to
the sides, we may conclude, that the covering was either atched,
or met at an angle in the centre like a roof.

There are carlings at the sides, and scores in the beams in
midships, evidently to receive a covering, but no gratings or
hatches have been found.

The manner in which the rudder was managed is rather cu-
rious, and I owe it to chance that I discovered the method. In
examining some pieces of wood which had been taken from the
vessel, I observed a beam of singular construction that had
been removed from the topside aft, and by some bevelling scores
in its ends it was clear that a plank sheer had dropped into
them, which was afterwards found and replaced.

A dumb roller is turned upon the middle of the beam, and
on each side of the sternpost, and at about a foot below the
gunwale are two holes through the side of the vessel, and one
also in the after part of the rudder, through which most pro-
bably the rudder was yoked. I cannot tell exactly in what way

60 Mr W. M. Rice's accottnt of an ancient Vessel

the fall of the steering-rope was traversed, but I imagine there
were two distinct ropes, a round turn being made over the rol-
ler with the one by which the rudder was governed.

The vessel was floated on the 27th of August. I was on
the spot at the time, and in digging a water course towards the
dam in the channel abaft her, to admit water into the basin
formed by the excavation, a small boat was discovered at about
sixteen feet from the stern of the vessel. She appeared to
be a wreck, the after part being gone. I ascertained the di-
mensions of this boat as nearly as I could ; (the water was at
this time flowing in from the channel forward) ; her length
was about 15 feet, breadth 5 feet, flat floored, and very shallow;
the timbers very stout, and few in number; they were gene-
rally about 3 feet apart; the planks from |to 1 inch and J thick;
clinker built, and fastenedwith iron rivets, and no inner shea-
thing. The seams were caulked with /^a^r,* which is not in
the least perished ; the wood is also in a high state of preser-
vation, but very black. She fell to pieces on attempting to re-
move her.

From what has been now stated. Sir, there will be no diffi-
culty in pointing out the country she belonged to. The hous-
ing, or roof spoken of, is, I believe, although common to barges
of all countries, more peculiar to the Dutch.

The Earl of Romney, whom I met at the vessel, did me
the favour to mention several peculiarities which he had obser-
ved about her, when she was first opened, and which I should
otherwise have been ignorant of, as many of them were de-
stroyed prior to my seeing her. He pointed out the situation of

* When on duty at Sheerness dock-yard, I collected several specimens
of wood taken fron; the old ships which have been dug out in the progress
of the works carrying on there ; and it may, perhaps, be worthy of remark,
that among them I found a piece of oak plank with some hair adhering to
its edge, — a proof that hair had been used as the caulking material for that
ship. I have not been able to ascertain if she was of English or foreign build;
but Mr John Knowles of the Navy Office obligingly informed me, that
these ships were laid aground in the tim.e of Charles H. and in one or two
subsequent reigns, and served, some as break- waters, and others as resi-
dences for the artificers employed in that establishment, which was then
in its infancy : and we find that in his work on the " Preservation ef the
Navy," that hair was used in caulking for a long series of years in his
Majesty's Navy, and was not discontinued till 1791.

found under the old bed of the river Rother. 61

some rings just abaft the mast, on each side of the vessel, to
which the straps of the dead eyes were fastened. This mode
of securing the dead eyes is pecuhar to Dutch vessels.

His Lordship thought she resembled the build of the Ham-
burgh keels, and observed, that " moss is frequently used as
the caulking material in the East country ships."

A hand-lead having been found in her, renders it probable
that she had been a sea-going vessel ; and from the situation
of the mast-step, it is reasonable to conclude that the mast was
fixed ; under such circumstances, she could not have been for
inland navigation.

From these facts, and from several articles found in her of
Dutch manufacture, particularly some rude earthen vases and
tiles (which formed the fire hearth), there was little reason to
doubt that she was Dutch ; but there is nothing in her form,
nor has there been any thing found in her, with the exception
of the handle and hilt of a sword, that would create a suspicion
that she had been a vessel of warfare.

It may perhaps be worthy of observation, that ancient ves-
sels were usually propelled by oars as well as sails ; and we
find also that galleys were in common use in the reign of Henry
VIII. and even up to the time of James I. The vessel in
question is of a totally diff*erent construction, and shows no
signs of having been rowed ; but no inference can be drawn
from this as to date, since galleys were not the only description
of vessels in use. Concluding, therefore, that she was a Dutch
TRADING VESSEL, it bccomcs difficult to form any idea of her
age from the style of her architecture, which, for this kind of
vessel, admits of but little variation ; and which probably has not
materially changed for ages, whilst the contour and equipment
of fighting vessels must necessarily have varied with the modes
of warfare. . -.. >

Amongst the sketches which I have forwarded for your in-
spection, permit me. Sir, to direct your attention to the repre-
sentation of ablate of hard lead or pewter, which was attached
to the side of the vessel, at about 15 feet from her stern, bear-
ing two characters (pi) of the black letter, very neatly and dis-
tinctly stamped. A similar plate was found on the opposite
side, but so much oxidated and battered, that it was impossible
to decipher the characters on it.

62 Mr W. M. Rice's account of an ancient Vessel

The lines on a piece of oak slab are very curious, and pro-
bably a merchant''s mark ; but I am at a loss to know if it con-
sists of definable letters or characters, or merely hierosjlyphics.

Various articles were found in the after-cabin : such as a cir-
cular board of oak, with twenty-eight holes through it, which
probably had been used as an almanack or score table ; two
earthen vases of a reddish brown colour, glazed inside, and
standing upon three feet, and of the capacity of 5 pints each ;
another vase of a dark slate colour, with similar legs, unglazed,
and about the measure of 1 7 pints ; all of which had evidently
been used on the fire for cooking: a stone jug, very rudely
formed, holding rather more than a pint ; several bricks of cu-
rious manufacture, and some pieces of glazed and ornamented
tiles, set up as a fire-hearth ; a sounding-lead of an octangular
form, about eight inches long; and a small glass bottle of an-
cient and singular shape, 3 inches in height.

Some human and other bones were found in the cabin ; and
part of the skull of a child, with a thigh and several smaller bones
have been preserved, together with parts of a skeleton of a
grown person. In the midship part were found the thigh and
leg bones, and several vertebrae of the back-bone of some large
animal, thought to be a horse or cow, the horns and part of the
skull of a sheep or goat, and the lower jav^bone of a boar, with
its teeth and tusk ; no other part of this last animal was found,
so that most probably these were a part of the provisions of
the vessel, as also the breast-bone of some large bird. Near the
vessel, in the sand, was dug up a human skull, very black, with
other parts of a skeleton ; and by the side of it, the skeleton of a
dog, the skull and a few small bones of which have been pre-
served.

Several shoes or sandals were found, both in and round about
the vessel; among which is a child's slipper, of an unusual
shape, with a cork sole ; but of the various articles found of
this kind there are none which give a clue to any date.*

• The finding of this slipper has by some persons been adduced in ar-
gument against the vessel's antiquity ; but it is well known that cork was
used for this purpose among the Romans in winter. Pliny says, the wo-
men more especially used cork soles in winter: —

** Usus prteterea in hiberno femindrum calccatu.'

found under the old bed of the river Rother. 63

At whatever period this vessel may have sunk, there are
strong grounds for supposing that she was wrecked ; the loss
of mast, bowsprit, anchor, and cable, the wreck of the boat,
and the human bones found in and near her, are sufficient
proofs ; but what renders it still more convincing is a hole stove
through her bottom forward. And in the fire-place in the cabin
was found a conglomerated mass of cinders and charred wood,
which proves that the fire must have been extinguished sud-
denly, or the wood would have mouldered to ashes. Hence,
Sir, we may conclude that she was overwhelmed by some con-
vulsion of nature, from which circumstance, and the changes
that have taken place in the course of the river Rother, which
I shall presently show, we may yet arrive at the probable time
of her loss.

By various historians it appears, that at a very early period
the river Rother, which takes its rise in the parish of Rother-
fkld in Sussex, emptied itself at New Romney, the Lemanis
of the ancients. At the period of the Norman conquest it is-
sued to sea between Romney and Lydd, at a manor now call-
ed North Lade (a Saxon word for an opening to the sea,) and
the trench which constituted the body of the river from the
Rother at Appledore to the sea at North Lade, through Rom-
ney Marsh, by the sea dike called the Rhee Wall, is now dis-
tinctly to be traced. This bed of the river was granted by
Queen Elizabeth to the corporation of Romney, and by that
body it was lately sold for the redemption of the land-tax.

In the reign of Edward the First, about the year 1287, in
consequence of a dreadful storm, when the town of Winchel-
sea was destroyed by the rage of the sea, the mouth of the
Rother at Lydd was stopped, and the course of this river di-
verted into another and nearer track, by Appledore, into the
sea at Rye ; and by the flux and reflux of the sea, the old
channel became so swerved up that, about the time of Queen
Elizabeth,* it was scarcely navigable above Rye town for ves-

* " Yet now it (Rye) beginneth to complain that the sea abandoneth it
(such is the variable and interchangeable course of the elements,) and in
part imputeth it, that the river Rother is not contained in its channel, and
so loseth its force to carry away the seas and beach, which the sea doth
inbear into the haven." — Hayley's Manuscript Collections relating to Sussex,

64 Mr W. M. Rica's account of an ancient Vessel

sels of burden ; and liigher up, the river was so choked and
contracted, that the waters could not find sufficient passage in
it, and by documents in the possession of Mr Dawes of Rye,
one of the commissioners of the levels (to whom I am very
much indebted for civility, and for the assistance afforded me
in pursuing this inquiry,) I find that in 1623 a complete stop
to the navigation of the Appledore channel was made at Thor-
ney-wall, which is pointed out on the map which accompanies
this letter.

It appears, moreover, that that stop has never been removed
for the purposes of navigation, since lightermen were allowed
a tonnage for carrying goods over the stop; a sluice was
afterwards formed at Thorney-wall, simply for sewing the ad-
jacent lands. In May 1635 the navigation higher up the
Rother was very much impaired by a former breach made in
Spits-wall and Knolls-dam (which is some distance above Ma-
tham-Wharf,) being then as low as the bottom of the channel,
which made the waters of the upper levels forsake that part
of the Rother where the vessel has been found, turning them
through Wittersham-level. It was now feared there would be
no navigation at all between Appledore and Eodiam, and three
pens were in consequence put down in the cuts at Spit's-wall, so
that the waters might again be turned into their old tract, and
discharge themselves as before at the sluice at Appledore ; but
in October 1635 these pens were taken up, that the waters of
the Rother might have a free run into Wittersham-level ; and
in July 1636 the turning of the river through this level was
completely effected ; since which time there has been no navi-
gation between Knolls-dam and Matham-wharf, which limits
include the vessel, and the channel has been used only as a
sewer for the lands in East Matham-level. And it is further
stated, that at the commencement of the works connected with
the new channel, " the former navigation upon the Rother
was daily decaying ; so much so, that, had not the works in
Wittersham-level been undertaken and perfected, the naviga-
tion upon the Rother had before that time (July 1636) been

lost;'

To recover, however, a navigable stream from Thorney-
wall to Small-hythe, a dam was laid down at the latter place.

found under the old bed of the river Rather. 65

to keep up the waters between the two places ; but the navi-
gation never extended in any shape further then Thorney-wail,
since the sluice was laid there in 1623.

It is certain then that the vessel must have perished prior
to 1623.

And since it appears that for many years before, the Rother
had been decaying and gradually becoming, from the accu-
mulation of mud and silt, " scarcely navigable," or even deep
enough to sew the waters, it may be inferred, that, from the
great depth at which she lay buried in mud, or rather sea sand,
she must have been there very many years anterior to that pe-
riod, for had she not been below the bed of tlie river at that
time, she must have been discovered ; and it is not likely that
the commissioners would have allowed her to lie there to be
an obstruction to navigation and sewage, when, " previous to
1623, the sum of L. 20,000 had been expended in endeavour-
ing to drain the upper levels in and by the old course of Apul-
dore."

There is another material fact, which proves, that, at the
time the vessel foundered, the river at that place must have
been of considerable breadth ; for in addition to the vessel lying
under the bank, a log of oak, roughly hewn, 40 feet long, and
about 22 inches square, was found on the larboard side of the
vessel, one end of which rested on the gunwale, and the other
lay nearly at right angles to her length, upwards of ten feet
under the bank ; another log was also excavated by the side of
the former but above eight feet from the vessel ; these logs
must have unquestionably drifted and lodged against her.

Having thus far, I trust. Sir, established a limit, since which
the vessel could not have navigated, I shq,ll proceed to state a
few facts relative to the state of the river at a very early pe-
riod.

" In the 14th of Edward IV. A. D. 1475, certain commis-
sioners were appointed to view, report on, and repair the banks
of the Rother, which were much broken and decayed, by the
frequent incursions of the sea, and the violence of the tides.*"

And " a charter or letters-patent were granted, and directed
to certain knights and other person of quality in the 2d year

• Hayleys MSS. Collections relating to Sussex,
VOL. X. NO. I. JAN. 1829. B

66 Mr W. M. Rice"'s Account of an ancient Vessel

of Henry V. (1415) to repair the breaches past, and for pre-
venting the like for the time to come, between Rye and Bo-
diam Bridge ;*" and in the intermediate reigns between Edward
the First and this period, I find continual documents to the
same effect; particularly in the early part of Edward the Third's
reign, where, " by letters-patent granted, some new banks were
raised which thwarted this river, and prevented such vessels
and boats as used to pass on it with victuals, and other things
from divers places in Kent and Sussex to Ichingham, and were
likewise of the greatest prejudice to the market town of Sale-
hurst, which had been supported by the course of this water.
The king afterwards revoked these letters-patent, and com-
manded those banks to be demolished.""

It appears also, that " the tide at this time ebbed and flowed
above Newenden,'' (which is about two miles higher up the river
than the site of the vessel,) " and the stream was so strong,
that the bridge there was broken and demolished by it, and the
lands on each side the river were greatly overflowed, and much
damaged by the salt waters-""

In the reign of Edward the First an action was brought by
the Abbot of Robertsbridge. agajrvst the Lord of the Manor of
Knell, for inclosing salt marshes from the sea, whereby barges
and boats were hindered from bringing up provisions and mer-
chandise, to the market of Robertsbridge.

I have taken much pains in searching those authors who have
given the best information respecting the changes which have
taken place on the coast of Sussex and the neighbouring coast
of Kent, in order to get together the aera of the most remark-
able floods and tempests which have happened within these
parts within the last five or six hundred years.

Hayley, in his collections for Sussex, states that " in the 12th
of Elizabeth chanced a terrible tempest of wind and rain, both
by sea and land ; the waters came in so vehemently at Rye,
that they brake into the marshes and made such way that, where
of late years and now before this great flood came, a cocJcboat
could not pass in at low water, now a Jisherman drawing six
feet water and more may come in.""

This shows the state of the mouth of the haven at that period;
and as I have given clear proofs that the river was decaying

Jbund under the old bed of the river Rother. 67

and contracted higher up at a very early period, and also shown
that at the period when the vessel foundered, it must have been
of considerable breadth at Math am- wharf, which is ten miles
from the sea, I think this tempest YSiXhevJixvours^ than makes >
against the speculation for her antiquity.

Many other general tempests and storms have been record*
ed by various writers, but we read of none that have particu-
larly affected this part of the country until the period before
cited, when, by a great convulsion of nature, Winchelsea was
swallowed up by the sea, and the whole face of the country
changed. This storm is mentioned by all the historians of
Kent. Stowe in his Chronicles thus states it: " In 1287, on
new-year's-day at night, as well through the vehemency of the
wind as violence of the sea, divers places in England adjoin-
ing the sea were flooded, so that an intolerable multitude of
men, women, and children were overwhelmed with the waters ;"
and Somner in his " Treatise on the Roman Ports and Forts^"*
says " About 1287, the sea raging with the violence of winds
overflowed and drowned Promhill (near Lydd, a town at that
time well frequented,^ the lands wherethe town stood are now call-
ed Broomhill), and made the Rother forsake its channel, which
before emptied itself into the sea at Romney, and stopped its
mouth, opening a new and nearer way to pass into the sea by
" Rhie,**' now called Rye ; and afterwards fell into the Apple-
dore waters, wheeling about, and running into that arm of the
sea or estuary insinuating into the lands by Rye.'' By Jeaks's
Charters also we learn, that Winchelsea was drowned in the 16th
of Edward the First.

I have now arrived at a period beyond which, speculation
becoming more and more doubtful, I am backward in hazard-
ing an opinion ; and since history does not furnish us with the
aera of any violent or destructive storm on this coast, for very
many years prior or subsequent to the one above-mentioned, I
shall conclude this letter, leaving it for others to determine,
from the facts here stated, as to the probability of the vessel
having perished in or before that great tempest, or at a period
between that and the storm which took place in the reign of
Queen Elizabeth.

68 Mr Tregaskis on the Expansion of Vapour.

AiiT. X. — On the Expansion of Vapour, By Richard
Tregaskis, Esq. of Perran, near Truro. Communicated
by the Author.

XliXPERiMENTs on the elastic force of vapour in contact with
water at high temperatures are attended with difficulty, con-
siderable expence, and some danger. Hence few experiments
have been made on steam beyond the temperature of 343° of
Fahrenheit under a column of mercury. Even at this tem-
perature steam supports a column of mercury 20 feet in
height.

The great difficulty attending experiments above this height
(which is equal to eight atmospheres) renders it particularly
desirable that some correct method be given for the calcula-
tion of force by temperature, founded on accurate experiments
made below it.

Temperature and force increase, it is believed, in some
geometrical progression, but their ratios respectively have not
been published ; — perhaps they are not known. If they in-
creased in the same ratio, — if double the sensible heat would
generate exactly double the force, — there would be no difficulty
in calculation. But as the increase of force and temperature
are very different, a different ratio is required for each factor,
and the corresponding terms in each series should point out
the relative temperature and force.

In order to this, some known fixed point is necessary for the
commencement of the scale. But zero of vapour, like that of
temperature, has not been fixed. The freezing point of water,
or rather the melting point of ice, naturally presents itself as
the zero of vapour ; but it has been placed lower on high
authority. Yet if the vapour of water has no existence till
fluidity is produced, it follows that the commencement of
fluidity is low enough ; for ice must be liquefied before it can
be vaporized.

With this in view, I have examined various experimental
results on the elasticity of vapour, and compared the column of
mercury supported with the temperature required to maintain
vapour of sufficient tension to support the column. The result

Mr Tregaskis o?t the Ka^pansion of Vapour. 69

of this comparison is, that one-fifth added to any given por-
tion of heat already communicated to water, as indicated by the
thermometer ^rom the freezing point., will double the elastic force
of its vapour. The annexed table is calculated on this principle,
and the calculation agrees well with experiment from 3Q° be-
low the boiling point up to 343° of Fahrenheit, the highest ex-
periment hitherto pubhshed. This law is easily reducible to
a geometrical ratio for each factor. The ratio of force being 2,
we have only to reduce 14 to the decimal 1.2 for the ratio o
temperature. Having found the ratio, it is easy to calculate
the force of vapour at any given temperature, and vice versa,
(provided the same ratio answers, while vapour retains the
same physical condition, (which I think will not be questioned,)
viz. from the freezing point upward till vapour is changed into
permanent gas.) For, by counting the number of terms in
each series produced by the continual multiplication of both
factors by their respective ratios, the corresponding tempera-
ture and force is seen at once. For example, —

1st. 2d. 3cl. 4th.

Temp. 180 x l.^:=z91Q X 1.2 = 259.2 X 1.2 = 311.04.

Force, 30 X 2 = 60 x 2=120 x2 =240.
And by adding 32 to either of the terms in the series of tem-
perature, we have the degree of Fahrenheit. For instance, at
the fourth term we have for temperature 311*^.04, force 240.
311°.04 -I- 32° = 343°.04, so that the force of vapour by calcu-
lation at 343°.04 of Fah. supports 240 inches of mercury, and
at 343°.6 of Fah. it supports 240 inches by Mr Southern's ex-
periment.

From this it appears that the calculation answers Mr S.'s
experiment to the fraction of one degree on 343°. The fourth
line in the annexed table is nearly a mean between the expe-
riments of Ure and Southern. The third agrees with that of
Dr Ure to a small fraction. The next term under the boiling
point agrees to the fraction of an inch with Mr Dalton. And
M. Betancourt's statement, that vapour at 182° has half the
tension at 212°, agrees with the table exactly.

It will be observed that the experiments I have selected are
in that part of the thermometric range which is most satisfac-
tory, viz. from 182° upwards. In experiments near the freez-

TO Mr Tregaskis on the Expansion of Vapour.

ing point, where one degree does not produce an increase of
force equal to the 1-1 40th part of an inch, the result must be
almost inappreciable. It may not be unworthy of remark, that
there are only twelve terms in the series from the bottom of the
table up to the temperature which Dr Murray states to be
equal to red-hot iron, fully visible in daylight, — a temperature
which will change vapour into permanent gas; so that this
table, which reaches the utmost limit of vapour, has only 12
terms, 5 of which (almost half the table) have been proved by
experiment.

Table of the Elastic Force of Vapour.

Additional
Distance from the ^ ^§5^^^ J^^" Degrees on Inches of Atmospheres.

zing point.

double the
Force of

ranrenueu s
Scale.

ivicruury.

Vapour.

150^

30°

182°

1
5

180

212

216

248

259.2

291.2

120

311.04

62 '

343.04

240

373.248

405.^48

480

447.897

479.897

960

537.477

107

569.477

1920

644.972

129

676.972

3840

128

773.967

155

805.967

7680

256

928.760

186

960.760

15360

512

1114.512

1146.512

30720

1024

Mr Tregaskis on the Expansion of Vapour. 71

Comparison with

Experiment.

Dalton,
In this all agree.

Temp. Force.

182° =: 15.86 inches of mercury

Ure,
f Ure,
( Southern,

Southern,

248.5== 60.40,
290 = 120.15.
293 = 120.
343.6 = 240

One practical advantage to be derived from the calculation
of force by temperature is the application of a thermometer
as a check on the safety valves of steam-engines. Many per-
sons, not naturally timid, are unwilling to venture on board a
steam-vessel through fear of its blowing up.

A naval officer, distinguished for bravery, told me not long
since that he would never trust his life in the hands of a care-
less fellow, who, by throwing a pocket-handkerchief on the
lever of a safety-valve, might blow Up the vessel. Prejudice
of this kind might be removed and real danger prevented, by
means of a small steam-pipe carried from the boiler to a ther-
mometer properly graduated in the cabin. The force of steam
in the boiler would then be apparent to the passengers, and
the most timid be released from apprehension of danger. A
table for that purpose is easily calculated.

73 Mr Tregaskis 07i the Expansion of Vapour.

Art. hi. '^Theorem for computing the Elastic Force of Fa-
pour. By Richard Teegaskis, Esq. in a Letter to the
Editor. (See Article X. in this Number.)

Sir, Perran, near Truro, 6th Nov. 1828.

The table in my paper on the expansion of vapour having
only twelve terms, requires considerable extension to render it of
practical utility. I have therefore to request the insertion of
a method for the calculation of a more extended table.

The President of the Royal Society, who is always ready to
assist and encourage any attempt at further discoveries in
science, however humble, was requested, on his annual visit to
Cornwall, to look at the paper in question. He was pleased
with its simplicity, and, assuming my statement to be the law
of expansion, kindly presented me with the following theorem,
by which a table may be easily calculated to any subdivision
of parts ; or (on the assumed law) the force of vapour may
be found by it without a table at any distance above or below
the boiling point of water. — I am. Sir, very respectfully, your
humble servant,

RiCHD. Tregaskis.

To Dr Brewster.

THEOREM.

Let a = the number of degrees of Fahrenheit above or below
the boiling point.

180 + a

Then — =: t the temperature.

180

Let E = the elasticity, that of steam at the boiling point being
unity.

Loff. 2
Then Log. E = ^^^^^ ^^ X Log. /. = 3.802 X Log. t.

Loff. 1.2
Log. t = L^|— ^ X L°g- ^ = 0.263 X Log. E.

a = 180 X < — 180= 180 xnat.no. of (^~~X Log.jE;^ — 180
= 180 X nat.no. of (3.802 X Log. £.) —180.

Dr Heineken's Meteorological Journal hept at Funchal 73

Art. ym,'^ Abstract of a Meteorological Journal kept at
Funchal, in the island of Madeira, from January \st to
December Slst, 1827.* By C. Heineken, M. D. Com-
municated by the Author.

The barometer is one of Newman'*s mountain instruments,
with an iron cistern into which its thermometer plunges. It
hangs within doors at a window with a south aspect, fifteen
feet from the ground, and eighty-nine above the level of the
sea. The Hygrometer is DaniePs, used at the same win-
dow, but kept in a dry cupboard within the room. The maooi-
mum thermometer is one of Newman's horizontal instruments.
It hangs in an open passage which runs through the house,
and has a room over it, is removed from all artificial draught,
ai?d quite uninfluenced by the sun either directly or by reflec-
tion. The minimum one is by Dollond. It hangs against a
wall with a north aspect, and is sheltered from rain. They
are both at the same height as the barometer. The sun ob-
servations are made on a black bulb horizontal thermometer
by Newman, three feet from the earth, and 280 above the level
of the sea. Rain-gage No. 1. is on the roof of a house,
twenty-five feet from the ground, and ninety-nine above the
sea. No. 2. is in the same situation as the sun thermometer,
and on the ground.

1827.
January.
Pressure. (Inches.) Corrected for temp. Temperature.
Max. 30.480 61° = 30.400 Max. 66°
Min. 29.790 62 = 29.718 Min. 51
Mean 30.203 64 = 30.118 Mean 58.9

Diurnal range, max. 12® ; min. 5° ; mean 9*.

Rain, 2.86 in. No. 1 ; Dew Point, max. 64 ; min. 46 ; Dry-
ness, max. 21, min.

IFintZ^, N. 3 ; N. E. 10 ; E.2; S. E. 6; S. 2 ; W. 6 ;
N.W. 2;=31.

• Two observations (10 a. m. and 10 p. m.) are made on the barometer,
and one (10 a. m.) on the hygrometer daihj'

74 Dr Heineken's Meteorological Journal kept at FunchaL

A fine winter month, with a remarkable prevalence of east
winds. No snow has yet fallen on the mountains, and the
liorth-west winds have been unusually raw. — N.B, In speak-
ing of snow, it is always implied, within view from the town,
and about 5000 feet above the sea.

February:.

Pressure. (Inches.) Cor. for temp. Temperature.

Max. 30.250 67 =30.159 Max. 69

Min. 29.750 60.5 =29.678 Min. 50

Mean, 30.045 62.3 = 29-967 Mean, 58.5

Diurnal range, max. 14 ; min. 5 ; mean, 10.

Rain^ 2.62 in. No. 1 ; Dew Pointy max. Q5.B5y min. 49 ;
Dryness^ max. 1 4 ; min. 0.5.

WindSy'^.Q', N.E. 4; E. 2; S.E. 1; W.13; N.W. 2;
= 28.

A cold winterly month, excepting the last week. Barome-
ter more variable than I ever remember to have observed it.

March.
Pressure. (Inches.) Cor. for temp. Temperature.

Max. 30.400 67 =30.314 Max. 69-5

Min. 30.040 m = 29-955 Min. 53

Mean, 30.224 66 = 30.139 Mean, 60.9

Diurnal range, max. 13; min. 8; mean, 11.
Rain, none ; Dew Point, max. 63, min. 50 ; Dryness, max.
15, min. 3.

Trmd*,N.4; N.E. 11; E.6; S.E.3; W.3; N.W.4;

= 31.

A remarkably fine month, more like June than March. Ba-
rometer rery steady and unusually high.

April.

Pressure. (Inches.) Cor. for temp. Temperature.

Max. 30.210 69=30.112 Max. 69

Min. 29.6J0 67=29521 Min. 54

Mean, 29994 67 = 29903 Mean, 62.2

Dr Heineken's Meteorological Journal kept at Funchal. 75

Diurnal range, max. 13; min. 5; mean, 10.
Rain, 2.19 in. mean ; Dew Pointy max. 67, min. 51 ; Dry-
ness, max. 15, min. 1.

Winds, N. 3; N. E. 8 ; E. 4; S. 1; S. ;W. 2; W. 11 ;

N.W. 1;=30.

A fine warm month.

Pressure.

Inches.
Max. 30.310
Min. 30.020
Mean, 30.189

May.

Cor. for temp.

69 = S0.212
69 = 29.922
69 = 30.089

Temperature.

Shade. Sun.
Max. 73 108
Min. 57 79
Mean, 65,^ 96.3

Diurnal range, max. 14; min. 6; mean, 11.

Rain, none ; Dew Faint, max. 69, min. 51 ; Dryness, max.
16; min. %

Winds, N. 1 ; N. E. 19 ; E. 1 ; W. 6; N. W. 4;=31.

A remarkably fine month. So forward and warm a spring
has seldom been remembered.

sA :

June.

-' .r?

Pressure.

Cor. for temp.

Temperature.

Inches.

Shade. Sun.

Max. 30.280

74 =30.166

Max. 77.5 109

Min. 29.970

74 =29.859

Min. 50. 83

Mean, 30.101

72 =29.998

Mean, 68.4 97.9

X' ^t

Diurnal range, max. 14; min. 8 ; mean, 11.
Rain, 0.16 in. mean ; Dew Point ; max. 73, min. 61 ; Dry-
ness, max. 12; min. 1.

Wi7ids, N. 1 ; N.E. 14; E. 4; W. 8; N.W. 3 =30.
A warm fine summer month.

July.

Pressure.

Cor. for teinp.

Temperature.

Inches.

Shade. Sun.

Max. 30.270

77 =30.153

Max. 84 116

Min. 30.020

76 =29.906

Min. 62 96

Mean, 30.175

76 =30.061

Mean, 71.6 102

76 Dr Heineken'*s Meteorological Journal Icept at Funchal.

Diurnal range, max. 16; min. 10 ; mean 14.
Raiiiy none ; Dew Pointy max. 76 ; min. 57 ; Dryness^ max.
16 ; min. I.

Winds, N. 1 ; N.E. 25; E. 3; W. 1 ; N. W. 1 = 31.
A remarkably fine and very hot month.

August.

Pressure. Cor. for temp. Temperature.

Inches. Shade. Sun*

Max. 30.210 77 =30.093 Max. 83 111

Min. 29,990 78 =29.871 Min. 62 96

Mean, 30.109 77,4 =29-992 Mean, 72.3 103.8

Diurnal range, max. 17; min. 12; mean, 15.
Rain, none ; De7v Point, max. 77, min. 48 ; Dryness, max.
36, min. 2.

Winds, N. E. 27 ; E. 2 ; S. E. 2 = 31-
A fine clear month.

September.

Pressure. Cor. for temp. Temperature.

Inches. Shade. Sun.

Max. 30.310 74 =30.196 Max. 80 110

Min. 30.030 73 :=. 29.924 Min. 60 93

Mean, 30.147 75 = 30.036 Mean, 70.9 102

Diurnal range, max. 17 ; min. 12 ; mean^ 14.
Rain, 0.15 in. mean ; Dew Point, max. 74; min. 57 ; Dry*
ness, max. 17; min. 2.

Wi7ids, N. 3 ; N. E. 14 ; E. 3 ; W. 10 = 30.
A fine seasonable month.

October*

Pressure. Cor. for temp. Temperature.

Inches. Shade. Sun.

Max. 30.270 75 =30.159 Max. 77 105

Min. 29.720 70 -29-622 Min. 55 73

Mean, 30.063 72 = 29-958 Mean, 67-2 95.4

Diurnal range, max. 18; min. 11 ; mean, 15.
Rain, 3.24 in. mean ; Dew Point, max. 74, min. 55 ; Dry--
ness, max. 17, min. 1.

Dr Heineken's Meteorological Journal kept at Funchal. 77

Winds, N. E. 16; E. 2 ; S. W. 4; W. 4; N. W. 5 = 31.

A fine autumnal month, with a moderate fall of rain. The
summer has been the dryest and finest long remembered ; for
months scarcely a cloud was seen.

Pressure.

Inches.
Max. 30.460
Min. 29.400
Mean, 30.007

November.
Cor. for temp.

m =30.371
66 =29.314
68 =29.984

Temperature.

Shade. Sun.

Max. 73 101

Min. 51 73

Mean, 62 92.1

Diurnal range, max. 19 ; min. 11 ; mean, 16.

Rain, 6.95 in. mean ; Dew Point, max. 68 ; min. 65 ; Dry-
ness, max. 13 ; min. 2.

Winds, N. E. 17 ; E. 5; S. E. 1 ; S W. 1 ; W. 5 ; N. W.
1 = 30.

Rather cold, but seasonable ; much mo7'e rain from the east-
ward than is at all usual.

Pressure.

Inches.
Max. 30.440
Min. 30.180

December.
Cor. for temp.

65 =.30.354

66 =30.095

Temperature.
Shade. Sun.
Max. 73 103
Min. 50 80

Mean, 30.313 66.9=30.215 Mean, 69.2 92.1

Diurnal range, max. 21 ; min. 9 ; mean, 15.
Rain, none ; Dew Point, max. 66 ; min. 50 ; Dryness, max.
18 ; min. 3.

Winds, N. 4 ; N. E. 19 ; E. 5 ; S. E. 1 ; W. 2 = 31.
A remarkably dry warm month*

Pressure.

Inches.
Max. 30.480
Min. 29.400
Mean, 30.130

Annual Results.
Cor. for temp.

61 =30.406
66 =29.314
70 = 30.032

(1827.)

Temperature.
Shade. Sun.
Max. 84 116
Min. 50 73
Mean, 65.6 97.6

\
7B Dr Heineken's Meteorological Journal kept at Funchal.

The observations iu the sun were made only for eight
months, from May to December inclusive.

Rain, 18.17 in. ; Dew Point, max. 77 ; min. 48 ; Dryness,
max. 21 ; min. 0.5.

Winds, N. 26 ; N. E. 184 ; E. 39 ; S. E. 14 ; S. 3 ; S. W.
7 ; W. 69 ; N. W. 23 = 365.

1826 and 1827.

Two years.

Pressure. Cor. for temp. Temperature

Max. 30.590 =: 30.505 Max. 84

Min. 29.390 == 29.294 Min. 50

Mean, 30.131 = 30.031 Mean, 64.9

Rain, 25.03 in. mean ; Dew Point, max. 77 ; min.. 40 ; 2>?*y-
neasy max. 30; min. 0.

Winds, N. 47 ; N. E. 341 ; E. 95 ; S. E. 34 ; S. 5 ; S. W.
14 ; W. 143 ; N. W. 52 = 733,

Rain for Three Years, 1825 to 1827.

Viz. 1825, 20.43 in. 1826, 43.35 in. 1827, 18.17 in.
Mean, 27.32.

Pressure and Temperature for the same Three Years.

Pressure, Max. 30.62 ; min. 29-39 ; range, 1.23 in.
Temperature, Max. 84 ; min. 50 ; range, 34°.

In the year 1824 I commenced keeping a meteorological
journal, which, in consequence of ill health, occasional resi-
dence in the country, and other circumstances, was not pur-
sued with sufficient energy and regularity to warrant its pub-
lication before 1826. At first I attempted three observations
during the four-and-twenty hours ; viz. at sunrise, 2 p. m.,
and sunset ; but I soon found that, do what I would, the in-
struments remaining stationary were inevitably influenced hy
the sun, either immediately or by reflection. In an open turret,
simply tiled as ours are, the effect was the same ; and during
at least eight months in the year, the sun was so vertical that
perfect shade in the same spot could not be maintained through-

Dr Heineken's Meteorological Journal kept at Funchal 79

out the day. As, therefore, there appeared to be but two re-
sources against this inconvenience, viz. several instruments in
different situations and noted at different times, or a register
thermometer within doors, and having a room over it, I chose
the latter, and in the Philosophical Magazine for November
and December 1827 gave the results. These have been in a
very fair and candid manner objected to in this Journal, (Ed,
Jour, of Science, No. xvii. p. 171,) and I am glad of the op-
portunity which it affords of repeating why I deviated from the
usual mode of taking the maximum observations, and of my
doubt whether any taken out of doors with a single and sta-
tionary instrument can be strictly correct for shade maxima,
in a latitude where the sun is so vertical. Upon this the whole
question appears to me to hinge. If observations made in as
perfect, or rather imperfect, shade as a stationary instrument
can insure, be admitted as correct, then the mode which I
adopted is certainly a bad one, and its deductions false; but if
such as are made upon several instruments are alone to be
trusted to, it is I think the lesser of two evils; and, was there
not the weight of such authority against me, I should almost
be bold enough to prefer the mean which thence resulted to
that obtained by the other mode. Dr Brewster''s Formula I
own staggers me more than the other authorities, because they
were not from observations made upon the spot for any length
of time. In the quotation of Humboldt's there must, I think,
be some mistake. It is stated to be 7^.22 ; but in the transla-
tion (I have not the original) of his " Personal Narrative,^'' it
is given by him, on the authority of Cavendish, 68.9 ; and
Santa Cruz, on the south side of Teneriffe, four or five degrees
more south than Funchal, and wo^oriow^Z// hotter, he gives o/i/y
71.10.* Kirwan makes the mean of Funchal 68.9, — and I
in 1824 made it 68.2, and in 1825, 68.6,— by an out-of-door
stationary instrument. It appears then, I think, satisfactorily,
that the dissonance of result is entirely to be attributed to the
different mode of making the observations, and not " to some
error either in the instruments or in the observations." In a
higher latitude an instrument within doors would, as it is ob-
served, " give a higher temperature than if it had been placed

M. Von Buch is quoted in tbesame PijbUciUkMi as making it ?U.

80 Dr Heineken's Meteorological Journal kept at Funchal.

in the open air ;"" but here the result would be, and actually is,
diametrically opposite. Should health and other concomitants
permit, I shall endeavour next year to obtain maxima from se-
veral instruments, and in the meantime, should feel obliged
by any hint as to the readiest and most correct mode of making
maxima observations on temperature in such a latitude as
this. C. He I NEK EN, M. D.

Funchal, Madeira^ ^5ih October 1825.

Q3SERVATI0NS BY THE EDITOR.

The very judicious and candid method which Dr Heineken
has taken to remove the doubts which we expressed in a for-
mer Number, (No. xvii. p. 171,) respecting the accuracy of
his measure of the mean temperature of Funchal, has satisfied
us of the correctness both of his instruments and his observa-
tions. We committed a mistake in asserting that Humboldt
made the mean temperature 72°. 22, for it is only 68°.5 in his
Treatise on Isothermal Lines ; but it was still a matter of sur-
prise to us, that the mean temperature should be so low as
64!°.3, when Humboldt gave 64°.04 for the mean temperature
of the coldest month. It will be generally found that the mean
temperatures of all warm climates are given too high, not only
from the difficulty of protecting the external thermometer from
the indirect influence of the sun, but also from the want of a
sufficient number of evening and morning observations. Hence
we are disposed to think that the temperature of 68°.5, as given
by Humboldt, would require to be diminished from both these
causes.

The following are the different measures which have been
given of the mean temperature of Funchal.

Humboldt,

68°.5

Kirwan,

68.9

Dr Heineken in 1824,

68.2

Do.

1825,

68.6

Do.

1826,

64.3

Do.

1827,
Mean,

Q5.Q

67°.35

Dr Brewster's Formula,

68 .(^5

Mr Williams's account of two Thunder Storms. 81

We would beg to request Dr Heineken to observe the ther-
mometer at 10'^ A. M, and 10 p. m., as it would be interesting
to compare the annual temperature thence deduced with that
which is obtained from the maximum and minimum thermo-
meter. It would be very desirable also to have a few obser-
vations every month on the temperature of springs or deep
wells.

The situation of Funchal, near the place where the isother-
mal lines of the Old World begin to bend towards the equa-
tor, and to mark the influence of the cold pole of America,
renders the accurate determination of its mean temperature a
matter of great importance to meteorology.

Art. XIII. — Account of Two Thunder Storms which hap-
pened in Worcestershire^ in which it appeared the Electric
cat Discharge passed from the Earth towards the Clouds.
By John Williams, Esq. Communicated by the Author.

Atorcesteii and its neighbourhood were visited by a thunder
storm on the evening of the 14th of December 1825. The
barometer throughout the day stood at 29.25, and the thermo-
meter at 8 A. M. was 44', and at 2 p. m. 50°. The lower wind
was brisk from the S. S. W., with a damp mild feel, indicating
the presence of much aqueous vapour. Clouds were seen mov-
ing in three distinct currents. The uppermost current came
from the west, a middle current from the S. W., and the lowest,
in which the clouds appeared to move more rapidly, came from
the south, and there were openings of clear sky of a deep blue
colour. From 7 till 8 o'clock p. m. lightning was seen flashing
at intervals in the S. W., W., and N. W., proceeding appa-
rently from light clouds. At half-past 8 the sky became very
dark in the N. W., the flashes of lightning more vivid and
frequent, and it began to thunder. A storm of very unusual
violence for the season of the year immediately followed, at-
tended with wind, rain, and hail. The explosions of thunder
were almost incessant for about an hour ; and the intensely
vivid glare of the lightning, alternating with extreme darkness,
produced a most awful eflect.

VOL. X. NO. I. JAN. 1829. F

82 Mr Williams's account of Two Thunder Storms

The instantaneous sound of the thunder following the flash
of lightning, and the after long-continued roll in the distant
parts of the cloud, made me conclude the latter was negatively
electrified, and that the electricity passed from the surface of
the earth to the cloud. And hearing the following morning
that the west side of the lofty beautiful spire of St Andrew's
Church in Worcester had been struck by the lightning, I re-
quested a friend to accompany me to the church-yard to examine
the mark where the surface of the stone was injured. The mark
was and still is distinctly visible about halfway between the top of
the tower and the weathercock, which terminates the spire ; the
smooth surface of the stone being torn off about an inch in depth,
i9fo or three inches in width, and about two feet in length, pre-
senting the following appearance and inclination from a perpendi-
cular. See Plate I. Fig. 3. Before entering the church-yard,
I remarked to my companion that I expected to find all the frag-
ments of stone on the ground on the west side the church, fac-
ing the direction of the storm, as I imagined the electrical dis-
charge passed up the surface of the wet stone, till it came to the
point where we observed the mark, and from thence through
the air in a diagonal direction to the cloud. The fact turn-
ed out as I predicted ; the fragments of stone were all found
scattered on the ground, about thirty feet from the west side
of the tower. None could be met with in any other part of
the church-yard; and that these fragments (which are still
in my possession) were the identical pieces of stone torn by
the electrical discharge from the surface of the spire, I could
have no doubt, for the stone exactly corresponded in texture
with it ; the smooth wrought side being of the colour of the
general surface of the spire, and the rough fractured portion
of each piece presented the appearance of the same stone when
recently broken. A gentleman who witnessed the storm from
the quay on the opposite side of the Severn, about six hun-
dred yards from the west side of the church, saw the flash,
which he described as resembling an intensely bright light,
which seemed to come from the spire, and pass over his head
towards the dark cloud in the west, attended by a sudden
and most tremendous crack, and accompanied by a loud rustling
sound, like a high wind passing through the rigging of the

in which the Electricity passed from the Earth. 83

barges in the river. The sound gradually terminated in a heavy
distant roll of thunder in the clouds westward of him.

Accomit of a Thunder Storm at Malvern, Worcestershire.

The morning of the 1st of July 182()5 being warm and sun*
ny, the barometer at 8 a. m. 30.27, the thermometer at the
same hour being at 72°, and at half-past 2 p. m. 82°, very
heavy dense cumuli began to form soon after 10 a.m., and at
2 p. M. it thundered loud in the S. W. and in the W. N. W.
At a quarter before 3 p. m. a very loud clap of thunder was
heard in the village of Great Malvern, about seven miles S. W.
of Worcester. A party, consisting of two sons and four daugh-
ters of Mr Hill of Dymock, Gloucestershire, and Miss Wood-
gate of Hereford, accompanied by two servants, were upon
the hills above the village, and, observing a storm gathering
round them, with heavy thunder, they retired to take some
refreshment they had brought with them, to a hut situa-
ted on a high ridge about three or four hundred yards below
the summit of the mountain. Several huts had been erected
on the hill by the Countess of Harcourt for the accommodation
of the company frequenting Malvern, and for the purpose of
affording shelter in case of a sudden shower. These huts were
small circular buildings, built with the rough fragments of gra-
nite found on the surface of the hills, the outside walls beins:
white-washed with lime ; and the roofs were made of sheet iron.
It is not a little remarkable that Miss Elizabeth Hill observed
when she entered the hut, that she felt alarmed lest the iron
roof should attract the lightning. They had scarcely entered
this retreat, and were about to take their refreshment, when a
violent storm of thunder and lightning came on from the west,
and at a quarter before three p. m. one of the Mr Hills, who
stood at the entrance which fronted the east, saw a ball of fire
which seemed to him moving on the surface of the ground. It
instantaneously entered the hut, forcing him several paces for-
wards from the doorway. As soon as he recovered from the
shock, he found his sisters on the floor of the hut, fainting, as
he supposed, from alarm. He instantly sent oif one of the par-
ty who had escaped injury for assistance, and the usual means
of recovery were applied by a medical practitioner from the

84) Mr Williams's account of two 'thunder Storms

village. Miss Elizabeth Hill and Miss Woodgatc appeared to
have died instantly, and Miss Margaret Hill and the rest of
the party were much injured. The explosion which followed
the flash of lightning was terrific, and alarmed the inhabitants
of the village below. Soon after I heard of the accident, I
went and examined the hut. I found a large crack on the
west side the building, which passed upwards from near the
ground to the frame of a small window, above which the iron
roof was a little indented. The fragments of stone, when first
observed, were all found on the west side the hut, and these
were readily distinguished from other loose stones, owing to the
lime-wash which coated the exterior surface. I found a few of
the larger pieces of stone on the east side also ; but I was in-
formed many curious persons had visited the spot before me ;
and, after examining and fitting these fragments to the part of
the building from whence they had been torn, threw them ca-
sually about the hut.

The following is an account of another storm attended with
thunder and lightning.

" In the night between the 30th of November and the 1st of
December 1821 there was a violent gale of wind from the S.W.
A mast of a sloop, lying in the river at Newport in Monmouth-
shire, was struck by the lightning about twelve feet above the
deck and shivered to pieces, and all the splinters were driven to
windward.^'

In these three instances the thunder clouds appear to have
been in a negative state of electricity, for, had the stroke of light-
ning passed from the clouds downwards, the fragments of stone
and splinters of wood would have been scattered in a direction
opposite to the storm ; and, from the observations I have made
during the last twenty years, I am inclined to think, when ob-
jects are struck by lightning, the passing cloud is often nega-
tively electrified. When a thunder storm is approaching or is
gone past in the day-time, the direction of each stroke may of-
ten be seen if not too near the observer, say at a distance of
from two to about five miles ; but when it takes place in the
night, or very near the place of observation, the sudden great
glare of light prevents our seeing the direction of the stroke. In
the day-time, at the distance aforesaid, I have often been able
most distinctly to trace the direction of the electrical ball ; and

in which the Electricity passed from the Earth. 85

it has frequently appeared to irie like the motion of a sky-rocket
rising with extraordinary rapidity, commonly inclined when
first rising from the earth, and becoming more horizontal when,
it reaches the cloud, where it often divides into two ; sometimes
it describes a curved line with zig-zags. The thunder seems to
proceed first from the quarter where the ball of fire appears to
have risen, and terminates in a distant roll amongst the clouds.
The cause of the negative state of clouds may perhaps be ex-
plained in the following manner : — The capacity of water for
electricity is increased when it assumes the state of vesicular
vapour, as may be shown by the experiment of throwing water
on hot coals. The rising vapour immediately takes the shape
of that kind of cloud denominated the cumulus, and is positively
electrified, as may be proved by the electroscope. But in the
slower process of natural evaporation by the sun and wind, the
intensity of the electricity of the rising vapour is not sufficient
to be shown in the same way. However, there is reason to think
the fact is otherwise ; and Dr Franklin*'s ingenious experiment
of the electrified can and chain throws considerable light on
the subject. In this experiment, by raising the chain from
the can, the connecting electrometer proves that the capaci-
ty of the chain for electricity is increased by its increase
of surface exposed to the air, as the electrometer indicates
a weak intensity. But on again returning the chain into
the can, the original intensity is manifested. So each particle
of rising vapour as it leaves the earth's surface, combines with
caloric, and partakes of the electricity of the common reservoir,
the earth. It remains in mixture with the air, but in a state of
very minute division ; for we observe, whether raised by the sun's
heat from moist soil, or from water artificially heated, the parti-
cles of vapour or steam disappear, and do not disturb the tran-
sparency of dry air, till they rise into a stratum of air, where
the cold occasions it to be again condensed into vesicular va-
pour or clouds. This, in an ordinary summer's day, takes place
at different heights in the atmosphere, according to the heat
and dryness. It is probably the dew point of that stratum of air
where the fleecy clouds begin to form in a clear sunny morning ;
and, as compared with the known height of mountains, these
clouds are first seen at from 1500 to 3000 feet. These small
fleecy clouds sometimes rc-evaporatc soon after they begin to

86 Mr Haidingcr on the Parasitic Formation of Minerals,

form, especially in settled serene weather, attended by a high
barometer, and the air in a positive state of electricity. On
the contrary, if these clouds increase in size, the upper surface
takes the shape of the cumulus, which swells very rapidly in
size, becoming very dense, and of a most brilliant white colour
on the side exposed to the sun. All the smaller neighbouring
clouds are attracted by the larger. But the increase of capa-
city for electricity, which keeps pace with the increase of va-
porous surfaces exposed to air, cannot receive a supply from
the earth, and but very slowly from the air. At length its rela-
tive state of electricity, as compared with^the earth's surface, is
of sufficient intensity to overcome the resistance of the plate of
air between the earth and cloud, and the discharges of electric
matter pass upwards. This opinion is offered as the result of
many years observation, and as an humble attempt to explain
one of the causes which produce negatively electrified clouds,
and those local thunder storms which sometimes prevail for se-
veral weeks together in the summer months.

Art. XIV. — On the Parasitic Formation of Mineral Species,
depending upon Gradual Changes which taJ^e place in the
Interior of Minerals, while their External Form remains the
same. By William Haidinger, Esa. F. R. S. Edin.—
( Concluded fro7n last Number, p. 9Q%)

IX. Changes in some of the Earthy Minerals and others.

The explanation of many of the cases enumerated above, de-
pends upon the ordinary laws, active in our chemical laborato-
ries. Carbonates are changed into sulphates, metallic sub-
stances are oxidized, copper is replaced by iron : in general
weaker affinities give way to stronger ones. The conversion
of sulphates into carbonates, and other cases, may perhaps de-
pend upon some process of mutual decomposition, in which
one of the products has been subsequently removed ; but the
specimens preserved in collections do not usually present any
explanation of the facts which they furnish. We must en-
deavour to ascertain the causes which have contributed towards

depending on their Internal Changes. 87

successive alterations in the chemical composition of minerals,
by observing their jiatural repositories, veins and beds, and
mountain masses, exposed to the action of the atmosphere,
and of water, and to the mutual reaction of the mineral spe-
cies of which they are constituted.

One of these examples, where the cause of a change in ap-
pearance is not so palpable, is the well-known one of the sub-
• stance usually named the Gray Andalusite. Its specific gra-
vity alone being above 3.5, while that of the real andalusite
never exceeds 3.2, would be sufficient to prove them to belong
to different species. But Prof. Mohs has found the gray crys*
tals actually to consist of a great number of small individuals
of disthene, with an easy cleavage, whenever they are large
enough to be distinguished from others, and Ijing in different
directions throughout the mass. Both minerals are found in
nodules of quartz engaged in mica-slate. From the analysis
by Arfvedson, it appears that disthene is a compound of one
atom of silica and two of alumina, or AP Si. Andalusite con-
tains about 83 per cent, of the same mixture, the rest being a tri-
silicate of potassa. — Beudanf s Mineralogy^ p; 333 and 363.
The loss of this ingredient sufficiently accounts for the chemi-
cal difference between the two bodies ; but we are at a loss to
conjecture in what manner such a change may have taken place.

Mr Allan has in his cabinet several specimens from the
trap district near Dumbarton, exhibiting the shape of analcime,
but entirely composed of aggregated crystals of prelinite. Mr
William Gibson Thomson is likewise in the possession of se-
veral exceedingly distinct and instructive specimens of the same
description. There is one, among the former, where preh-
nite, aggregated in globular shapes, is implanted on icositetra-
hedral masses, once of analcime, but now likewise converted
into prehnite. The implanted varieties are green and translu-
cent ; I found their specific gravity e([ual to 2.885 : the por-
tions within the faces of the icositetrahedrons are white and
opaque, and give 2.842, both of them rather lower than the
usual results obtained, which are a little above 2.9, at least in
simple crystals. But the arrangement of the divergent indi-
viduals in the reniform shapes is highly remarkable, and throws

88 Mr Haidingcr on the Parasitic Formation of Miner aU^

some light also on the gradual formation of the new species
within the space occupied by the crystals of analcime. The
centres of the single globular groups, aggregated in a reniform
manner, are situated on the surface of the icositetrahedrons.
From these, the fibres diverge, not only towards the surface of
the globules, but also on the other side, in the direction of
•what formerly was analcime. The original surface of the icosi-
tetrahedrons may be laid bare, by breaking off the exterior
coat of prehnite. Even in those places where there was no
coating of prehnite, the decomposition of the analcime has taken
place in the neighbourhood of other decomposed crystals. The
ingredients of prehnite are silica, alumina, lime, and water;
those of analcime, silica, alumina, soda, and water. There is
no similarity between the two in the mode of combination of
their ingredients, analcime being considered as a compound of
bisilicates of soda and alumina with water, while prehnite is
considered as a compound of simple silicates of lime and alu-
mina, with a hydrate of silica.

On another occasion, Edin. Journ. of' Science^ vol. i. p. 380,
I have described a very curious instance of pyramidal forms,
agreeing as near as possible with those of the pyramidal schee-
lium-baryte, which consisted in their interior of multitudes of
columnar crystals of the prismatic scheelium ore. They were
found at Wheal Maudlin in Cornwall, and are partly implant-
ed on * quartz, arsenical pyrites, chlorite, &c. and partly im-
bedded in cleavable blende. The chemical composition of
the two species is almost identically the same, at least not more
different than in the varieties of pyroxene, or other similar sub-
stances. The chemical formula of the first is Ca W^ ; that of
the second Mn W^ -|- 3 Fe W^, different only in the isomor-
phous bases of calcium in the one, and manganese and iron in
the other, one atom of the protoxide of each of them being
united with two atoms of tungstic acid. This curious resem-
blance of the chemical mixture was then pointed out to me
by Professor Mitscherlich, who supposed, that, from the iso-
morphism of the bases, the varieties observed might be ge-
nuine crystals, of the same ingredients as wolfram, but with the
form of the scheelium-baryte : this was disproved, however,

depending on their Internal Changes. 89

by the observation of the mechanical composition of the mas-
ses. Of itself, the hypothesis is plausible enough that such
was originally the case, and that the cohesion among the par-
ticles was so slight, as to be afterwards overpowered by the
greater crystalline attraction of the same particles in hemipris-
matic crystals, subsequently formed, and as they now apppear ;
in a manner analogous to the decomposition of the common
hydrous sulphates of zinc or magnesia by heat, as described
above. The other hypothesis, that the lime in the original
species has been subsequently replaced by the oxides of iron
and manganese, is rendered more likely by the fact that there
are crystals which in part consist of the scheelium-baryte,
while near the surface, but within the planes of the original
crystals, and where portions of them seem to be wanting, we
observe an aggregate of crystals of the scheelium-ore. A spe-
cimen of this kind I saw at Schlaggenwald, its native place.

Here we must also consider Haytorite, a substance newly
discovered, which has already given rise to various and con-
tradictory hypothesis, and in connection with it some of the
pseudomorphoses of rhombohedral quartz in general. Hay-
torite has been ascertained by Mr I^evy to have the shape of
the species to which he gives the name of Humboldtite. All
those mineralogists who have examined it agree in pronoun-
cing the substance of it to be Calcedony^ which is itself a gra-
nular compound of exceedingly minute individuals of rhom-
bohedral quartz ; so much appears from its physical charac-
ters. Dr Brewster obtained the same result, by ascertaining
its action on light. He has also directed the attention of na-
turalists to the circumstance, that the planes of composition be-
tween the different individuals, and which are always so very
. distinct in Datolite, are as distinct as possible in Haytorite ;
and hence he draws the correct inference, that they cannot
have been formed in a mould, like the pseudomorphoses. — (See
this Journal, No. 1 ^, p. 297 and 301.) Datolite contains a not-
able quantity of silica, 36.5 per cent, according to Klaproth's
analysis. The successive exchange of its contents of lime and
boracic acid for an additional quantity of silica, if it goes so
far as completely to destroy the original species, will transform
the substance of the crystals into a mass of calcedony. There

90 Mr Haidinger mi the Parasitic Formation of Minerals^

is no proof, liowever, that such a process has actually taken
place, so long as we do not discover the remains of the former
species included in the other, testifying the progress of the
change; and we must be the more careful in establishing hy-
potheses, if, as in the present case, we are not led by analo-
gous occurrences in other varieties of the same species.

Calcareous spar is one of those species which are very easily
acted upon by atmospheric agents. The hollow scalene six-
sided pyramids of brown-spar, the macrotypous lime-haloide of
Mohs, consisting of imbricated rhombohedrons with parallel
axes, form a remarkable instance in this species of the replace-
ment of one substance by another, not sufficiently explained
by any of the authors who treat of it, though some of the
observations on which the actual explanation of the appear-
ances is founded, may be traced in several of their writings.
A specimen of a pale yellowish-gray colour in Mr Allan's ca-
binet, of the nature alluded to above, and broken across, in
order to show the inside, presents a cavity, the sides of which
are lined with small rhombohedrons of brown-spar, forming a
surface analogous to the external one of the six-sided pyramid.
But it shows, besides, also the remains of what formerly filled
up the space altogether, of a crystal of the rhombohedral lime-
haloide. The planes of cleavage of this crystal are still visibly
in the same position in which they originally existed, as appears
from the contemporaneous reflection of the image of a luminous
object from the portions of it, now no longer cohering. The
surface of these portions has the same appearance as fragments
of calcareous spar which have been exposed to the corroding
action of acids. Crystals of the brown-spar are likewise de-
posited on some of those portions disengaged from the rest,
and, as it were, pushed off" from their original position by the
gradual increase of the crystals of brown-spar. The mass of
this latter species forms a coating of pretty uniform thickness
over the whole surface of the original six-sided pyramid.
Nearly in the middle of the stratum, wherever it is broken
across, may be observed a whitish, or only rather more opaque
line, of the same colour as the rest, dividing it into two, with-
out producing the least deviation in the faces of cleavage up-
on which it is seen. This line is evidently the section of the

depending on their Internal Changes. 91

original surface of the pyramid of calcareous spar, upon which
one portion of the brown-spar was deposited, while another
portion was formed within the space previously occupied by
the calcareous spar, and destroyed in the progress of decom-
position. The chemical change is here very distinctly indi-
cated ; part of the carbonate of lime is replaced by carbonate
of magnesia, so as to form in the new species a compound of
one atom of each. How this chans^e was^ brouo^ht about is

3^ ""'" «xw^.^.

difficult question to resolve, though the fact cannot be doubt-
ed, as we have, in the specimen described, a demonstration of
it, approaching in certainty almost to ocular evidence. It is
scarcely surprising that such appearances should be visible in
metallic veins, like some of those near Schemnitz in Hungary,
the whole nature of which shows that they must have been
gradually changed by successive revolutions, the uppermost
part being often almost entirely composed of cellular quartz,
which is formed in fissures contained in other species or com-
pound masses, subsequently decomposed, and leaving the
quartz alone. I shall not enter into an inquiry respecting the
probability of such changes in mountain masses, of such an
enormous bulk as the dolomite of the Tyrol, to which Von
Buch ascribed a similar origin. The facts observed on a small
scale do not exclude the possibility of such changes, though
we are certainly less prepared to expect them, where powerful
and momentary revolutions are supposed to have taken place
at the same time, than where any period of time, even the most
protracted, may be granted for the successive replacement of
one particle of matter by another.

Crystals of calcareous spar, previously coated with small in-
dividuals of quartz, often entirely disappear, and leave an
empty shell. We sometimes observe particles of the calcareous
spar with a corroded surface still contained within the cover-t
ing, but much diminished in size. A large pseudomorphosis
in the shape of a scalene six-sided pyramid, from the zinc mines
in Somersetshire, in Mr Allan's cabinet, from which the origi-
nal species of calcareous spar has entirely disappeared, is of a
particularly interesting nature. Beside the superficial coating,
the quartzy matter has introduced itself into the fissures of the
crystal, parallel to its planes of cleavage, and the interior of it

d^ Mr Haidinger on the Parasitic Formation of Miner ah ^

is now not quite empty, but divided into cells by lamelLx^ of
quartz, the cells having the shape of the fundamental rhom-
bohedron of calcareous spar. The formation of what now re-
mains must have begun, therefore, when the original crystal
was still perfect, and have proceeded during the decomposition
of it. The change was gradual, and so we must conceive these
processes to go on in every instance. It is highly probable
that the formation of another species, so near, or even within
the boundaries of a crystal previously existing, will greatly in-
fluence, by its electro- chemical action, upon the arrangement
and composition of the particles of that body.

Quartz, more than any other species, is known to fill up the
vacuities formerly occupied by crystals of calcareous spar, of
fluor, and of gypsum. Such masses of secondary formation
are called pseudomorphoses, and are usually conceived to have
been formed in moulds, arising from a substance which sur-
rounded the original crystals, and was left unchanged, while
the latter was destroyed by decomposition, in a manner similar
to the process of making first the mould of a bust or statue,
and then filling it with plaster of Paris. The cast obtained,
from a mineralogical point of view, is a pseudomorphosis of
gypsum. We have but rarely an opportunity of observing
entire series of specimens illustrative of such a process. Even
in extensive collections, it is difficult to bring together a suffi-
cient number of them, in order to give an example of each
stage of the gradual formation and decomposition of one spe-
cies after the other. The moulds in which many of the pseu-
domorphoses are supposed to have been formed never were
seen or described by any mineralogist ; for instance those of
quartz in the shape of fluor from Beeralston ; those of horn-
stone, in the shape of calcareous spar, from Schneeberg ; those
of calcedony, in the shape probably of fluor, from Trestyan in
Transylvania. We might be inclined to think that actually
there have never been any, but that the new substance was
formed while the old one was disappearing. A film of quartz
deposited on the surface of a crystal, would be the support of
any new matter, subsequently added, as we see in many
instances, particularly the pseudomorphous hornstonc from
Schneeberg, that, like the inside, wherever it is not entirely

depending on their Internal changes. ^ii

filled up, the outside also often shows the reniform and botry-
oidal shapes depending upon the undisturbed formation of the
component individuals. Water, charged with carbonic acid,
and by that means holding silica in solution, may have dissol-
ved the original species, and deposited the siliceous matter in
its stead.

In the varieties from Schneeberg, which consist of perfectly
compact rhombohedral quartz or hornstone, the original out-
line of the decomposed crystals of calcareous spar cannot any
longer be descried. There are varieties, however, also in the
shape of the same species, and consisting likewise of quartz,
where this is still possible ; and among them I know of none
that are more distinct than those from Bristol. The quartz,
in well defined individuals, is deposited partly inside the space
formerly occupied by calcareous spar, producing as many geo-
des or drusy cavities, and partly on the outside of the same
space, the two sets of deposits being separated by the surface
of the original crystal, the only thing still remaining of it.
They do not cohere firmly, but the outer deposit may be re-
moved, leaving the inner one in the shape of perfectly formed
crystals of calcareous spar, the surface of which is stained
brown by oxide of iron. Mr Allan has one in his cabinet,
which he disengaged in this way from the surrounding mass,
terminated on both ends, and altogether showing only a small
portion of its surface, where it might have been attached to an
original support.

In the example just now described, the crystals of quartz
are deposited pretty regularly, at least in so far as their axes
are nearly perpendicular to the surface of the crystals of cal-
careous spar. This is not the case in the prismatoidal man-
ganese-ore from Ihlefeld, which fills up, and at the same time
surrounds, the space formerly containing crystals of calcareous
spar, and where likewise nothing but the surface of the origi-
nal crystals has remained. Both masses, however, are perfectly
alike, and consist of granular individuals, still easily recogniz-
able. Such component individuals are sufficiently small to
withdraw themselves from observation, in the varieties of com-
pact rhombohedral iron-ore from Johanngeorgenstadt in Sax-
ony, and other places, which exactly, like the manganese-ore,

94> Mr Haidinger on the Parasitic Formation of Minerals^

include shapes, or rather surfaces of crystals only, of calcare-
ous spar.

A similar explanation no doubt applies also to the steatite
from Goepfcrsgriin in Bayreuth, well known to collectors, but
as to the causes which have produced it, still unknown to mi-
neralogists. Their perfectly homogeneous appearance excludes
every idea of their being formed by a mixture, however inti-
mate, of steatite, and the species whose forms the crystalline
shapes* affect; for, on this supposition, they still must retain
some of the properties peculiar to those species. The fact that
several forms are found, not only incompatible with each other,
but evidently belonging to other two or more well known spe-
cies, as quartz, calcareous spar, and pearl-spar, likewise dis-
tinctly proves them not to be actual crystals, belonging to the
internal nature of steatite. But if we compare the analogy of
such bodies as those described above, which, like the steatite,
include only the form of another species, we can have no doubt
that all of them must have been formed in the same way.
The chemical composition of steatite is not well ascertained : it
is probably a compound of some silicate and of a hydrate of
magnesia. Quartz is entirely composed of one of its ingredi-
ents ; but the other species, calcareous spar, for instance, whose
crystals have been replaced by steatite, do not contain so much
as a trace of these substances, so that we must suppose them
to have been entirely destroyed, even without giving up part
of their ingredients to the new mixture, while the latter was
forming within and without the space which these crystals oc-
cupied.

Earthy and friable masses are often the result of decomposi-
tion, that is to say, of a change in the arrangement of particles,
which then are so minute, that none of their natural-historical
properties can be ascertained. The pale green friable masses,
in the form of crystals of pyroxene, from Tyrol and Transyl-
vania, considered by Werner as crystallized green-earth, by
Hauy as a variety of steatite ; the red masses sometimes show-
ing the forms of olivine, and dependent upon the decomposition
of that species, included in some of the rocks of Arthur's
Seat, near Edinburgh ; porcelain-earth, probably owing to the
decomposition of the porcelain-spar of Fuchs ; {Denl^schriften

dependiiig on their Internal changes. ^5

der AJcad. der Wissenschaften zu Munchen fur 18J8 und
1819) various kinds of steatite, quoted by authors, some in
the form of garnet, others in the form of trigonal-dodecahe-
drons of an unknown mineral, engaged in the serpentine from
Siberia, others in the form of felspar, &c. yield examples of
such bodies. They have not yet been examined with that de-
gree of attention which they deserve, not so much perhaps on
their own account, as rather for the inferences to which re-
searches of this kind might lead. But it must be allowed, that
many of them cannot be instituted in those fragments of the
entire series, which, for their more apparent distinctness, are
preserved in our mineralogical cabinets. Beside extensive se-
ries of the minerals in question, they require the joint efforts of
mineralogical inquiry, for ascertaining the species which have
been destroyed, and those which have been formed ; of che-
mical examination, for ascertaining the difference in the ingre-
dients of the two ; and of geological observation of the speci-
mens in their natural repositories, in order to establish the
causes by which the chemical affinities, balanced by the forma-
tion of the original compounds, have again entered into action.

From the preceding enumeration, it is but too evident, that
our knowledge of the facts, as well as of their causes, up to this
moment is scanty and imperfect. A wide field of research is
still open, promising a fair return for the labour naturalists
may bestow upon its cultivation. I have endeavoured to collect
only some of the most remarkable and familiar instances of the
changes which may take place in the solid body of a crystal,
the ulterior study of which, while it illustrates the idea of spe-
cies, will throw some light also on the causes of such alterations
as do not appear conformable to the known laws of chemical
affinity, for which we cannot account at least in the present
state of our information.

96 M Raspail's Ex^periments c/n the granules of Pollen.

Art. XV. — Observations and Experiments tending to de^
7no7istrate that the Granules which are discharged in the ex*
plosion of a grain of Pollen^ instead of being analogous to
spermatic Animalcules^ are not even organized Bodies.''^ By
M. Raspail.

This memoir, which ought to form a continuation of the chap-
ter on the vegetable animalcules of Gleichen in my Memoir on
Organic Tissues^ -[- was drawn up at the time when a work'
on the same subject was presented to the judgment of the Aca-
demy of Sciences. As I had obtained results diametrically op-
posite to those of this last memoir, I felt it my duty to put off
the reading of mine, that I might not expose myself to the
suspicion of wishing to influence or retard the judgment of the
Academy. It is possible that I may at present expose myself
to a suspicion of a different kind ; but in the diflicult position
in which my researches have placed me, I must expose myself
to criticism to whichever side I turn, so that the only reason-
able step which I can take is to neglect my own defence, and
enter boldly upon the subject.

I have several times observed the explosion of the grains of
pollen during nearly four years, especially at the time of my
particular experiments upon the subject of pollen ; and I never
observed any thing which appeared to me capable of giving
the slightest idea of the existence of a spontaneous motion.

Nothing is more variable than the circumstances which ac-
company explosion. Sometimes we see issue out of what I
have called the hile of pollen, a vermicular substance which
appears to be formed as if drawn through an aperture. This
is described by Professor Amici under the name of a boyau.
But it is easy to prove that this mass is very often nothing less
than membranous and vesicular ; that it is composed of a sub-
stance insoluble in water ; and which, after the evaporation of
the water, dissolves entirely in alcohol and in ether. Professor

• This impoitant Memoir, which M. Raspail has been so kind as to
communicate to us, will appear in the Memoires de la Societe D'Histoire
Nahtrelle de Paris, torn. iv. It was read at the Institute on the lOlh
March, and at the Society on the Hth March 1828.— En.

t Mem. Soc. Nat. Hist, de Faris, toni. iii. p. 238. 1827.

M. RaspaiPs experiments mi the granules of Pollen. 97

Amici has thus guessed but not proved the existence of a boyato
susceptible of issuing during the explosion of the grains of
pollen ; and I believe I may claim, in virtue of direct and posi-
tive experiments, the discovery of an internal tissue, glutinous
and elastic, which springs sometimes out of the pollen under
the form of a hoyau or of several vesicles.

Sometimes, instead of the vermicular sinuosities of which I
have spoken, there are seen issuing without any order small
corpuscles, very variable in their shape, their aspect, and their
diameter, not only from different vegetables, but even in the
pollen of the same vegetable. In measuring them, it appears
to me that observers have paid attention only to those which re-
sembled one another, and that they had neglected those which
exceeded or did not reach the measure originally observed.
Thus, according to my opinion, they have found that the
globules of blood, and those which compose the tissues, invari-
ably affect the same diameter.

Respecting the spontaneous motion which is now believed
to be found in all inactive substances, I have never observed
the slightest trace of it. The granules issuing from pollen
have themselves an appearance which for a long time made me
doubt their organized nature, and it is to attempt to clear up
these doubts that I have principally made use of the pollen of
the Malvaceae. I shall now proceed to explain, under the form
of corollaries, the various results which I have obtained from
a great number of consecutive observations.

I. A number of causes, of which it is indispensable to exa-
mine the influence, communicate to the most inactive granules
an appearance of spontaneous motion.

Isty The Explosion which discharges the Granules. — The
motion communicated will be the more rapid as the explosion is
more energetic ; and as the medium in which the granules float
has itself received an agitation tending to make a variety in the
level of the surface, it produces different reactions, which will
carry the observed granules in different directions. But this
motion will soon subside by gradual and decreasing oscillations.
2d, Capillarity. — It is very easy to see by the microscope,
that the most inactive bodies perform many various and sud-
den motions during the time they take to become wet The

VOL. X. NO. I. JAN. 1829. G

98 M. RaspaiPs experiments on the granules of Pollen.

grains of fecula, at the instant they reach the water, perform
the part of infusory animalcuh, and the grains of pollen them-
selves then execute motions of recoil sufficiently picturesque up
to the very moment of explosion.

3d, The evaporation of the water which supports the granvr-
les. — As the evaporation causes the level of the different
points of fluids to vary every instant, it is evident that the gra-
nules floating on the surface must from this cause appear to
approach or to retire spontaneously. It is also remarked that
the motions of inactive bodies when observed in the microscope,
will be always in the direct ratio of the elevation of tempera-
ture. An idea may be formed a little exaggerated of the
eff*ects of a similar cause, by placing in the focus of a micro-
scope the inactive granules in a drop of diluted alcohol.

4ith, The evaporation of the volatile substances with which the
granules in issuing from pollen may be impregnated. — These
substances exist in the pollen in great abundance, as analysis de-
monstrates. The bodies which issue during the explosion ought
to be impregnated with them ; but the evaporation of a volatile
substance which covers an inert body, ought evidently to im-
press upon the latter the most illusory movements. In order
to be convinced of this, we have only to throw into the water
of the object-plate, grains of fecula previously moistened with
ether or alcohol.

5^/*, The ordinary motions of great tozvns. — In a populous
city it is hardly possible to make a single microscopic obser-
vation, without remarking a sort of shaking occasioned by the
rolling of the carriages.

6th, The motions caused by the agitation of the air. — This
cause varies according to the currents ; it exists sometimes with-
out the knowledge of the observer, and even when he does not
suspect there is the least agitation in the atmosphere. It is
sufficient for this that the current of air be only at the level of
the object-plate. Even the breathing of the observer renders
the effects still more intense.

7f A, The motions caused by the hands of the observer, occupied
in drawing or leaning upon the table. — This cause of agitation
is so powerful, that it is easy to count with the microscope the
arterial j^ulsations.

M. RaspaiPs experiments on the granules of Pollen. 99

Sth^ The inclination of the object-plate, — It is almost impos-
sible to obtain a geometrical horizontality with respect to the
object-plate of a microscope, and the nearer we approach to
this point of perfection, the more the movements of the cor-
puscles suspended in the liquid are illusory. The liquid ap-
pears to direct itself towards the point opposite to>the side
the most inclined, on account of the inversion of the image ; but
we often then observe two motions in opposite directions, and
lying above each other. If an islet is encountered in the way
of the corpuscles, they are then seen to turn the obstacle by
an act of prudence which can only proceed from a sort of fluid
atmosphere, with which all solid bodies are enveloped in water.
The illusion of a spontaneous motion becomes greater still,
when the islet or promontory is near the limits of the field of
the microscope.

But, however illusory we may suppose these various mo-
tions, it is easy to distinguish them from the motions which
are directed or determined by the will ; it is enough for this
purpose to observe even superficially the motions of the mo-
nads or other infusory animalcules. I should not have been
obliged to enter into these details, if the opinion which I op-
pose had not been revived with a publicity so solemn, that I
felt it incumbent on me to repeat all my experiments, and to
vary them in every way, as if I had doubted the accuracy
of my former ones.

II. For this purpose I made use of the pollen of the Malva-
ceae, not only because it has the greatest proportions, but
also becau&s it has been used to establish an opinion contrary
to mine. Nothing new took place, and if I enter here into some
details, it is less to publish discoveries than to make up for
my former silence, and to pursue the question relative to spon-
taneous motion even to its last entrenchments.

1^^. The grains in issuing from the pollen aflPect different
forms and diameters.

2d. It sometimes happens that two agglutinate together in
order to form a third, whose diameter then equals that of the
two first.

Zd. If several grains join together, they often form a line
more or less crooked or sinuous, which, giving way, appears to
bend, especially when it is met by two opposite currents.

100 M. RaspaiVs experiments an the granules of Pollen.

4fth. Sometimes a certain number of granules put them-
selves in motion towards one of the sides of my microscope,
but I have only to raise the opposite side a little, to make my
little troop retrograde ; and during this retreating movement,
they preserve amongst themselves the same distances and the
same relations, resembling those automatous regiments which
the teeth of the same cylinder cause to pass before the public.
When I cease to raise the side of the microscope, all at once
and by a sudden motion, but without changing the order of
march, they return towards their first direction. But, in ob-
serving the monads, it will be advisable to raise or lower one
of the sides of the microscope; it never makes them perceptibly
change the direction ; they are only seen to struggle in a thou-
sand different ways against the force of the current which draws
them along.

5fh. I have seen some of these grains diminish in size, and
others disappear all at once from my eyes.

6th. At other times no granules are found separately, and
I obtained in the explosion only a mass resembling the sub-
stance of the granules. The pressure of a microscopic point
divided the mass into fragments too large and irregular to be
assimilated to animalcules.

7th. The appearance of my little granules reminded me in
a manner so striking of little drops of resin, half dissolved
in an essential oil, or of oil divided in water, that I could not
prevent myself from entertaining serious suspicions of their or-
ganization ; for the greater or less similarity of their diameters
is not sufficient to alter the opinion of those who have observ-
ed in a microscope the effects of the solution of gum resin in
alcohol. In proportion as this menstruum evaporates we shall
see myriads of globules equal in diameter bubbling up in the
liquid which deposits them and divides them while it is evapora-
ting. Some authors would not fail to see in these motions of eva-
poration something analogous to the Nemazoaires, those mon-
strous assemblages whose singular developement would have
been inexplicable by any known law, had not accurate obser-
vation made them disappear from the pages of science.

III. In order to satisfy myself of the accuracy of the re-
lation which I conceived to exist between the effects of evapo-

M. RaspaiPs experirnents on the granules of Pollen. 101

ration now pointed out, and the nature of my granules, I perform-
ed the following experiment. I placed on a very small drop
of water a grain of the pollen of mallbws. From the instant
of the explosion to the complete evaporation of the water, I
never lost sight of the insulated granules, during all the extra-
neous movements which separated them from the pollen.

When they were applied against the surface of a plate of
glass I left them till next day without deranging the object
frame. Next day they had neither changed their form nor
their aspect, whereas after the evaporation of the water all ani-
malcules collapse, and become flat and crumpled in applying
themselves against the object-plate. My granules then resem-
bled exactly the resin deposited in mamillated masses, and upon
touching them with a microscopic point it made the same im-
pression upon them that it does upon plates of resin softened
by the mixture of a dissolving menstruum.

I now poured upon my little flock a drop of alcohol, when
they were almostinstantly dissolved. But this menstruum makes
animalcules more easily seen, from rendering them opaque by
the coagulation of the albuminous juices with which they are
filled.

The granules which Gleichen first considered as analogous
to spermatic animalcules, are therefore only little drops of re-
sin half dissolved, or of essential oil half concreted.

In this experiment we must take into account all the de-
bris of glutinous or gummy tissues projected out of the pollen
with the granules, and which the use of alcohol renders more
perceptible by coagulating them. They then float in myriads,
and like black points. i

It is on this account that these kinds of experiments ought
to be made by the person who desires to see them, for we
cannot expect to show them to another, for fear of the mis-
takes which could not fail to be committed in changing places.

IV. Having found subsequently that those who are well ac-
quainted with the management of telescopes have very imper-
fect ideas both of the structure of the instrument, and of the
value of microscopical observations, I am compelled to enter
into farther details respecting the precautions which resear-

102 M. Raspairs experiments on the granules of Pollen

ches of this kind require^ and the importance which ought to be
attached to what is called the use of expensive miroscopes.*

1. I have already proved, in my memoir on organic tissues,
that the pollens of different plants vary in the quantity of resi-
nous and volatile substances which they contain. It would,
therefore, not be surprising, if in using any other pollen than
that of the Malvaceae, we should not find so many globules so-
luble in alcohol.

2. In order to recognize the chemical nature of the globules
discharged by the explosion, we must not pour the alcohol on
the object-plate before the evaporation of the water, for in that
case nothing would be dissolved, since the alcohol would ex-
tend itself over the water instead of dissolving the resin.

3. If we wish to stop the movements arising from the eva-
poration of the water, or of the volatile substances with which
it is impregnated during the explosion of the grain of pollen,
we must not content ourselves with covering the water with a
film of mica, for the sides of the film being always unevenly
applied against the object-plate, would not prevent evaporation
at the edges, which would become a still more pow^erful cause
of illusory motions and currents, than if the evaporation con-
tinued to be carried on over the whole surface.

We ought to make use of two plates of glass ground upon
one another, and one of which has a cavity of the form of a
spherical segment. We have then only to put a number of
grains of pollen in the cavity, and after passing water over it,
to slide quickly the one plate over the other. The explosion
of the grains of pollen will at first impress a general motion on
the globules, but the granules will soon resume the immobility
which characterizes them.

4. It may perhaps be objected, that observations opposite to
these, on the animality or the mobility of the granules of pol-
len, have been made with a microscope superior to mine, and

• A celebrated astronomer (See ie G7oZ>e for July) has publicly declar-
ed that cateris paribus the microscope of Amici is superior to every other
microscope, which must mean that the prism which distinguishes it from
others adds to the light and the magnifying power. He afterwards laid it
down as a principle, that the value of microscopical observations was in the
direct ratio of the intrinsic value and the superiority of microscopes.

M. Raspail's experiments on the granules of Pollen. lOS

that they, therefore, deserve more confidence than those which
I have made. * This objection, which could only be urged
by persons little familiarized with the theory and practice of
the microscope, gives me the opportunity of establishing, in
the^r^^ place, that the superiority of microscopes cannot be a
guarantee of the accuracy of an observation ; and, secondly,
that microscopes which are vaunted as superior, are, from
their very construction, inferior, cceteris paribus, to all others.

Leuwenhoek and Swammerdam used the single microscope
with more success than other observers did a compound one ;
and who will venture to pronounce himself more rich in ob-
servations than Swammerdam !

I do not know a single discovery accurately established
which has ever been attributed to the superiority of an instru-
ment, and which cannot be verified with a single lens of a line
focus ; and this is easily explained by considering the actual
state of our means of observation.

I will not speak of solar microscopes, since, with gigantic
magnifying powers, these instruments give outlines too indefi-
nite to permit us to use them in researches which require pre-
cision of form and aspect

It has been sufficiently proved that a microscope is rarely
susceptible of being employed with a magnifying power of from
800 to 1000 diameters, as the light is then weak, and the out-
lines indefinite. With a magnifying power, on the contrary,
of from 200 to 300, a good microscope shows objects with
clearness and distinctness. I shall suppose, however, that with
a power of 1000 diameters, any microscope equals in clearness
and distinctness the magnifying power of 200 with another
microscope ; the difference between the two microscopes will
cease to appear as marvellous, as it at first seems, when we have
once reduced it to its most simple expression, for in this case
the one will really magnify only Jive times as much as the other.

* "We must not forget that the magnifying power itself may become a
new cause of illusion in reference to the automatic movements of inert bo-
dies. As the microscope increases the distance without augmenting the
duration of the motion, it is evident that a motion almost inappreciable
with a magnifying power of 100 diameters, will acquire the rapidity of
lightning with a very high magnifying power.

104 M. RaspaiPs experiments on the granules of Pollen.

But it is well known that the power of 1000 diameters can
never be compared in point of light and distinctness with infe-
rior magnifying powers ; and even if a microscope should mag-
nify 1500 times, the advantage derived from it would perhaps
be inferior to that gained by a single lens, for clearness is un-
doubtedly a great compensation for magnifying power. Of
what consequence is it to show us giants, if we can distinguish
them only in shadow.

On the other hand, the diameter of organs which we re-
quire to study is far from being invariable ; and if a microscope
should not be able to magnify enough to show an organ in one
body, we may expect to meet with the same organ on a large
scale in another body, so that its examination will require only
a small magnifying power. If, for example, we had occasion
to study the fecula in the farina of the small millet, it would
be difficult to make the simplest experiment with a power of
1000, but the potatoe presents us with a fecula examinable by
very inferior magnifying powers. *

The essential advantages consequently which can be derived
from high powers are only ephemeral in relation to natural
history ; and we ought therefore to be on our guard against
attaching to them too much importance.

Supposing, however, that this importance is sufficiently
great to enable us to arrive exclusively at the knowledge of
truth, let us examine the question, whether this privilege
ought to be granted to the microscope of Amici in preference
to every other.

The horizontal microscope of Amici does not absolutely dif-
fer from the vertical achromatic microscope invented by M.
Selligue but in having a triangular prism, the hypothenuse
of which reflects horizontally to the eye-glass the image trans-
mitted by the object-glass. The most superficial knowledge
of optics is sufficient to convince us that, cwteris paribus, i. e.
supposing the two microscopes to have the same system of

• We cannot here agree with our author. The examination of the fe-
cula of the potatoe will never stand in natural history for the examination
of the fecula of the millet, unless the similarity of all fecula hatl been pre-
viously determined. But as this could only be done by the microscope,
the argument of our author has no force. We might as well infer the
structure of the sting of minute animals from that of the enlarged organ
in the wasp. — Ed.

M. Raspail's experiments on the granules of Pollen. 105

object-glasses and eye-glasses, and taking care to observe with
the same magnifying power, the mere addition of the prism
renders the microscope of Amici inferior to every other micro-
scope, since there must be at the three surfaces of the prism a
triple loss of the luminous rays. But at present these two
kinds of microscopes are constructed with the same lenses, so
that my supposition is realized, and the comparative experiment
may be made. I request, however, those who desire to be convin-
ced with their own eyes, to observe with the same magnifying
power, and not to trust to the tricks of certain artists, who
exaggerate the magnifying power of a microscope in order to
sell it at a high price.

With regard to the experiments in support of the fact
which theory establishes, they have been repeated in Eng-
land before M. Amici with his own microscope; they have
been repeated in France with an instrument made by M.
Amici, and recently arrived from Modena for a member of the
Institute ; and they have been repeated by the most skilful
and the oldest observers of the capital ; and it has been proved
that many objects — for example, the semen masculinum desic-
catum, — are not perceivable by the microscope of Amici. *

These sort of revelations, perhaps indiscreet, hdve appeared
to me necessary, not only for the interests of science, but even
for those of the arts, especially since my humble labours have,
as I am informed, introduced the use of the microscope into
a number of manufactories and laboratories. They appear to
me necessary in reference to the interest of those young ob-
servers whom nature has favoured more highly than fortune,

• In the meeting of the Academy of Sciences of the Uth August 1828,
M. Arago, in attempting to reply to these facts, the accuracy of which we
do not scruple to guarantee, has maintained that we may render these ob-
jects visible by the microscope of Amici by drawing out the tubes and
making the object approach to the object-glass, — a thing which we have
tried in all ways, but without success. Besides, these objects are not in-
visible in this microscope, on account of their smallness, but on account of
their transparency, and of the indistinctness of their edges. But the more
you draw out the tubes to magnify the diameter, the more indistinct do
these objects become, since you thus increase the loss of a great quantity
of the rays of light. The simplest experiment on this subject will serve as a
reply to the assertion, no doubt unpremeditated, of this learned astronomer.

106 M. RaspaiPs Note on Mr BroimCs Observations.

and who would no doubt be every day discouraged by the er-
roneous expression with an expensive, a powerful, and a fine
microscope.

In justification of my conduct in this matter, it will be suf-
ficient to mention the following fact : —

A manufacturer of painted papers having learned the use
which I had made of magnifying glasses in the analysis of the
fecula, and of the encollage a la cuve, and, deceived by pom-
pous announces in the Journals, eagerly purchased for 1200
francs a microscope of Amici''s. If he had done me the honour
to consult me, he would have devoted 1185 francs to the pur-
pose of his manufactory; for by the side of my costly micro-
scope of M. Selligue"'s, I would have shown him the poor
mounted single lens which has served me for all my researches
on the fecula and on the encollages a la cuve ; and I boldly
hold out a formal defiance that a more expensive instrument
will find a single point of these experiments erroneous.

Art. XVI. — Note on Mr Brown^s Microscopical Observations
on the active Molecules of organic and inorganic bodies. *
By M. Raspail.

The Society has heard at its last meeting the contents of a
work by Mr Robert Brown, entitled, " A brief account of
Microscopical Observations on the particles contained in the
Pollen of Plants,'''' f &c. Such of our members as attended to
the discussion which took place at the Institute on the subject
of my Memoir On the granules discharged in the explosion of
a grain of Pollen, which was read on the 18th March 1828,
cannot fail to have observed, that the general proposition of Mr
Brown is contained in that Memoir; and philosophers will
doubtless acknowledge that the phenomena of motion, which
Mr Brown left enveloped in a sort of mystery, by represent- ^
ing them as inherent in the molecules of organic and inorganic
bodies, may be easily explained by the concurrence of all the
foreign circumstances which we have enumerated in the pre-

• This Note was read to the Society of Natural History of Paris on tlie
29th August 1828, and forms an appendix to the preceding Memoir.
f Printed in our last Number, p. 336.

M. RaspaiPs Note on Mr Brown's Observations. 107

ceding memoir. The author might have swelled his memoir
with myriads of analogous facts ; but we consider it unneces-
sary to adduce individual facts after the general law has been
ascertained.

The author might thus have varied infinitely the motions
which he has observed, if he had used essential oils, globules
that had been kept in ether, or alcohol, or camphor, all whose
motions vary with the shape of the fragments which are pla-
ced upon the water, since they are owing to the evaporation
of the substance itself. To all these causes we may add the
electricity which the friction of the file may communicate to
metallic particles.

Mr Brown would no doubt have himself recognized the
various causes of these motions, if he had seen the criticism
which we have published of a Memoir, Sur les Mycodermes^
(Bull des Sc. Nat, et de Geol. Tom. xii. No. 27, p. 46 ;) — our
Note, Sur VEncollage a la Cuve^ read to the Institute on the
24th December, and published in Le Globe the end of De-
cember 1827; — our Memoir, Sur les Tissus Organiques,
published in Tom. iii. of the Memoirs of the Natural History
Society of Paris ; and, lastly, the announce of the same Me-
moir, inserted in Le Globe of the 22d March 1 828, four months
before the publication of Mr Brown's memoir. This article
was reprinted verbatim in the Bulleti7i des Sc. Nat. etde Geol.
for May 1828, No. 54.

In order to render these motions visible, the microscope is
not indispensably necessary. Whenever we place upon water
organic or inorganic bodies capable of being wetted, or of im-
bibing water, we shall observe motions more or less singular,
which will vary in each experiment, and which will depend
only on the variations in the form of their different faces.
Particles of iron, for example, will move differently, according
as they have been obtained with a file more or less fine. Po-
rous bodies will move very differently from compact bodies.

Those which have no affinity for water will move when the
water is agitated by the causes which we have pointed out in
our preceding memoir. Thus wax well freed from its vola-
tile oil, fat, and oil, present motions too vague to be deter-
mined. But dry organic fragments, on account of their avi-

108 Physical Notices of' the Bay of Naples.

dity for liquids, present the most picturesque movements, for
the coiled up fibres uncoil themselves, folded membranes will
stretch themselves, and empty vesicles will be filled — effects
which cannot take place without motions and agitations. To
complete, in short, so many wonders, if we place upon water the
molecules of a carbonate, of the debris of shells for example,
and add an acid to the liquid, we shall imagine that we have
before our eyes a kind of artificial fire-works, and shall see
fuses flying in all directions.

I shall conclude this note by observing, that the discovery
of a membrane, which lengthens itself en bo?/au, or into a cy-
lindrical mass of the pollen, does not belong to M. Brongniart, as
Mr Brown seems to announce, but to our Memoir e sur les tis-
sue organiques, as may be shown by merely reading the proces
verbal of the meeting of the 21st July 1826, of the Natural
History Society, and printed in the Bull, des Sc. Nat. et de Geol.
Tom. X. 176, — a paper which is six months anterior to the me-
moir quoted by the learned English author. If Mr Brown
will have the goodness to repeat our chemical experiments on
this subject, he will be convinced that nothing is more cer-
tain than the existence of these internal membranes of the
pollen.

Art. XVII. — Physical Notices of the Bay of Naples. Com-
municated by the Author.

No. II. — On the Buried Cities of Herculaneum, Pompeii, and

Stabice.

**■ Inde legit Capreas, promontoriumque Minervae

Et Surrentinos generoso palmite colles,
Herculeamque urbem, Stabiasque et in otia natam

Parthenopen . "

Ovid.
" Hie locus Herculeo nomine clarus erat,
Cuncta jacent flammis, et tristi mersa favilla."

Mart.

In No. I. of the Physical Notices of the Bay of Naples, we
took a rapid view of the most remarkable feature it contains,
Mount Vesuvius,— of its topography, phenomena, and produc-

No. II. — Herculaneum, Pompeii, and Stabile. 109

tions. It seems most natural to proceed next to an account of
by far the most extraordinary effect of its volcanic agency now-
extant, the cities buried under its ejected materials, and now,
after a repose of between seventeen and eighteen centuries,
opened to the view of mankind, and calling them to survey, in
a form more forcible than words can paint, the habits, the pe-
culiarities, the domestic comforts, the public luxuries, the
baths, the theatres, the villas, and the tombs, of another age
of men ; a scene which opens a sort of enchantment to us, pre-
served as by a miracle from that slow but ruthless power, which
in the meantime,

" So oft has swept the toiling race of men,
And all their laboured monuments, away."

In a subject like this, I shall be excused for not adhering
rigidly to the physical appearances which the buried cities now
present to the eye of the naturahst. I shall be permitted to ex-
tend some remarks to the ancient history of these ill-fated towns,
the event by which they w^ere overwhelmed, and the illustra-
tions of antiquity which their excavation presents.

The authorities to which I can refer in my present work are
much more abridged and unsatisfactory than when writing on
Vesuvius ; and if in combining the results of my personal ob-
servation with the remarks of others, I may appear desultory
in my arrangement, I must crave the indulgence of the reader,
in consideration of the remarkable want of any work on the
physical history of the objects I have undertaken to elucidate,
and the numerous sources to which I must be indebted for
facts in almost every page of the narrative. Pompeii and
Herculaneum have been peculiarly unfortunate in the de-
scriptions of all classes of travellers. While some with Eustace
confine themselves to a detail of classical and sentimental ex-
pressions, which, however interesting to the visitor, and how-
ever they may press themselves on his attention, cannot be suf-
ficiently varied in expression to please the public ear, told as
they are for the twentieth time ; others, with Barthelemy, Cay-
lus, and Mazzochi, have dwelt chiefly upon the benefits, every
day becoming more problematical, to be derived from the dis-
covery of papyrus rolls; and a larger number give merely ca-
talogues of the more remarkable features of the excavated

110 Physical Notices of the Bay of Naples,

buildings, with Stark, Ferrari, and Reichard ; or of the objects
of domestic use and ornament removed to the museums, of
which a splendid account has been published, in nine volumes
folio, under the title of " Antichita di Ercolano.'''' Here we may
in vain search for any information of a general description, to
be found only in some travels of an older date, such as those
of Lalande and Swinburne, which contain more general informa-
tion on the extraordinary phenomena of the buried cities, than
the passing and unsatisfactory notices of all that Piozzi, Ba-
retti, Brydone, Nugent, Douglas, Smith, Walker, and others
perfectly innumerable, have brought together, in those volumes
which, large as is their collective bulk, are but a mite towards
the great desideratum of a truly philosophical and complete
description of Italy. Nor have those whose province has been
more peculiarly philosophical acquitted themselves better in
this respect ; Breislak, whose valuable " Topographia Fisica di
Campania'''* was so often quoted in my paper on Vesuvius, bare-
ly mentions as objects in the topography of the bay these re-
markable victims of volcanic agency, nor gives us a word of
that information which, in a work approaching in its nature to
the present " Notices," we might have expected. Spallanzani,
one of the few native geologists of Italy, in his four volumes
devoted to the natural history of the two Sicilies, hardly
mentions the names of Herculaneum or Pompeii ; and Delia
Torre, in his History of Vesuvius, though obliged in the
course of his details to allude cursorily to the subject, is singu-
larly trifling in his notices, which he frequently repeats in al-
most the same terms in the ceurse of his work.

On the whole, our most satisfactory guide is Hamilton, in
his Campi Phlegrcei; yet how meagre and confined is the view
he gives of the subject ; how short his statements ; how incom-
plete his general views ; and what a deficiency in many of the
facts we would wish to be possessed of. Among the desiderata
et desideranda in our present subject, we may consider the in-
vestigation of the ancient sea line, extending from the modern
Resina to Castel-a-mare ; the enumeration of the strata which co-
ver Herculaneum ; and the results relative to the ancient con-
dition of Stabiae which its excavation must have illustrated, but
which we shall presently see is even now a matter of great de-

No. II. — Herculaneumy Pompeii^ and Stahice. Ill

bate. Upon these, and a variety of other topics, Hamilton is
entirely silent ; but his account is important, as being more ori-
ginal than those of other travellers, and forming an appendix
of value to all the accounts which have met my eye.

Upon the whole, I do not despair, within the limits of this
short paper, of giving the substance of all that has yet been
given to the world in the way of physical facts, regarding the
phenomena of the buried cities. I propose to commence by
noticing the original condition of these towns as far as bears
upon their subsequent catastrophes ; next to give an account of
the event by which they were submerged, examining the ac-
counts which the ancients have left us upon the subject, more
particularly as they are connected with present appearances ;
and finally, to describe the existing condition of the cities as
they now stand, and the circumstances connected with their
disinterment, as modified by past events, and calculated to
throw light on volcanic agency. >

To commence with the original condition of Herculaneum,
Pompeii, and Stabiae, we may remark, that, from decisive clas-
sic authorities, they appear to have stood in the order just
named from W. to E. along the shore of the Bay of Naples, as
is expressed in the motto at the head of this paper, taken from
Ovid, and in the two following inscriptions from monumental
itineraries given by Cluverius.*

Neapoli

Herclanium xi. Herclanium

Oplontis vi. Oplontis vi.

Pompeis iii. Stabios iii.

Nuceria xii. Nuceria xii.

Hekculaneum, it is generally admitted, derived its name
from Hercules, who was supposed to be its founder, for which
Strabo is the principal authority; but it would be superfluous
to enter here into the details connected with its early history,
which, however, Bajardi in his great work seems to have found
so entertaining, that in the two first volumes of his " Anti-
chita di Ercolano^^'' amounting to 1100 pages quarto, he has

• Italia Antigua, Fol. ii. 1154 and 1155. The reader may also consult,
for the position of these towns, Strabo 1. v. Florus 1. 16. Velleius 1. xi. Pliny
iii, 5. Columella 1. x. Mela xi. 4.

112 Physical Notices of the Bay of Naples.

got no farther in his history than the expedition of Hercules,
in aid of Theseus before the foundation of this city. It will be
sufficient simply to mention the conjecture of Mr Hayter (we
presume the gentleman who since superintended the unrolling
of the papyri) the ingenuity of which scarcely makes up for
its improbability, that Herculaneum is derived from two orien-
tal words, Her and Koli, signifying " burning mountain."
Be this as it may, Herculaneum seems to have been peopled
by a Greek colony, but not to have risen to eminence till later
times, since Polybius, 150 years B. C. when mentioning Capua
and Nola, does not allude to it. It afterwards became, how-
ever, distinguished for its splendour and refinement, and " if
we are to judge from its remains,"" says Ferrari, " we must be-
lieve that it had been the most remarkable city in Campania
after Capua and Neapolis." It certainly was much admired by
the Romans from its situation and climate, and we have rea-
son to believe that it contained many of their most favourite
villas. Yet it must be admitted that it is rarely and cursor-
ily mentioned by authors who were contemporary with its days
of magnificence, and that its name would hardly now have
reached the attention of the learned, but for the remarkable
catastrophe of which it was the subject and the scene.

Antiquaries, previous to the eighteenth century, were not
agreed as to the site of the ancient Herculaneum. Cluve-
rius, in his " Italia Antiqaa^ inferred from the Monumen-
tal Itineraries already cited, that the number xi. there
given as the distance between Naples and Herculaneum was
a mistake for vi. ; since he remarks that the total distance from
Naples to Pompeii was xx. by that reasoning, whereas the dis-
tance to the river Sarno, which was known to have passed
Pompeii, was found to be only xvi., whence he fixed Hercu-
laneum close to Torre del Greco, seated on a small promon-
tory at six miles from Naples, which, on its discovery, proved
to be very correctly the spot. The harbour of Hercula-
neum (for it was a sea-port,) existed on both sides of the pro-
montory, and on both a stream appears to have flowed into
the sea, as we learn from Sisenna, an old writer, quoted by
Nonius Marcellus, and who flourished in the first cent. B. C.
The country in the vicinity was then probably much flatter,

No. II. — Herculaneum, Pompeii, and Stabice. 1131

and free from the accumulated ejections of Vesuvius, since we
learn from Columella that there were salt pits in the vicinity
of the city.

" Quae dulcis Pompeia palus, vicina salinis
" Herculeis "

PoMPEiT was seated on the river Sarno, a fact which appears,
before the discovery of the cities, to have thrown the greatest
light upon their true position. The river still flows, though
probably changed from its old course, divided into two bran-
ches, and passes near the modern village of Scafati, to the east
of Pompeii. This city was probably larger, and more im-
portant than Herculaneum. Seneca {Nat. Qucest. vi. 1.) calls
it " Celebrem Campaniae urbem ;*" while PHny and Tacitus in-
form us that it was a municipal town. On the other hand, we
have reason to believe that Herculaneum was considered a small
one, from the authorities of Sisenna, Dionysius, and Strabo.* In
this view it is interesting to know what was its real size, which
we have now sufficient data for accurately determining. The
walls of Pompeii are above three miles in circumference.

Some modern writers have, I think, derived the name from
the Pompeian family ; but we have every reason to believe the
city to be far more ancient than to render this opinion probable ;
and Solinus expressly refers it to the triumphs (pompce) of
Hercules, when, on his return from Spain, he founded the
city which bore his own name. Although the exploits of
Hercules rank among the fables of mythology, we are not to
carry our incredulity so far as to imagine that there was never
a foundation for these relations, or to invalidate the testi-
mony of antiquity with regard to traditional etymologies.
The name has been variously spelt ; Pompeii, Pompeia, Pom-
pejes, Pompei; but I have adopted the first, not only as war-
ranted by the best English authorities, but as being apparent-
ly the true nominative of the Latin (plural) appellation. Pom-
peii was anciently a sea-port, as we learn indirectly from clas-
sical sources, -j- but especially from the obvious arrangements

• Cluverius. This goes against the opinion of Ferrari, already cited,
who considered Herculaneum the third city of Campania.

t The most remarkable authority I am acquainted with is that of Livy,
who mentions a Roman fleet being driven into Pompeii, and dispersing
marines to the plunder of the Nucerian territory. " Classis Romana in

VOL. X. NO. I. JAN. 1829. H

114 Physical Notices of the Bay of Naples.

made for embarkation and the management of merchandise
displayed by the excavations ; but the same event by which
the city was destroyed, forced the sea outwards by the accu-
mulation of volcanic soil, to the distance of a mile, — a striking
proof of the real magnitude of the catastrophe, and at the
same time easily credible, when we recollect that the neigh-
bourhood was an extended plain, little elevated above the sea,
and giving rise to the " palus Pompeia," mentioned by Colu-
mella in the lines already quoted. Pompeii, as well as Her-
culaneum, stood on the sides of Mount Vesuvius, but at a con-
siderable distance (5 miles) from its present crater, and the
former one was probably greatly farther off; and this is rather
sanctioned than otherwise by Pliny the elder, * in his expres-
sion " Neapolis, Herculanium, Pompeii ; baud procul spec-
tante Monte Vesuvio ;" for as he speaks of these cities nearly
in a similar situation with regard to the mountain, if we sup-
pose the crater to have existed considerably to the north of
the present one, as in my last paper I showed was probable,
the distances are more nearly equalized.

The situation of SxABiiE was very different, being placed
at the base of the Surrentine range of hills, composed of
Apennine limestone, and a branch of the great chain which
passes through Italy. It was near the site of the modern
Castel-a-Mare, between the flank of the hills and the sea-shore.
Its situation was known to Cluverius long before the time of
its discovery. Its neighbourhood was peculiarly remarkable
for hot medicinal springs, of which Galen,f Cassiodorus,J and
Pliny,§ have given an account. Even in modern times these
springs remain, and an account of them has been published by
Raimondo de Majo. || Of Stabiae we know little as a town,
and its history has been a subject of some dispute. Certain it
is that it was of great antiquity, as it is said to have been]
founded by the Osci, and successively inhabited by the Etrusci, j
Pelagi, and Samniti. We have the distinct testimony of the
elder Pliny, that it was destroyed by Sylla in the civil wars,]

Campaniam acta et adpulsa Porapeios esset, socii inde navales ad depopu-
landum agrum Nucerium profecti." (Lib. ix.)

" Lib. iii. cap. v. t De Meih. Medendi, lib. v. J Lib. xi. Epist. x.

§ Lib. xxxi. 2. II Napoli, 1745. 8vo. See Ferber.j

No. II. — Herculaneum, Pompeii, and Stabice. 115

and under the consulship of Cn. Pompeius and L. Carbo.
Cluverius finds, however, no such name as Carbo in the con-
sulship along with Pompey ; and we must therefore believe the
reading corrupted for Cato, who was consul, which will place
it in A. U. C. Qi6^. Thus far all is clear ; but now the diffi-
culty in the history commences, and there appear to be three
opinions regarding the final fate of Stabiae. By some it is
supposed that it never rose after the destruction by Sylla;
others consider it to have been rebuilt, and then destroyed by
the eruption A. D. 79 ; while a third party maintain that it still
existed in the sixth century. Each of these opinions has some
weight, and the evidence is rather contradictory. Breislak,*
in the few words he says on the subject, supports the first.
After mentioning the opinion that it was destroyed by the
eruption under Titus, he says, " Pline^ 1. iii. c 5, la renverse
formellement lorsqu'il dit que c''est sous le consulat de Cn.
Pompee et de L. Carbon, Fan QQ^ de Rome, que Stabia fut
detruit par Sylla, et qu'il nous apprend que de ces mines il se
forma plusieurs villages." Eustace *(- is nearly of the same
opinion ; " Stabiae, now Castellamare di Stabia, had in Pliny's
time disappeared as a town, and given place to a villa. It was
destroyed by Sylla, and never seems to have revived ; quod
nunc in villam abiit, Plin. lib. iii." The reading of this im-
portant passage of Pliny in the best variorum edition J; is as fol-
lows :— " In Campano autem agro Stabiae oppidum fuere usque
ad Cn. Pompeium et L. Carbonem consules pridie Calend.
Maii, quo die L. Sylla legatus bello sociali id delevit quod
nunc in villas abiit" As a various reading, however, in the
margin we have " villam" for " villas," which certainly I
should rather be disposed to translate a " small town" than a
" villa," as Eustace has it ; and if we retain the original read-
ing of " villas," we should render it " villages,'"* which is the
meaning adopted by Breislak, Swinburne, and Lalande. But
besides this, the younger Pliny speaks of it as still existing, in
the famous epistle relating the fate of his uncle ; § so that I
cannot at all coincide in the idea that Stabiae was finally and
irrevocably destroyed by Sylla. The second opinion, that it

* Campania, i. 26. t Tour, iii, 127.

% Lug. Bat. 1669. 3 vols. § Epist. lib. vi. Ep. 16.

116 Physical Notices of the Bay of' Naples.

was buried by the eruption of A. D. 79, along with Hercula-
neum and Pompeii, is the most general, though not very dis-
tinctly warranted by classical authority. We are, however, dis-
tinctly informed in the remarkable epistle of Pliny just quoted,
that the ashes fell in such quantity, that at the time of his uncle's
death at Stabiae, they had almost filled the adjoining court of
the house in which he was, — an irrefragable proof of the mag-
nitude of the catastrophe, especially when taken in connection
with the imperfect modern accounts we have of the excavation
of the ruins. Hamilton * mentions the state of the covering
soil indirectly, by observing that the ejected masses of scoria
at Pompeii weigh sometimes eight pounds, but at Castel-a-mare
never above an ounce. From the only circumstantial ancient
account of the phenomenon, therefore, we have reason to be-
lieve Stabiae to have been overwhelmed. A second argument
in favour of this opinion arises from the style of the objects
dug from its ruins, which, if I mistake not, closely resemble
those from Herculaneum and Pompeii. At least, the dissimi-
larity must have been glaringly obvious had they borne a date
so far back as the year 89 B. C, or so late as the sixth century
of our aera, according to the two other hypotheses. A third
evidence that at least it did not fall to natwral decay during
the middle ages, is derived from the fact, that skeletons and
personal ornaments have been found among the remains,
though very few,-|- but a considerable number of papyrus
rolls. Lastly, the present appearance of the excavations, as
far as the imperfect accounts we have go, (the work being al-
ways filled up as they proceed,) and not having been on the
spot myself, I must be satisfied with these accounts, — the
modern excavations correspond perfectly to the idea of a vol-
canic eruption ; and in fact it is almost incredible that any other
event could produce a similar effect. I shall state the appear-
ance of the locality towards the close of this essay.

The third hypothesis which I have already been combating,
that Stabiae existed till the sixth century at least, is supported by
Cluverius,j who confirms my opinion of a new town having risen

* Campi Phlegrceiy i. 57.

+ " Pochissimi Spheletri" — " pochissimi mobili preziori," — Ferrari,
Guida di Napoli.

X Italia Antiqua, ii. 1159 — 1161.

No. II. — Herculaneum, Pompeii, and Stabice. 117

upon the ruins of that destroyed by Sylla. He founds it upon
a passage of Symonachus, * bearing a date of about 380 years
after our aera, which describes Stabiae as still in existence ; and
another of the " Historia Miscellanea,^'' -f under Justinian, 150
years later, in which occurs the remarkable expression, " villa,
quae Stabii dicitur.'' It is sufficiently remarkable that the very
same word " villa" should have been employed by this late
writer as by Pliny in reference to Stabiae, which would certain-
ly rather incline me to the opinion I have already stated, that it
might be put for a village even in the Augustan age, although
Ciuverius \ pronounces it a modern barbarism. At all events,
without entering into a philological dispute, the reading of
" villas" in Pliny may supply us with the idea of a string of
detached houses forming a village; which from Swinburne,
who saw the excavation going on, we learn to be much the
true appearance. § With regard to the existence of Stabiae in
late times, the authorities are certainly somewhat perplexing.
Yet we cannot, for the reasons already alluded to, relinquish
the belief in the fate of Stabiae under the eruption of 79- It
only remains, therefore, to suppose, that, from the great dis-
tance of the mountain,- and the comparatively slight desolation
which the country round had experienced, a new village had
speedily risen on the site of the former one.

It is now time to notice briefly the phenomenon by which
the cities of Herculaneum, Pompeii, and Stabia? were de-
stroyed. The event was one sufficiently novel and surprising
to ensure us some account of it from an age even less scientific
than that of Titus ; yet in some of the facts connected with it,
especially regarding the fate of the Campanian towns, we are
left in remarkable uncertainty.

The letters of Pliny which relate the death of his uncle in
the eruption of a. d. 79, are addressed to his friend the histo-
rian Tacitus, from whom we might have expected some cir-
cumstantial details of the event ; but unfortunately the part of
his history to which it belongs has been lost. Our principal

• Italia Antiqua. vi. 17. I Lib. xvi.

:|: " Vocabulo villw utitur more sui aevi pro vico ; ut hodieque fit per
omnera Europam ab iis qui Latino barbare loquuiitur aut scribunt."
§ Travels, vol. i. p. 128.

118 Physical Notices of the Bay of Naples,

authorities, therefore, are the Epistles of Pliny, and the Epi^
tome of'Diori's History by Xiphilin. Preceding this remark-
able event, a great earthquake took place in the year 63, of
which Seneca gives us a particular account, mentioning that
Pompeii was excessively injured, and a part of Herculaneum
destroyed ; * and Tacitus expressly says, " Motu terrae cele-
bre Campaniae pppidum Pompeii corruit." -f- This event
proved only the forerunner of one more tremendous. Pliny
relates, J that the ninth day before the Kalends of September,
A. D. 79, at the seventh hour, corresponding to the 24th of
August, at 1 p. M., a cloud of very unusual shape was observed
to rise from Vesuvius, resembling in form a pine-tree, (the stone
pine of Italy, with a tall stem and expanded flat head), — a simile
which corresponds so exactly with observed appearances, as to
be still the usual object of comparison for the cloud which con-
stantly ascends previous to an eruption. Its form is clearly
owing to a cause which Pliny pretty distinctly points out, that
where the force of projection is exactly counterbalanced by the
decreased density of the air, combined with the loss of original
impetus, the particles for a short time must remain pretty near-
ly in equilibrio, and, therefore, liable to be acted upon by the
wind, which is very commonly violent at such moments. From
the great height of the extended part of the cloud of ashes,
that impalpable powder is carried sometimes to immense dis-
tances, § and the more ponderable masses are discharged in
large quantities near the foot of the mountain. The pheno-
menon, therefore, so well described by Pliny, corresponds per-
fectly to the precursor of a prodigious " cenere^'^ or shower of
ashes. The elder Pliny, resolved to investigate this extraordi-
nary phenomenon, was just leaving his house at Misenum to
cross the bay to the scene of danger, when he received letters
from Rectina, the wife of Nascus, who had a villa on the shore
below Vesuvius, entreating his assistance in that awful mo-
ment. II He set sail, but was unable to pursue his purpose,
not only from the enormous masses which rolled from the

« Nat, Qjuocd. vi. 11. t Ann. xv. 22. % Epist. vi- 16.

§ See last Number, p. 206.

II The reading of this disputed passage I have taken from the famous
Aldine edition of 1508.

No. II. — Herculaneum, Pompeii^ and Stahice. 119

mountain, and the showers of pumice, but from the sudden
retreat of the sea, (vadum subitum^) — another feature of the
description which exactly corresponds with modern observa-
tion. In this dilemma, instead of turning back as the pilot
advised, he ordered him to proceed to his friend Pomponianus
at Stabias. Here he remained the afternoon, and observed broad
flames spreading from the mountain, (e Vesuvio monte in plu-
ribus locis latissimce Jlammce et incendia relucebant,) which
Delia Torre * supposes to have proceeded from the stream by
.which Herculaneum was destroyed. Here, (at Stabiae,) after
.supper he went to rest, but was obliged to be roused, from the
quantity of stones and ashes (cinere missisque pumicibus)
which filled the court next which he lay. The roofs shook with
earthquakes ; they therefore went into the open air, but found
the shower of stones so abundant that they tied pillows and
napkins round their heads. Proceeding to the shore, the sul-
phurous fumes became so strong as to affect Pliny, who was
of a full habit of body, with breathlessness, and he was short-
; ly after stifled by them. Meanwhile at Misenum, where the
younger Pliny remained, the shocks of earthquakes became
more vehement. He observed more minutely the regress of the
sea; " Certe processerat litus, multaque animalia maris in
siccis arenis detinebat."" He then mentions the tremendous
lightning, which appears to have proceeded from a black
cloud, extended as far as Misenum, no less than sixteen miles
from the volcano, — a phenomenon which, to more or less extent
is almost universal in the case of eruptions ; *[- and this remark-
able account of its extension from a credible eye-witness tends
to render it probable that this catastrophe is unequalled in the
Vesuvian annals. Pliny goes on to give an animated account
of the tremendous scene which the descent of the ashes pro-
duced, and which he mentions were in such quantity, and of
a white colour, as to resemble a deep snow in the morning.
We shall not, however, follow him more minutely in his de-
scription, of which we have given all the leading facts. |
Now it is very remarkable, that in this description we have

* Storia del Vesuvio. 4to. Sect. 71.

I See Hamilton's Campi Phleg, i. 30 ; and this Journal^ No. xiii. Art. ii.
; + The whole will be found in his Epistles, lib. xvi. 16 and 20.

Ijte Phyi^al Notices of the Bay qf Naples.

not a word either of Herculaneum or Pompeii, and this si-
lence has given rise to one of the most extravagant conjectures
which modern archaeology can afford. During the mania of
the French Revolution, when nothing was too sacred or too
well established not to be re-examined by the newly enlighten-
ed eye of "la grande nation/' Citoyen du Theil chose to
maintain that the two cities above named did not perish in the
eruption of 79 but by one four centuries later. The report
of Villar, the secretary to the Institute, upon this paper, will be
found in the Abbe Barthelemy"'s Travels ; from which it ap-
pears that the arguments in favour of this opinion are the un-
supported assertion that these cities existed under Adrian ; that
the characters of the inscription under the statue of Balbus
do not belong to the age of Titus ; that there is an indication
of the existence of Herculaneum and Pompeii in a fragment
attributed to Petronius Arbiter ; and that they are noticed in
a fragment known under the name of the Map of Pentiger ;
but not being found in the itinerary attributed to Antoninus,
it is presumed they were destroyed by the eruption of 471.
Somewhat more classical authorities are to be found in sup-
port of the received opinion ; in fact, the only truly classical
indications correspond with this idea. Dion Cassius, the his-
torian, who flourished about the 230th year of the Christian aera,
expressly informs us, * that in the reign of Titus, the great
eruption of Vesuvius ejected such quantities of ashes, as not
only to kill many men and cattle, and to reach the very shores
of Egypt and Syria ; but that it entirely overwhelmed both
Herculaneum and Pompeii, even while the people were sitting
in the theatres. It appears, however, from the excavations
and the small number of skeletons discovered, that if they
were in the theatres at the commencement of the eruption,
they must have found time to escape. No authority of which
we are possessed can invahdate a testimony so distinct and cir-
cumstantial as that of Dion, combined with the probabilities of
the place and collateral evidence. That the eruption of a. d.
79 was competent for the purpose I think has been already
shown, especially when we consider its influence on Stabiae and
Misenum at such great distances from the volcano.

* Dion ap. Cluver. ii. 1159.
4

No. II. — Herculaneum, Pompeii, and Stabioc. 121

The argument of the Frenchman, founded upon the cha-
racters of the inscription below the statue of M. Nonius Bal-
bus, I consider the most erroneous of all. I do not very pre-
cisely recollect these letters; but I would simply ask if it is
within the bounds of possibility, that a statue like that of Bal-
bus, which has been allowed by judges to equal or even ex-
ceed the exquisite one of Marcus Aurelius on the capitol at
Rome,* should have been a production of the decline of the
empire and of art ? I have devoted not a little time and
care to the study of the forms which the characters of in-
scriptions assumed in different ages ; I have copied many of the
most remarkable in the excavations of Pompeii with my own
hand, and carefully compared them with those of different
ages, and with others more especially known to be of the age
immediately preceding the reign of Titus, and I do not hesi-
tate to declare, that I have not observed one from the buried
cities which does not correspond to the period between Augus-
tus and Vespasian, — a period in which the characters are so
marked, as in general to prevent the possibility of confusion
with those either preceding or following. With this statement,
which I could easily substantiate by instances, I shall content
myself at present, and will only add, that, had these cities last-
ed till the fifth century, they must have been filled with bar-
barisms of sculpture and masonry, as well as of inscriptive
characters, which is inconsistent with the state of observed
facts.

Nothing is more peculiar in the excavated state of the ruins
than the mixture of dilapidation and repair which we observe
in the public buildings, obviously occasioned by an earth-
quake. I have already alluded to the account which Seneca
gives of the shocks experienced in a. d. 63. " Pompeios, ce-
lebrum Campanise urbem," says he " desedisse terrae motu
audivimus." And a httle after, " Herculanensis oppidi pars
ruit ; dubieque stant etiam quae relicta sunt -[•.■" At Pompeii
many pillars were found lying on the ground ; and it would
appear that the pubhc buildings were going to have been re-
stored in travertine instead of the tufa, with which they had

Lumifiden's Antiquities of Rome ; appendix oiji Herculaneum.
1[ Nat. Quopst. vl 11,

%^ Physical Notices of the Bay of Naples.

formerly been built. This remarkable coincidence of observed
facts with history is too strong to be overlooked.

It cannot, however, be concealed that the silence of his-
torians on the subject is very remarkable ; since, except in
Dion, we have no other direct testimony of the fall of these
cities ; but the declaration of Martial, in one of his epigrams,
certainly, as far as it goes, is perfectly satisfactory : —

" Haec Veneris sedes, Lacedemone gratior illi ;
Hie locus Herculeo nomine clarus erat :
Cuncta jacent fiaminis, et tristi mersa favilla.***

It has been alleged that Florus, who lived so late as the
reigns of Trajan and Adrian, has represented Herculaneum
and Pompeii as still existing, which certainly cannot be reason-
ably inferred from the passage in his history. He is engaged
in pointing out the causes of the war against the Samnites,
and takes the opportunity of launching out a little into the
praises of Campania, as if to give the reader, as is not unfre-
quent, a picture of the regions where the transactions of the
time were carried on (337 before Christ) in a sort of poe-
tical and impersonal style, without using any verb which shall
express either present time or past. He says, " Hie illi nobilis
portus, Caieta, Misenus, &c. Hie amicti vitibus montes Gau-
rus, &c. Urbes ad mare, Formiae, Cumae, Puteoli, Neapolis,
Herculaneum, Pompeii^ et ipsa caput urbium Capua, quondam
inter tres maximas, Roman, Carthaginemque numerata.""*
This mention of Capua, obviously referring to it in its pris-
tine state, and the remarkable want of any verb in the sen-
tence, inclines me to believe that I am not wrong in suppos-
ing that he refers to Herculaneum and Pompeii with ]<espect
to the time which his history describes ; when, in fact, they
were in their highest state of independence, not having been
subjected to the Roman yoke. Suetonius, in his History of
Titusj-f briefly mentions the eruption of Vesuvius in 79 ; but
describes the loss of life as so great as to make us believe that
some peculiar catastrophe, such as the destruction of a city,
must have occurred, though not particularly noticed in the

• Mart. Epig- iv. 44.

■f Florus, 1 16., and Chronol. in edit. var. Elz. 1674. t Cap. viii.

No. II. — Herculaneum, Pompeii, and Stabice. 123

passage, where the event is rather incidentally brought in as
an example of the Emperor^'s clemency than recorded as a fact
in history. The number of persons who perished was so great,
that Titus used his utmost endeavours to yield them relief;
and especially devoted the properties of such persons as had
no legal heirs preserved, to the aid of other survivors. This
intimates a calamity of great extent.

I have now discussed, (and I hope not unsatisfactorily,) all
the classical authorities which can throw light on this curious
subject. I must now shortly detail the facts regarding the
discovery and present condition of the cities, whose original
state and memorable catastrophe we have already considered.

It is remarkable enough that Herculaneum was discovered
at a depth of 68 feet below ground before Pompeii, which in
some places was but just covered with loose ashes. The for-
mer city was in fact brought to light by mere accident, which,
trifling as it is, is curious. In 1713, the Prince d'Elbeuf
from France, having married at Naples, resolved to settle in
the vicinity of Portici. He had with him a Frenchman, who
made statues for adorning his villa from a composition of
powdered marble, of which he got fragments from the country
people. The objects discovered by one man in digging a
well at his house were so remarkable as engaged the prince to
prosecute the excavation. The well, as it appears, came right
down upon the theatre ; and statues of Hercules and Cleopa-
tra were speedily discovered. The inscription on this theatre
was the following :

C.A.P.P.R.O.C.E.T.H.E.R.C.V.L.E.N.S.E.
S.D.D.

Which, I presume, may be thus interpreted :

CAPRE^ PROCHYTA ET HERCVLENSE (oppidum)
SIMVL DEDERVNT.

Whence it would appear that the theatre had not been the
property of the Herculanians alone, but built conjunctly with
the aid of the two islands now known by the names of Capri
and Procida. To detail the objects successively discovered in
this extraordinary city, would be quite beyond the scope of

194 Physical Notices of the Bay of' Naples.

this paper. Suffice it to say, that it appears to be more rich in
antiquities than Pompeii, probably from the greater haste
with which the inhabitants had been compelled to leave it.
In statues it is richest ; and here alone the papyrus rolls* were
found sufficiently dry and well preserved to afford any hope
in the task of unrolling them. Perhaps, too, it is from the
greater solidity of the covering strata that many of the more
perishable articles of curiosity have been preserved in great
numbers. The glass of windows,-|- as well as that used for
other purposes, paintings,^ styles, tablets, pens, fruit, honey-
combs, loaves, with the baker's name stamped upon them,
opera tickets, " honestae missiones," or the honourable dis-
charges of soldiers ; and all the innumerable objects of do-
mestic use and ornament, which render the museum at Naples
unparalleled in the world. The forum, and a temple of Jupiter
are the principal discoveries of this city, besides the theatre,
which is now the only place open for inspection, the rest hav-
ing been filled up with rubbish as the workmen proceeded,
from the difficulty of removing it from so great a depth below
ground. For many years the excavations have been discon-
tinued; but I understand that very lately they have been
partially revived by the Neapolitan government.

I consider it one of the most important objects of this paper
to make some remarks on the substance in which Herculaneum
is buried : curious, not merely in itself, but from the discus-
sion which it has excited, and the light which it is calculated
to throw on the geology of the volcanic formations. I have
already alluded to the want of a detailed examination of the
locality ; and I regret to think that I have little or nothing

* Very little has been done commensurate with the expectations formed
on the first surprising discovery of the papyri. A few Greek fragments
on rhetoric, music, and cookery are the only fruits of the labours of
Mazzochi, Rufini and de Jorio. Sir H. Davy himself could not succeed
in simplifying this tedious process.

t See a learned dissertation on the glass of the ancients in the Appendix
to Barihelemy's Italy ; also in the Philosophical Transactions, where may
be found many detached, but generally unimportant, notices on Hercu-
laneum.

% Ibid, and Eustace ; also Winkelmann.

No. II. — Ilerculaneum, Pompeii^ aiid Stabice. 125

to add in the way oi facts to what has already been published
on the subject.

During the last century it was usual to call the stony mat-
ter which envelopes this unfortunate city a lava. The word
is still occasionally employed, and, in the present want of defi-
nitive terms in the science, perhaps it would be difficult to ob-
ject to any particular designation which implies a volcanic pro-
duction. Yet certainly, according to the authorized use of
the term, it cannot be called a lava. In composition, it may
rather be supposed to fall under the head of tufa, volcanic
dust, or decomposed trachyte. As far as we are acquainted
with the constitution of the substance, it would seem improper
to place it along with the last rock, and I have always preferred
considering it as a tufa ; though, whether it flowed originally
liquid from the mountain, or in the state of ashes afterwards
consolidated by moisture, there has been much dispute. Delia
Torre, in his work on Vesuvius, seems not very decided on
this point, as the short casual notices of the subject which oc-
cur throughout his book are somewhat contradictory; but
from one very explicit statement,* I think he rather leant to
the idea, that a shower of volcanic matter fell, which was af-
terwards brought to a consistence by atmospheric moisture.
Sir William Hamilton gives a masterly sketch of his theory of
the origin of the Herculaneum tufa ; and, I am happy to say,
that it agrees perfectly with the results I myself deduced
from the examination of the spot, before I was biassed by
any theory on the subject, or had become acquainted with his
observations. The resemblance it bears to the tufas of Pausi-
lippo, and the vicinity of Naples, is too striking not to demand
an attentive consideration ; and I was speedily impressed with
the conviction, that their origin must have been extremely si-
milar. Every fact of appearance and structure corroborates
the idea, with this only exception, (as I humbly conceive,)
that the Kerculaneum tufa is more uniform in its structure,
and less broken into layers, so as to give us the idea of one

* " Si vede sopra le case di questa antica citta (Ercolano) un masso di
materia che non e se non che I'unione d'arena, cenere, lapilli e piettruzze
insieme uniti coll'acqua e divenute consistenti per Tumido continuo delle
acque piovane."^ — Storia del Fesuvio, 4to.

JS6 Physical Notices of the Bay of Naples.

simple and uniform action, the flow of a stream of liquefied
matter, (liquefied by water, not by heat,) while the various
and remarkable structure of the original tufas, in swelling ba-
sin-shaped stratifications, filled up with perfectly horizontal
layers, as I have often, with great satisfaction, contemplated
in the neighbourhood of Naples, leads me to attribute their
origin to the action of submarine volcanos. In the ancient
tufas. Sir William Hamilton describes various fossil remains
as being found, particularly oyster shells, which he has beau-
tifully illustrated in coloured plates of his Campi Phlegral*.
I am not aware whether such remains are, or are not, met
with in the tufa above Herculaneum ; but it is not of great
importance, for we are well assured that all volcanos hold a
particular communication with the sea, which would appear to
be a requisite agent in the production of their effects; for
they " seem in general to be situated near the sea-coast, and
rarely or never in the interior of large continents. Cotopaxi,
in South America, is perhaps of all volcanic mountains the
most distant from the ocean ; and yet it is only 140 miles from
the shores of the Pacific f." If I do not mistake, shells are occa-
sionally ejected from Vesuvius itself; and Humboldt assures us,
that in the Andes fish are frequently thrown from the craters
of volcanos. At all events, it appears strikingly probable,
that the substance which covered Herculaneum was ejected in
the form of liquid mud, being an accumulation of earthy,
pumiceous, and bituminous substances combined, and carried
along by the force of water and steam, probably at a red heat
"^hen issuing from the pressure it experienced in the bowels
of the mountain, which may probably have given rise, as I
have before hinted, to the description of the " latissimse
flammae," mentioned by Pliny ; since we know that no true lava

* Naples, Folio, 1776, Vol. ii. Plates xlii. and xlv. — It would be of the
highest interest to examine the nature of these fossil remains in the scale
of organization ; whether the oyster-shells approach nearer to the present
existing or fossil species, and if the vegetable remains are monocotyledonous
or dicotyledonous. To establish the relative antiquity of these tufas to
the other strata would be an acquisition of extraordinary interest in geo-
logy.

t Edin. Encyc, Art. Physical Geography, Vol. xvi. p. 487.

No. II. — Herculaneum, Pompeii, and Stabicc. 127

has flowed from the mountain within the Hmits of history be-
fore the year 1036. The heat of the Hqiiid mass is proved
by the carbonization of the timbers, corn, papyrus rolls, and
other vegetable substances which have been discovered ; and
that it dried from a fluid state is rendered in the highest de-
gree probable, from the remarkable appearance which may at
present be seen in one of the galleries excavated behind the
theatre, of an impression in the solid mass sharply left by a
mask which had been accidentally buried *. A similar illus-
tration is still preserved in the museum at Naples, where is a
piece of tufa containing a perfect cast of a portion of the hu-
man body. I have related a similar fact of the most recent
formation, the tufa of 1822, in the last number of these no-
tices -I* ; a specimen of which, in my possession, contains a
complete impression of a leaf of a tree, — a convincing proof of
the great liquidity of the substance.

Regarding the particular structure of the mass which covers
the city of Herculaneum, we may, in the first place, remark its
great thickness. Below Resina, the modern village, it is 125
palms (of about 11 inches each,) in depth, and above the thea-
tre, 85 French feet. Delia Torre informs us, that at the
deepest part it is divided by strata of white volcanic ashes, and
above the tufa there are 12 or 14 palms of common soil,
containing ancient tombs, and covered again by a modern,
true siliceous lava, (lava di pietra dura.) This, as far as I
know, is the most distinct statement of the strata above Her-
culaneum. The nature of the tufaceous substance is rather
peculiar. When first excavated, it is soft and easily worked,
but acquires a considerable degree of induration on exposure
to the air, though if it becomes nearly dry it is friable. In
structure it is porous, and contains a great number of imbed-
ded masses of various sizes, and decomposed mineral substan-
ces, (farinaceous leucites.?) but more particularly abundant
small black particles have been observed, J which appear to be

* This appearance existed as far back as the time of Sir William Hamil-
ton, who compares its sharpness to that of a cast in Paris plaster contract-
ed by cooling.

+ In No. xviii. p. 206.

t Delia Torre Storia del Vesuvio, § 119. Lalande, vii. 479.

128 Physical Notices cfthe Bmj of Naples.

of a bituminous nature, and contribute very much to unite the
whole into a compact mass. It burns on hot coals with no
smell of sulphur, but a cerulean flame. When thrown in
powder into hot water, a small quantity of aluminous matter
is dissolved.

From a combination of all the circumstances, T should be
disposed to believe, that the catastrophe by which Hercula-
neum was overwhelmed took place in the following manner.
I have elsewhere given it as my opinion, * that the alteration
in the point of ejection of the volcanic materials, which is ge-
nerally agreed to have taken place in the year 79, was owing
to a peculiar tendency of action towards the sea, by which the
wall of the crater of the Monte Somma was totally overthrown
in that direction, and its debris formed the plain from which
the present cone of Vesuvius rises. As it is also admitted
that no siliceous lava has flowed in the memory of man till
near 1000 years later, we suppose the vast basin of the origi-
nal crater filled with the materials fitted for the production of
an eruption of mud, — a phenomenon no less naturally to be
looked for from the action of the sea-water introduced into the
seat of volcanic agency, than established by decisive evidence,
more especially on the volcanos of South America. The fall
of the southern wall of the crater would bring the whole fiery
deluge in the direction of the sea, and, without doubt, the in-
terment of Herculaneum was only a portion of the ravages it
produced. During the time of this torrent flowing, which
probably took place from a lateral rupture, there is every rea-
son to believe that another mouth of the volcano ejected the
ashes which covered the country for so many miles, and which,
we have already seen, divided the mass of tufa into layers.

Brocchi, in his *' Suoh di Roma,'' -f in illustration of a par-
ticular theory of the production of tufas, alludes to Hercula-
neum, and the substances formed by modern volcanos. His
wish to generalize too much has led him beyond the limits of
probability. He says, that among the productions of modern
volcanos in full formation, although we have scoria, ashes, poz-

• See last Number, p. 193. T 8vo, Roraa, 1820. Page 194.

No. II. — Herculaneum, Pompeii, and Stahiae* 12t9

zolana, and lapilli, we never find tufa ; * and to get over the
difficulty which the example of Herculaneum affords, he adopts
a theory with which I am not acquainted, though I have be-
fore heard of the work by Lippi to which he alludes, and
which asserts the apparent paradox, that Herculaneum was
not destroyed by an eruption of Vesuvius, by a peculiar dilu-
vium. I am, however, decidedly of opinion, that the pheno-
mena we have considered are not at variance with the theory
of submarine volcanos, and that there is no necessity for such
far-fetched and problematical explanations of the interment of
Herculaneum.

The excavations of Pompeii and Stabij: demand less bX-
tention in a physical point of view than those at Herculaneum.
My remarks may be confined within a short compass. The
former was discovered in 1750, the latter about two years
sooner. A shower of true volcanic ashes was the cause of the
catastrophe ; and I need not repeat what I have already said
on this part of the subject. These ashes, it is to be remarked,
are essentially distinct from volcanic dust, which is nearly an
impalpable powder ; but the covering of Pompeii is composed
of real cinereous particles, vitrified, and harsh to the feel. The
lower strata approach in nature to white pumice, and the up-
per part is vegetable soil, in which vines grow. Even below
the buildings of Pompeii this vegetable mould is found, and
no less than three successive strata of black lava containing
leucites, which carry us back to the most remote antiquity.
The very houses of the town are a standing testimony to the
volcanic productions of primaeval times. The following are
reckoned among the building stones. 1. The old, dark, leu-
citic lava. % Reddish cellular lava, extremely porous. 3.
Gray and yellow volcanic tufa. 4 Calcareous tufa from the
river Sarno. -|- The depth of the shower of ashes varies con-
siderably. It is seldom, however, very great. There are

• '^ Tra i prodotti dei moderni Vulcani che ardono nei Continent! veg-
gonsi bensi, scorie, cenere, pozzulaiie, lapilli ; tufa non mai."

t Ferber's Travels j p. 152. I cannot help here remarking the extraor-
dinary want of information on the most important points, and the frequent
errors of this work, intended solely as a mineralogical tour through
Italy.

VOL, X, NO. I. JAN. 1829. I

130 Physical Notices of the Bay of Naples.

crystals of leucite intermixed, both fresh and farinaceous.
The labour of excavation is extremely small, yet the work
proceeds very slowly. It is impossible to imagine any-
thing more interesting than to watch the progress of the first
opening to day of the dwelling-houses concealed for 18 cen-
turies; to be yourself the first to tread the street where last
the Roman in his toga fled from the impending fate. Among
the last discoveries which in 1827 I saw, was a fountain deco-
rated with shells precisely in modern style, laid out in patterns
with great taste ; but the extraordinary thing is, that not a
shell appeared to be broken ; and the whole resembles strik-
ingly the fountains of the town of Naples. Very near it were
found moist olives in a square glass case, and caviare^ or roe
of the cod-fish, in a state of wonderful preservation ; an exami-
nation of these curious fresh condiments has been published
by Covelli of Naples. These are preserved hermetically seal-
ed in the museum there.

The public buildings of Pompeii bear the most perfect evi-
dence to the catastrophe of the earthquake under Nero. The
Temple of Isis has the following inscription : — " N. Popidius
N. F. Celsinus aedem Isidis, terrae motu collapsam a funda-
mento P. S. restituit. Hunc Decuriones ob liberalitatem cum
esset annorum Sex ordini suo gratis adlegerunt."" * A similar
inscription, not without interest, was discovered at Hercula-
neum, which I shall here insert, -f-

IMP. CAESAR. VESPASIANVS. AVG. PONTIF. MAX.

TRIE. POT. VII. IMP. XVII. P. P. COS. VII. DESIGN. VIII.

TEMPLVM. MATRIS. DEVM. TERRAE. MOTV. CONLAPSVM RESTITVIT.

I have already noticed the internal evidence which Pompeii
bears of this catastrophe in the overthrow of part of its public
edifices. From a large map of the Gulf of Naples, the dis-
tance of the nearest part of the walls of Pompeii to the sea ap-
pears to be almost a mile ; but we have perfect evidence that
the sea once washed its southern extremity. It is probable
that the course of the river Sarno is somewhat diverted to-
wards the east, since we have abundant reason to know that
the town was in the immediate vicinity of the river, so that
Cluverius placed its site about two miles too far east, at Sca-
fati. These changes are therefore owing to the ejected mat-

• Swinburne and Lalande. t Phil Trans. 1758. Vol. L. p. 619'

No. II. — Herculaneum, Pompeii, and Stabice. 131

ter of the volcano, simply in the form of ashes, and inde-
pendent of eruptions of mud or lava. It may, however, have
accumulated to its present extent on different occasions, as,
for instance, we find that in the eruption of 1822 the ashes
lay three feet deep in Pompeii, whose ruined walls were
threatened by a second catastrophe; and the whole has since
. been cleared of the new deposit.

The excavations of Stabiae, which afforded little of interest
except lachrymatory vases and papyrus rolls, have long since
been filled up, so that the curious traveller can gain no infor-
mation by visiting its site. I shall therefore quote a passage
from Swinburne's Travels, written about fifty years since, which
gives a perspicuous view of the true state of that small town,
of the nature of its interment, and throws light upon its origi-
nal condition, which we have seen has been a matter of some
debate. " March 26th, 1776. — Having received an invitation
to be present at the opening of some lately discovered rooms at
Stabia, I went thither with a party. On our way we visited
Herculaneum and Pompeii. We then traversed the rich plain
that lies between Vesuvius and the Sorrentine branch of the
Apennines, and came by a gentle ascent to the excavations.
Stabia was a long string of country houses rather than a town,
for it had been destroyed by Sylla, and before the reign of
Titus all its rebuilt edifices were . overturned by an earth-
quake. In the catastrophe of 79, the wind blowing furiously
from the north, brought the ashes of Vesuvius upon it. All
the country was covered with cinders and lapilli, or small
pumice-stones, many yards deep. Stabia, though six miles
from the mountain, was overwhelmed and lost, till it was
casually discovered about twenty-eight years ago. The earth-
quake had so damaged the buildings that none of them can
be preserved, and therefore, as soon as every thing curious is
taken out, the pits are filled up again. The ashes penetrated
into all parts, and consumed every thing that was combustible.
On our arrival the workmen began to break into the subterra-
W nean rooms, and, as the soil is all a crumbling cinder, very little
labour was requisite to clear them. When opened, the apart-
ments presented us with shattered walls, daubed rather than
painted with gaudy colours in compartments, and some birds

132 Physical Notices of the Bay of Naples.

and animals in the cornices, but in a coarse style, as indeed
are all the paintings of Stabia. In a corner we found the
brass hinges and locks of a trunk ; near them part of the con-
tents, viz. ivory flutes in pieces, some coins, brass rings, scales,
steelyards, and a very elegant silver statue of Bacchus, about
two inches high, represented with a crown of vine-leaves, bus-
kins, and the horn of plenty." *

In this description we may remark, that the extremely shat-
tered state of the walls here mentioned, could not have been
the consequence of the earthquake of a. d. 63, otherwise the
houses could not have been sixteen years after in the habitable
state which the utensils and papyri buried among the volcanic
ashes prove them to have been. We must, therefore, ascribe
it to the tremendous earthquake described by Pliny, as ac-
companying the eruption. If it be asked why the walls of
Herculaneum and Pompeii are not in the same condition, (for
in general they are sufficiently secure) we may reply, that this
circumstance, so instrumental to the marvellous preservation of
these two cities, is owing to their situation upon a porous and
ill-compacted foundation, which deadened the terrestrial vibra-
tions ; while Stabiae, seated on firm rock of a branch of the
Apennines, niust necessarily have experienced the shock in
a far more powerful degree. The testimony of this extract
has formerly been alluded to in support of my opinion of the
pre-existent condition of Stabiae. From it we distinctly gather
that the eruption of Vesuvius was the decisive cause of its de-
struction,— a position which we have seen Breislak and others
deny, — and thatit appears to have existed rather as avillage than
a town, with which the inferiority of its paintings agrees. The
description of Swinburne, on the whole, is to be considered a
valuable one, as supplying a link in the history of the Buried
Cities, which, in the sources I have consulted, is generally
awanting.

I have now completed the sketch I proposed of the present sub-
ject, and perhaps I have filled it up with as much minuteness
as most of my readers would be disposed to follow me through.
I am not aware of having omitted any material fact which has
come to ray knowledge, relating to the Physical History of Her-
* Swinburne, vol. i. p. 127 — 129.

Postscript to No. I. — Account of Mount Vesuvius. 1B3

culaneum, Pompeii, or Stabiae. Iil an antiquarian point of view,
I have done little in this paper ; but the title I have adopted
for these outlines of " Physical Notices" warns me not to de-
part too far from the object proposed. i
In the preceding pages, we have considered the primitive
condition of the once flourishing cities of Campania. We drew
from ancient sources and combined information regarding their
size, situation, and antiquity, more especially as regarded their
rediscovery. We contemplated the circumstances of the event
by which they were destroyed, and, with the calm abstraction
which the lapse of near 2000 years has afforded, we attempted
to trace the facts deducible from the glowing description hand-
ed down to us by an eye-witness of the catastrophe. We pas-
sed over the lengthened period of their awful repose amidst the
ruins of nature, and only paused to notice the conflicting
opinions of antiquaries after the revival of letters, regarding
the site and history of those towns, over which time as well
as nature had thrown her veil ; and we resumed the thread of
the inquiry, when circumstances brought to light these stupen-
dous monuments of antiquity, preserved to the eyes of later
generations almost miraculously, by a cause which in the course
of time may never again produce a parallel event ; which
opened a mine of exhaustless wealth to all who profess any
regard for the history of art, of the human race, or of the hu-
man mind. " This scene of a city," says the elegant Eustace,
*' raised from the grave where it had lain forgotten during the
long night of eighteen centuries, when once beheld, must re-
main for ever pictured on the imagination ; and whenever it pre-
sents itself to the fancy, it comes like the recollection of an
awful apparition, accompanied by thoughts and emotions so-
lemn and melancholy !" A

Postscript to No. I. of these Notices — on Mount Vesuvius,

Since the publication of my paper on Mount Vesuvius, I
have consulted Humboldt's small work, entitled " Tableaux
de la Nature,'"' ]ust published at Paris, which contains a paper
on the structure and action of volcanos, part of which is es-
pecially directed to Mount Vesuvius ; and I shall here subjoin

134 Physical Notices of the Bay of Naples.

one or two remarks connected with that work which maybe con-
sidered as a postscript to my last paper. The extreme N. W. ,
point of the crater, which received the name of " Rocca Del
Palo," from a post which stood upon it, remained, it would
seem, unaffected by the internal action of the mountain, at least
from 1773 to 1822. This Humboldt points out as an interest-
ing proof that some positions of considerable stability may be
found even in a volcano whose aspect is apparently so change-
ful as Vesuvius. Saussure's measurement in 1773, which I
gave in last Number, p. 193, was nearly the same as all suc-
ceeding ones ; but the same observer remarked that the N. W.
and S. E. edges of the crater were precisely equal in that year,
but in the eruption of 1794 the latter was lowered 75 toises.
What the changes of this discrepancy may be is doubtful ;
for we have in this instance an example of a general haste
and want of attention, which is rather conspicuous in this little
essay of Humboldt's, and which gives us room to doubt his accu-
racy on the measurements of the crater, which are much smal-
ler than those I have given in my paper. He says, the bottom
of the crater after the eruption of 1822 was 750 feet below
the northern, and 200 below the southern edge. This leaves
550 feet for the difference. Yet he tells us, " d'apres mes der-
nieres observations le bord du S. E. que en 1794 etait de 400
pieds plus bas que le precedent (le N. W.) a eprouve un dimi-
nution de 10 toises." Hence for the difference we would have
400 feet +10 toises = 460 feet instead of 550. I point this
out as one of the inconsistencies which occur in this paper.
No one I should conceive, who has seen the crater in its present
state, could take it on any man's word, that the bottom of the
crater is only half as deep below its lowest edge as that is be-
low the highest : and I can more distinctly express my con-
viction, as in 1826 I descended two-thirds of the depth to the
bottom from the lowest edge. Besides, the numbers I have
given in my last paper, chiefly derived from information on
the spot from my most intelligent guide, have been corroborat-
ed from very different quarters ; the general dimensions, by
Ferrar?s " Guida di Napoli,^'' and a statement which appeared'
in the Edin. Phil. Journ, vol. x. : the total height, by Lord
Minto's measurements ; and the difference which I heard ex-

Postscript to No I. Account of Mount Vesuvius. 125

isted between the higher and lower edges of the crater (500
feet) by Humboldt's own account. From the general accu-
racy of the statements, and the evidence of my own senses, I
am disposed to maintain, in great part at least, the numbers I
have already given.

Another inconsistency which I at first believed existed in
Humboldt''s paper, that of stating the proportion of the cone
of ashes to the total height as one to tefi, instead of one to three,
in contradiction to his own personal narrative, (See last Num-
ber, p. 1 96,) I found to arise from an erroneous translation given
in a contemporary journal, which, in presenting this paper to
the English reader, has omitted, I think, the most valuable
part of it, — the statements of heights of the various portions of
the mountain at different times, with which, I think, the reader
will thank me for presenting him, as I consider them extreme-
ly valuable.

A. Rocca del Palo. Highest N. W. summit above the sea.

Toises.

Saussure, 1773, barometric measurement, - 609

Poh, 1794^, ditto. - - - 606

Breislak, 1794, ditto. - - - 613

Gay-Lussac, De Buch, and Humboldt, 1805, ditto. 603

Brioschi, 1810, trigonometric measurement, - 638 .

Visinti, 1816, ditto, - - , - 622

Lord Minto, 1822, barometer, - - - 621 .

P. Scrope, 1822, ditto, (slightly uncertain) - 604

Monticelli and Covelli, 1822, - - - 624

Humboldt, 1822, - - - - 629

Probable result, 625 toises above the sea, 317 above the
hermitage.

B. Lowest edge of the crater, (S. E.)
1794, - - - - 559

Gay-Lussac, De Buch, and Humboldt, 1805, - 554
Humboldt, 1822, - - - - 546

C. Height of the cone of Scoriae in the crater 1822,

above the level of the sea. Lord Minto, (barometer) 650

Brioschi, (various trigonometric operations) - 636

or, - - 641

136 Physical Notices of the Bay of Naples.

Toises.

Probable true height, - - - . 645

D* Puilta Nasone. Highest part of the Somma.
Shuckburgh, 1794, barometer, - - - 584

Humboldt, 1822, ditto, - - - . 586

E. Valley of the Atrio del Cavallo.
Humboldt, 1822, - - r. . - 403

F. Foot of the cone of ashes.
Gay-Lussac, De Buch, and Humboldt, 1805, - 370
Humboldt, 1822, - ... 388

G. Hermitage of St Salvador.
Gay-Lussac, De Buch, and Humboldt, 1805, - 300
Lord Minto, 1822, . - . . 308.9
Humboldt, 1822, - - 307.7

Humboldt has no doubt that, in the period 1816-22, the
height of the Rocca del Palo had been about 12 toises higher
than during the period 1773-1805, which he considers a sin-
gular proof of gradual internal elevation. The points A, D,
and E, correspond respectively to C^ A, and B, of my section
of Vesuvius in last Number. The continuation of these im-
portant observations cannot fail to be of the greatest interest.
Humboldt mentions the statement I noticed (No. xviii. p. 206)
of gold existing in the volcanic dust, and states, that the re-
cent experiments of the best chemists disprove the assertion.
I have learned, that, since the slight eruption of March this
year, Vesuvius has been in a state of great agitation during
the summer ; but particulars have not reached me. I hope the
length of this note will be excused, as the facts it notices are
of great importance in surveying the phenomena of Vesu-
vius.

A .

Mr Kenwood's account of Steam-Engines. 13T

Art. XVIII. — Notice of the performance of Steam-Engines
in Cornwall for June, July, August, and September 1828.
Communicated by W. J. He^Twood, Esq. F. G. S.

Reciprocating Engines drawing Water.

Mines.

« -a

Length of
Q stroke in cy-
linder.

ii|
III

10,1

^ No. of strokes
•^ per minute.

1 Millions of lbs-

weight lifted 1
foot high by the
consumption of
1 bush, of coal.

Huel To wan.

78,8

10,

4,89

3,4

56,3,

Cardrew Downs,

8,75

10,1

6,4

58,

Huel Hope,

9,9

5,8

70,7

Huel Vor,

63*

7,25

5,75

17,5

5,4

24,8

7,5

19,58

5,9

41,9

7,9

4,8

30,7

10,

7,5

14,8

57,2

6,75

5,5

13,6

6,1

49,9

Poladras Downs,

10,

7,5

8,63

6,3

48,4

Huel Reeth, -

7,5

15,29

8,1

25,5

Balnoon,

3,1

17,4

Huel Penwith, -

8,75

7,9

22,6

United Hills, -

8,25

6,68

4,1

34,7^

Great St George,

10,333 6,5

9,4

5,6

31,1

Perran Mines, -

6,75

9,1

7,2

23,

Crinnis Mines, -

8,25

11,5

4,7

33,4

6,75

9,9

4,1

26,9

Stray Park,

7,75

5,25

7,5

4,4

31,6

Huel Penrose, -

8,5

6,6

9,8

6,9

32,7

Carzise,

8,5

7,34

4,6

34,

Huel Caroline,

- 30

26,

10,3

35,2

Huel Trevoole,

- 30

21,25

7,2

41,7

St Ives Consols,

14,3

6,8

33,2

Lelant Consols,

- 15

7,5

4,5

16,1

2,7

11,9

Huel Damsel,

. 42 1 7,5

5,75

21,5

6,8

37,9

8,2

2,8

27,6

Ting Tang,

7,75

6,75

14,2

7,5

44,3

138 Mr Kenwood's aaoww^ of Steam-Engines.

Reciprocating Engines drawing Water.

Mines.

58 1 7,75

Length of
Ci stroke in the
pump.

15,47

° S
6 *^

Millions of lbs.
weight lifted 1
foot high by the
consumption of
1 bush, of coal.

Treskerby,

38,3

Huel Chance, -

45 1 7,918

19,7

5,2

27,8

Huel Rose,

18,

7,8

32,6

Huel Fortune, -

10,2

7,9

36,5

If uel Beauchamp,

7,75

12,3

4,2

30,8

East Huel Unity,

8,75

6,75

7,97

4,7

22,9

Great Work, -

8,9

6,9

40,6

Dolcoath,

7,5

11,9

5,4

37,4

Huel Tolgus, -

10,

7,5

3,7

48,8

Tresavean,

5,5

4,1

23,1

Huel Busy, -

10,

7,5

11,4

6,9

51,2

North Downs, -

9,83

7,75

7,9

5,1

39,6

Huel Harmony,

9,35

29,

Huel Montague,

8,1

6,1

28,1

East Crinnis,

5,5

8,57

4,7

22,9

10,

5,9

36,4

Pembroke,

9,75

7,25

11,27

4,3

47,1

6,5

6,1

24,3

Huel Unity, -

5,5

14,4

5,7

26,9

Poldice,

10,

11,5

51,2

9,5

6,^5

11,9

6,8

32,1

United Mines, -

7,9

5,2

36,2

7,5

12,9'

8,3

34,1

Consolidated Mines, 90

10,

7,5

8,12

6,5

54,6

10,

7,6

7,4

44,6

7,75

6,5

17,7

4,2

37,7

10,

7,5

7,83

62,9

10,

7,5

10,6

4,1

31,6

10,

7,5

8,8

4,7

56,1

Binner Downs,

7,5

11,8

6,9

48,5

7,5

7,87

9,1

35,9

10,

7,5

10,93

8,1

62,9

M. Gersu-d's Meteorological Register for Kotgurli. 139

Average duty 38.2 millions of lbs. lifted a foot high by the
consumption of each bushel of coal.

Watt''s (double) rotatory engines working machines for
bruising tin ores at

HuelVor, 24 6. 6. 12. 16.8 18.2

27 5. 5. 12.5 18.2 21.5 .

16.5 5. 5. 8.5 25.8 14.3

Average duty of rotatory (double) engines, 1 8 millions.

* Engines thus distinguished are Watt's double.

•f Those thus noted receive the steam first into a high pres-
sure cylinder, whence it passes to a Watt's single engine, the
pistons of both cyhnders being connected with the same lever.

All the others in the preceding list are Watt's single en-
gines.

Art. XIX. — Abstract of a Meteorological Register kept at
Rampoor and Kotgurh, in January, February, and March
1822. By Captain Patrick Gerard, of the Bengal Na-
tive Infantry. Communicated by the Author.

The observations from which the following general results
are deduced were made at Rampoor and Kotgurh.

Rampoor is situated fourteen English miles north east of
Kotgurh, and 3398 feet above the level of the sea.

Kotgurh is situated in north latitude 31° 19', and east
long. 77° 30', at the height of 6634 feet above the sea.

All the barometrical observations were made at Kotgurh,
and the thermometrical ones were made between January 18th,
and 31st, inclusive, and between February 10th and March
31st. The observations at Rampoor were only those with the
thermometer and on the weather, and were made on the first
17 days of January, and the first 9 days of February.

January 1822.
Barometer.— Max. 23.700. Jan. 23; wind E.— Min. 23.520,
Jan. 28 ; wind W.
Range of mercury, .180,
Mean of observations, 23.624.

140 Mr Gerard's Meterological Register Jbr Kotgurh,

Thermometer.— Max. 70°.8, Jan. 16 ; wind N. N. E.— Min.
30°, Jan. 28 ; wind E.
Range 40°. 8.

Mean temp, of external air for the month, 48°.7
Number of days clear. - - - - 12

Fair, but cloudy, partially cloudy, and

overcast, - - - - 11

Rain and snow, - . . 8

Thunder, - - - - twice.

February 1822.

Barometer.— Max. 23.760, Feb. 28; wind W.N.W

Min. 23.330, Feb. 16; wind E.
Range of mercury, 430.
Mean of observations, 23.590.
Thermometer.— Max. 61°.2, Feb. 6; wind S.S.W.— Min. 30° 4,
Feb. 24 ; wind W.
Mean temp, of external air for the month, 41°.6
Range 30.8°.
Number of days clear, - - - _ 5

Fair, but cloudy and partially cloudy, 12
Rain, snow, and hail, - - 11

Thunder. - - . _ 0

March 1822.

Barometer.— Max. 23.840, Mar. 20; wind W.— Min.
23.400, Mar. 23 ; wind E.
Range of mercury, 440,
Mean of observations, 23.661.
Thermometer.— Max. 69°.7, Mar. 21 ; wind W.— Min. 37°,
Mar. 1 ; wind E.N.E., and Mar. 14; wind E.
Mean temp, of external air for the month, 50. 1°.
Range 32.7°.
Number of days clear - _ _ . 7

Fair, but cloudy, partially cloudy, and

overcast, - - - - 12

Rain, - - - - 12

Thunder, - . . 4 times.

Account of the Rain which falls at Bombay. 141

General Results for the three

MONTHS.

Inch.

Mean height of barometer,

23.625

Maximum, . . - -

23.840

Minimum, _ , -

23.330

Mean height of thermometer.

46.°8

Maximum, - - - -

70.8

Minimum, - -

Range, . .

40.8

Art. XX. — Account of the Rain which fell at Bombay in
June^ July, August, September, and October, from J 817 to
1827. Communicated by Alexander Adie, Esq. F. R. S.
Edin.

As it is of great importance to determine the relation which
subsists between the quantity of rain which falls annually at any
given place, and its mean temperature, the following very va-
luable results, which have been communicated to us by Mr
Adie, will be considered by the meteorologist as of great interest.
From the observations being confined only to five months
in each year, we presume that little rain falls during the other
seven months, and that the mean results may therefore be
regarded as giving nearly the annual quantity of rain which
falls at Bombay.

June.

July.

August.

Inches.

1817

45,72

23,67

9,34

1818

22,54

17,69

28,45

1819

15,95

30,66

20,24

18^0

18,82

28,37

19,49

1821

15,18

20,60

28,52

1822

29,21

26,59

33,83

1823

21,76

15,96

19,70

1824

3,89

8,07

17,86

1825

24,45

25,17

12,94

1826

17,75

26,97

8,40

1827

49,15

10,29

10,51

142 Account of the Rain xvhich Jails at Bombay.

September,

October.

Total in all the
five months.

Inches.

1817

24,87

0,19

103,79

1818

10,39

2,07

81,14

1819

10,11

0,14

77,10

1820

10,66

77,34

1821

18,29

0,40

82,99

1822

22,16

0,82

112,61

1823

4,28

61,70

1824

1,78

2,37

34,33

1825

9,68

72,24

1826

23,50

1,23

77,85

1827

10,16

0,92

81,03

Mean of eleven years,

78,34

It appears from the detailed register of the pluviometer for
1827, which accompanied these monthly and annual results,
that rain fell every day from the ^th June to the 9>0th Septern^
her, with the exception only of 4 days, viz. June 11th and
31st, and July 1st and 27th. In 1827, the principal showers
fell in June ; the most remarkable of which were as follows :

Inches.

June 1 3,

7,00

June 19,

3,80

15,

3,18

20,

4,04

16,

5,17

24,

2,21

17,

2,10

25,

3,95

18,

3,36

28,

5,92

In the able article on Hygrometry in the Edinburgh
Encyclopedia, vol. xi. p. 597, and in the article Physical
Geography, vol. xvi. p. 514, Dr Anderson of Perth, by
whom these articles were written, has explained an ingenious
process for determining the quantity of rain which falls in dif-
ferent latitudes from the equator to the pole ; and has given
the following table for every five degrees of latitude :

Account of the Rain which falls at Bombay. 143

Latitude.

Inches.

0°

73,17

71,S9

68,72

64,47

59,11

53,12

46,77

40,50

34,92

29,79

Latitude.

Inches.

50°

25,36

21,72

18,69

16,32

14,49

13,16

12,24

11,72

11,55

In consequence of Dr Anderson having used, in the con-
struction of this table, Tobias Mayer^s law of mean tempera-
ture, which gives

For the equator,
For the pole,

Instead of

For the equator,
For the coldest point.

85° Fahr.
31<^

81 J° Fahr.

-3|°

the results in the table are necessarily incorrect. But even
if we recompute it according to the most approved law of tem-
perature, it does not afford even approximate results.

At the equator, for example, the annual fall of rain should,
in the corrected table, be 64 J inches ; whereas at Bombay, in 18°
of latitude, it is as high as 78 inches. In the east of Scotland,
in latitude 55° — 57°, the annual fall of rain, as deduced from
a most extensive series of accurate observations, is 26 inches ;
whereas at Paris, in latitude 48°, the annual fall of rain on
an average of 20 years is scarcely 20 inches ; where, accord-
ing to the table, it should have been much greater than in
Scotland. We shall return again to this subject in an early
number.

144 Mr Weston's Experitnents on Bottles immersed

Art. XXI. — Experiments on the penetration of water into
Bottles immersed to a great depth in the sea^ made in a Voy-
age from India to England. By Charles H. Weston,
Esq. In a Letter to the Editor.

Sir, London^ 6th October 1828.

Under the article " General Science"" in your last Quarterly
Journal, you detailed some experiments made by Dr J. Green,
which tended to prove that glass- vessels were impervious to
water, although submitted to very considerable pressure. As
T had during my voyage from India to England directed my
attention to the same subject, I am induced to state to you a
few of my experiments, which, although insignificant and un-
satisfactory in themselves, do, when viewed in connection with
those of Dr Green, afford a collateral proof of the justness of
his conclusions.

The bottles made use of were of white flint-glass with
ground glass-stoppers, round which, at the point of contact
with the bottle, a quantity of putty was placed, and, embracing
both lute and stopper, some linen was fastened, which prevent-
ed a removal of the lute during the descent of the bottle-
This I found a simple but effectual mode of rendering bottles
water tight, as the putty, independent of its oily nature, suffers
a very considerable condensation by the pressure of the super-
incumbent water.

Some bottles were lowered to twenty fathoms, drawn up
and examined, and again lowered an additional ten fathoms,
and so on. Others were attached to the line at different dis-
tances, and four or five bottles were thus at the same time sub-
mitted to various degrees of pressure.

It will be necessary to detail the fate of a few bottles only.

Two bottles were sent to thirty fathoms depth, inclosed in
a fine netting to receive the pieces in case of fracture. They
were not only destroyed, but the minute state of division ot a
great part of the glass was such as to give one the idea of its
having been literally pounded.

Hollow glass-stoppers were most used, and, as they were
beyond all suspicion hermetically closed, they were submitted

to a great depth in the Sea. 145

to every degree of pressure. Several were destroyed, but one
at thirty fathoms and another at eighty fathoms formed cu-
rious exceptions. They were cracked and half-filled with water,
but the water was effectually inclosed within them. Those that
came up entire contained not the least water.

Two very strong bottles were then sent down, one to 140
fathoms, which came up quite empty, and the other to 120 fa-
thoms. This last admitted half a teaspoonful of water, but this
was between the stopper, as the same bottle, fresh secured, and
sent to the increased depth of 140 fathoms, came up unaflPected.
This last bottle, containing sixty-five square inches of surface,
must have suffered a pressure of at least ten tons.

Now, as under every circumstance and under every pressure
(for mention is not made of half the number submitted to trial)
the glass vessels were either broken or cracked, or had receiv-
ed nothing, it is fair to conclude with Dr Green that glass is
impermeable.

I would also remark, that the case of the hollow glass stop-
pers exhibits a singular proof of the great elasticity of glass ;
for they had under strong pressure admitted water through
those cracks, which so collapsed when that pressure was re-
moved as completely to retain that water.

The cracked stoppers also, as they were but half filled, are
incontestable evidence of the manner in which bottles generally
are broken, not by being first filled, and then suffering from
the expansion of water when under less pressure, as Dr Green
seems to think, but by actual pressure from without.

I might here subjoin that a soldered tin canister, as being
well calculated from its flexibility to show the manner in which
vessels were affected, was lowered to 100 fathoms. It was bul-
ged in and most severely compressed.

I have the honour to be. Sir, your most obedient servant,

Charles H. Weston.

To Dr Brewster, F. R. S. &c. &c.

VOL. X. NO. I. JAN. 1829. K

146 Mr Harvey on a Luminous Arch seen at Plymouth.

Art. XXII. — On a splendid Luminous Arch seen at Plymouth,
Sept. 29, 1828. By George Harvey, Esq. F. R. S. Lond.
and Edin.j F. L. S., F. G. S., &c. &c. Communicated by the
Author.

At 10 minutes after 8 p. m. on the day above mentioned, a
column of white light, about 20"" above the horizon, 20° long,
and about 1° wide, was perceived in the W. S. W. quarter of
the heavens. The appearance was unusual, but still not such
as to arrest particularly the attention. After an interval of 5
minutes, its extent had very much increased, appearing with
extraordinary splendour between a Lyrae and a Aquilae, and
crossing the meridian about 10° to the south of a Cygni, its
breadth at the same time being doubled. Hastening to higher
ground, to command more completely the beautiful pheno-
menon, it was found, at 27 minutes after 8, to extend across the
heavens, passing nearly midway between /3 and y Andromedae,
covering with its pure and delicate light the Pleiades, and de-
spending nearly to the eastern side of the horizon. During the
changes, the western portion of the arch increased also in
length, descending to within 10° of the horizon, where it was
obscured by clouds ; and at the same time, it was observed to
undergo a remarkable inflexion towards the north, at about the
elevation of /3 Ophiuchi, over which star it passed.

.^h^ whole arch now presented one magnificent zone of clear,
white, silvery light, of about 4° wide, having its edges parallel,
and beautifuUy^ defined. Its general direction, independently
of tlie iufles;io^, was nparly in the plane of the dipping-needle;
and but for that inflexion, its two extremities would have been
in a line at right angles nearly to the magnetic meridian.

The brightness of the arch was by far the greatest at its
western extremity, the light progressively diminishing to its
eastern end. The light also was steady, presenting no corus-
cations, excepting at about 20 minutes before 9, when a
trembling about the Pleiades was perceptible, the arch in that
region appearing to separate into somewhat indistinct laminae,
from north to south, at inclinations of about 40°.

As the growth of the arch from west to east, was accompa-

Mr Harvey oti a Luminous Arch seen atPlymouth. 147

nied by a progressive increase of its splendour in the same di-
rection, so the gentle diminution of its light was, by the same
gradual steps, in the opposite direction, from east to west. At
25 minutes before 9, no traces of it could be perceived in the
east, and the Pleiades glittered with their primitive lustre. At
10 minutes before 9, a faint portion of its extremity could
be seen in the constellation Andromeda ; and at 5 minutes be-
fore 9, the last traces of it were perceptible in the wing of
Cygnus. The clouds that had lingered in the west now began
to rise ; and at 20 minutes after 9, only a small portion of
it Could be seen in the west, at about an elevation of 30°. At
half past 9, the whole sky was hid in a mass of vapour, and all
traces of the splendid phenomenon lost.

From 20 minutes after 8, till the general shrouding of the
whole hemisphere in vapour, the entire quadrant of the Hea-
vens, from the north to the western points of the horizon, Was
illuminated by a strong light, bearing a close resemblance to
the clear and beautiful twihght which has sometimes announ-
ced the approach of the sun, on those very fine mornings in
summer which I have dedicated to the interesting subject of
dew.

■ During the coiitinuance of this beautiful phenomenon, the
Milky Way shone with extraordinary brightness, and seemed
to derive new splendour from it.

During the time these interesting observations were made,
I was accompanied by my intelligent young friend, Mr Richard
Rawle, who called my attention to the light existing between
the north and western points of the horizon ; and I have been
favoured by my gallant friend. Captain Rotheram, R. N., with
the following extract from his valuable meteorological register.

Barom. Temp, at Temp, at Rain. Wind,

m A, M. 10 p. M.

Sept. 28, 29.90 64° 58" 0.100 N. W.andW.

29, 29.95 62 57 0.066 W.

30, 29.85 63 57 0.050 W.

Pi^YMouTH, October 1, 1828.

148 Mr Harvey on an ifiteresting Meteor ologieal Phenomenon.

Art.. XXI II— On an interesting Meteoi'ologkal Phenomenon.
By George Harvey, Esq. F. R. S. Lond. and Edin. Mem-
ber of the Royal Geological Society of Cornwall, &c. &c.
Communicated by the Author.

X HE formation of a cloud of the cirro-cumulus kind, at the
extremity of a cape or headland, rolling forward from a point
of origin successive masses of dense and visible vapour, so as
to create the appearance of an interminable moving cloud, has
no doubt often attracted the attention of your meteorological
readers ; but as peculiar localities sometimes occasion diversi-
ties of appearance worthy of being recorded, I have forwarded
for your inspection the inclosed sketch. (Plate I. Fig. 4.)

The entrance of Plymouth Sound is situated between two
moderately elevated portions of land, that to the right of the
drawing in the distance being Penleepoint, and the nearer land,
covered with beautiful groves. Mount Edgecumbe ; the land on
the left or eastern side being Staddon Heights ; the dark line
in the sea between the hills representing that great monument
of skill, the Plymouth breakwater. About noon, on the 11th
May, a cirro-cumulus, of a very dense and definite character,
was perceived to come from the verge of the western horizon
with a moderate velocity, and after passing at a small elevation
above the woody summit of Mount Edgecumbe, vanished in
the pure and cloudless air over the tower on the distant pro-
montory of Penlee. The moving mass formed a continuous
cloud, accommodating itself to all the changes and inequalities
of the land. Over the sea, however, not a cloud was to be
seen ; but on the eastern side, nearly over the flag-staff, the
cloud was perceived to form again, and with a steady and uni-
form velocity to roll its volumes at nearly the same elevation
above the land, until it was again lost in the farthest verge of
the eastern sky. From the west, therefore, there continued
incessantly to come forth large and visible volumes of cloud,
which became dissolved in the air just where the sea began to
exercise its influence upon them ; and where the water lost
its power, just above the flag- staff, the vapour became again
condensed, so that over the sea, between the well-defined ex-

Mr Harvey 071 an interesting Meteorological Phenomenon. 149

tremities of the clouds, a pure and cloudless sky prevailed,
whilst over the land, on both sides, the moving masses conti-
nued their courses for upwards of two hours.

It was most interesting to watch the gradual progress of the
cloud on the western side ; how steadily it advanced with the
gentle south-west wind; how it maintained its character andform
up to a particular point ; and how soon it became mingled with
the brilliant expanse of the sky when the temperature of the
sea began to exercise its power.

Now and then a denser portion of the moving column would
detach itself just before it reached the tower, and, passing on
with the breeze, seemed to maintain an ineffectual struggle
with the influence of the water below ; but gradually losing its
dimensions and form, would at last vanish like the mass from
which it had been separated. /

Mount Edgecumbe has often its natural beauties very much
increased by the most varied and interesting formations of mist.
About a month ago, a sudden alteration of temperature pro-
duced a condensation of moisture, attended with the most
striking appearances. The higher parts of the mount became
rapidly covered with masses of mist, having a remarkable uni-
formity in their superior limits, but dropping in their lower
extremities, in the most various and beautiful forms. The
process of condensation commenced, as in the former example,
at the extremity of the hill ; and as the gentle S. E. breeze
carried forward the rolling volumes of visible vapour, the in-
equalities of the land, and the groves with which that charm-
ing spot abounds, occasioned innumerable alterations of figure ;
— this moment falling in graceful festoons between the oaks
and the cedars, which wave in majesty and beauty; and at the
next, rising suddenly above the pines and the elms, losing it-
self gradually in the cloudless azure above. For two hours
and a half this very interesting appearance continued, displaying
every variety of light and shade, and endless groups of the
most fanciful and lovely forms. Now and then also, tinges of
red, and yellow, and gray, falling on different points of the
misty forms, increased in a high degree the beauty of the
scene. *

* In April 1819, a period never to be forgotten by the writer of this brief

IfiO M. Berthier's Description of Nontrcmite.

Ou this occasion, the hill on the opposite side exercised no
visible influence on the volumes of air which passed over it,
presenting in this respect as striking a contrast to Mount
Edgecumbe as its bleak and " wind-swept crest" does to the
noble slopes and thick clustering of her " favoured sister hill.""

Plymouth, October 1, 1828.

Art. XXIV. — Description of Nontronite, a new Mineral dis^
covered in the Department of the Dordogne.*^ By M. P.
Berth [ER.

iHE arrondissenoent of Nontron, which occupies the northern
part of the department of the Dordogne, possesses an impor-
tant stratum of manganese ore. This ore is known in com-
merce under the name of the manganese of Perigueux, It has
been wrought very languidly for a long time, but the con-
sumption of manganese having of late years considerably in-
creased, the works have been carried on with more spirit, and

notice, the amiable and lamented Mr Dugald Stewart visited this charm-
ing place, and remarked, after contemplating its innumerable beauties,
" tliat it had furnished him with materials for enjoyment for the remain-
der of his life." A native poet, Mr Carrington, a man whose splendid ta-
lents, and fich and exuberant genius deserve a better fate, says in his beau-
tiful poem, " the Banks of Hamar"

'Tis not local prejudice that prompts

The lay, when Edgecumbe is the inspiring theme !
Affection for one valued, honour'd nook
Of earth, where haply first the light of day
Broke on our infant eyes, or where our cot
Uprises, render 'd precious by long years
Of residence, may throw illusive grace
Upon the hills, the vales, the woods, the streams
That sweetly circle it ; — but ilion has charms,
Enchanting mount, which not the local love
Too highly values, or the genial west
Alone enaraour'd views, — for thou art own'd
Supreme in loveliness in this our isle.
Profusely teeming with unrivalled scenes.

• Translated from the Ann. de Chim. vol. xxxvi. p. S2.

M. Berth ier's Description of' Nontronite. ^ 161

it is to this circumstance that we owe the discovery of a new
mineral, which I shall describe under the name of Nontronite.

The stratum of the manganese of Dordogne is superficial.
It consists of ferruginous clay, mixed with quartz, sand, and
a little mica. It is^evidently of the same formation as the stra-
ta of iron called alluvial, which exist in the country.

The ore of manganese is found in irregular masses more or
less considerable in the ferruginous clay ; it is a mixture of
the hydrate of the deutoxide of manganese, of the peroxide,
and of the barytic combination which prevails in the ore of
Romaneche.

Nontronite was discovered by M. Lanoue in the ore of
manganese wrought near the village of Saint Pardoux. It is
disseminated in amorphous onion-shaped masses, commonly very
small, and seldom so large as the fist. Hence round masses
are almost never pure, and divide easily into smaller masses
quite irregular, all these small masses being coated with a slight
black pellicle, which is oxide of manganese, and they are often
mixed with micaceous clay of a dirty yellow colour, so that
when we cut the mineral, and polish it, it presents the appear-
ance of a variolite. It is nevertheless easy to procure Nontro-
nite pure by a careful selection of it.

This mineral is compact, of a pale strati' colour, with a fine
canary yellow slightly greenish. It is opaque, unctuous to
the touch, and very tender. Its consistence is the same as
that of clay ; it is easily scratched with the nail ; it takes a fine
piolish and resinous lustre under the friction of softer bodies;
it is flattened, and grows lumpy under the pestle, instead of
being reduced to powder; it exhales an odour when breathed
tfpon, and does not act on the magnetic needle. When im-
mersed in water, it disengages many air-bubbles ; it becoflies
translucent at the edges with losing its form, and if at the end
of some hours it is taken oUi of the water, atrd weighed after
it is wiped, it is found to have increased onef-tenth in its
weight. When heated in a glass tube, it loses its water with
a slight heat, and takes the colour of a dirty re'd OxMe Of iron.
When calcined in a crucible, it assumes the satne aspect, and
its weight is diminished from 0.19 to 0.21. After calcination"^
it is sensibly magnetic.

152 M. Berthier'^s Description of Nontronite.

Muriatic acid attacks it very easily ; the solution does jiot
contain the smallest trace of manganese, nor protoxide of iron,
nor alkali; there were found only peroxide of iron, alumina,
and magnesia. The insoluble part is gelatinous, and is com-
posed of silex soluble in the liquid alkaries, and sometimes
mixed with a small quantity of argil, when the mineral has
not been picked with great care.

Nontronite melts readily with the third of its weight of
marble.

The analysis gives

SiHca, - 44.0 containing 22.9 oxygen.

Peroxide of ii'on, 29-0 8.9

Alumina, Z.Q 1.7

Magnesia, 2.1 0.8

Water, 18.7 1.6

Clay, - 1.2

98.6

From the quantities of oxygen in each of its elements, Non-
tronite is a bisilicate, with a base of peroxide of iron, alumina,
and magnesia, and may be represented by the formula,

and containing besides a certain proportion of water in combi-
nation ; but it is difficult to determine this proportion accu-
rately, on account of the facility with which the mineral ab-
sorbs, or loses a certain proportion of water according to the
smallest changes of temperature. We have seen indeed, that
when it is kept long immersed in this fluid, it absorbs one-
tenth of its weight of it, and contains from 28 to 30 per cent. ;
when it is left for several days in the air of a room, it con-
tains only from 21 to 22 per cent. ; and when it has been ex-
posed in a stove heated to 80° Cent., it only loses by calcina-
tion 18.7 per cent. If we admit this last quantity to be the
minimum, it will follow that the water of combination con-
tained in the Nontronite contains IJ times as much oxygen as
the three bases together.

Two cases of Insensibility of the Eye to Coloiirs, 153

A great number of minerals are known which contain among
the number of their elements a hydrosilicate of the protoxide
of iron, but none which contain a silicate of the peroxide with
water of crystallization. The Nontronite is the first mineral
of this kind. As the silicates of the peroxide of iron have ge-
nerally a high colour of either red or brown, we ought not at
first sight to conjecture the existence of it in Nontronite. The
colour of this mineral depends evidently on the presence of
water ; this colour actually disappears by calcination, and we
know salts of the peroxide, such as several sulphates, which,
when they contain water, are of a pale yellow colour, and
sometimes almost colourless.

I have said that Nontronite strongly calcined in a close ves-
sel becomes sensibly magnetic ; the silicates, however, of the
peroxide of iron do not act on the magnetic needle. This
phenomenon may be thus explained : The peroxide of ii*on is
a very weak base ; it cannot be combined with silex in the dry
way, without the intermedium of another base ; but as on the
contrary silex has a great tendency to unite itself to the pro-
toxide of iron, it happens, that when we heat to a temperature
sufficiently high this substance with peroxide of iron, a por-
tion of this peroxide abandons the oxygen, and transforms it-
self into peroxide, or at least to an oxide inferior to the real
oxide. The combination thus formed may be regarded as a
double silicate of the protoxide and the peroxide, in propor-
tions which vary according to circumstances ; but the pre-
sence of a small quantity of the protoxide is sufficient to com-
municate to a silicate the magnetic virtue, when the silica does
not exist in too great a proportion.

Art. XXV. — Account of two remarkahle Cases of Insensi-
bility in the Eye to particular Colours.

The insensibility of some eyes to particular colours is a much
more common defect than is generally believed, and it is a cu-
rious circumstance, that three of the most distinguished indi-
viduals in Great Britain, Mr Dalton, Mr Troughton, and the
late Mr Dugald Stewart, were all incapable of distinguishing
particular tints. The case of Mr ' has recently been

These were all regarded as Blues
of different shades.

154 Two cases of Insensibiliiy of the Eye

well described by a distinguished philosopher, and it is princi-
pally for the purpose of laying it before our readers that we havd
introduced the subject at present. Before doing this, however,
we shall describe the case of a young man of about twenty years
of age, the son of an eminent scientific gentleman in the vici-
nity of Edinburgh, whose peculiarities of vision were examin-
ed some years ago by Dr Brewster.

The following coloured silks he arranged into two sets of
colours, viz. blues and browns : —

Green,

Pale Blue,

Purple,

Carmine Red,

Pale Pink,

Peach Blossom,

Red Lilac Purple,

French White,

Dark Green,

Duck Green,

Vermillion Red,

Bright Tile Red,

Chestnut Brown, J

The most precise information, however, was obtained from
the following experiments : —

1. The prismatic spectrum was formed with an equilateral
prism of flint-glass, which received the light from a very nar-
row longitudinal aperture. The colours which were thus de-
veloped were four, as in Dr Wollaston''s spectrum, viz. red,
green, blue, and violet. When Mr L examined this spec-
trum, it appeared to consist only of two colours, — yellow and
bliie.

2. Wlien all the colours were absorbed by a reddish glass

excepting red and dark green, Mr L saw only one colour,

viz. yellow.

3. When the middle of the red space was absorbed, as de-
scribed in the Edinburgh Transactimis, vol. ix. p. 439, Mt

L- saw the black space with what he called the yellow on

each side of it.

The case of Mr is very nearly the same with that

now described ; but there are some peculiarities in it which
merit attention. " We have examined,"" says the distinguished

These are all regarded as Browns
of different shades.

to particular Colours, 155

philosopher who describes it, *' the eyes of an eminent optician,
whose eyes have this curious peculiarity, and have satisfied
ourselves, contrary to the received opinion,* that all the pris-
matic rays have the power of exciting and affecting him with
the sensation of hght, and producing distinct vision, so that
the defect arises from no insensibility of the retina to rays of
any particular refrangibility, nor to any colouring matter in the
humours of the eye, preventing certain rays from reaching the
retina (as has been ingeniously supposed,) but from a defect
in the sensorium, by which it is rendered incapable of appre-
ciating exactly those differences between rays in which their
colour depends. The following is the result of a series of trials
in which a succession of optical tints produced by polarized
light passing through an inclined plate of mica, was submitted
to his judgment. In each case, two uniformly coloured circu-
lar spaces, placed side by side, and having complementary tints,.
(that is, such that the sum of their hght shall be white,) were
presented, and the result of his judgment is here given in his
own words.

Colours to an ordinary eye. Colours to Mr 's eye.

Pale green, No colour.

Dirty white, Darker, but no colour.

Fine bright pink, Very pale tinge of blue.

White, Yellow. .mv^v/Oii/A

Rich grass-green. Yellow, but more coloured.

Dull greenish-blue. Blue,

Purple, rather pale. Blue*

Fine pink. Yellow, with a good deal of blue^

Fine yellow. Good yellow.

Yellowish green. Yellow with a good deal of blue.

* We were not aware that any eyes had ever been regarded as absolutely
insensible to the luminous effect of any particular rays, but only to the co-
lorific effect of these raye, though we admit that the language used in trying to
explain the peculiarity may bear this construction. When we have spoken
of an eye insensible to red light j we meant only insensible to the redness of
light.

It should be stated, however, that T. B. the subject of Mr Harvey's ob-
servations, {Edin. Trans^ vol. x. p. 253,) regarded indigo and Prussian
blue as black) and ako some greens as blacky that is, certain blue and
green rays made scarcely any impression on his retina. — Ed.

156

Two cases of Insensibility of the Eye

Colours to an ordinary eye. Colours to Mr *8 eye.

Good blue, verging to indigo, Blue.
Red, or very ruddy pink, Yellow.
Rich yellow, Fine bright yellow.

White, Very little colour.

Dark purple. Dim blue.

Dull orange red, Yellow.

White, White.

Very dark purple. Dark.

The following colours in the first column are complemen-
tary to those in the first column of the preceding table.

Colours to an ordinary eye. Colours to Mr 's eye.

Pale Pink, No colour.

The same, No colour, but darker.

Fine green, verging to

Very pale tinge of blue.

Blue.

Yellow,

Blue, with a good deal of yellow.

Good blue.

Blue, with a good deal of yellow.

bluish.
White,
Rich crimson,
Pale brick red.
Pale yellow.
Fine green.
Purple,
Fine crimson,
Yellow, varying to orange, Yellow, gay colour.
Very fine greenish-blue.

nearly white.
Full blue.
Fiery orange.
White,
White,

Dull dirty olive.
White,

Blue.

Pretty good blue.
Yellow, or blood-looking yellow.
White, with adash of yellow and blue.
White, with blue and yellow in it.
Dark.
White

Instead of presenting the colours for his judgment, he was
now desired to arrange the apparatus so as to make the strongest
possible succession of contrasts of colour in the two circles.

Colours to an ordinary eye. Colours to Mr 's eye.

Pale ruddy pink. Yellow.

Blue green, Blue.

Yellow, Yellow.

to particular Colours. 157

Colours to^an ordinary eye. Colours to Mr ~— — 's eye.

White, Blue.

Pale brick red, Yellow.

Indigo, Blue.

Yellow, Yellow.

The following colours in the first column are complementa-
ry to those in the first column of the preceding table.
Colours to an ordinary eye. Colours to Mr " 's eye.

Blue green, Blue.

Pale ruddy pink, Yellow.

Blue, Blue.

Fiery-orange, Yellow.

White, Blue.

Pale yellow, Yellow.

Indigo, Blue.

It appears by this that the eyes of the individual in question
are only capable of fully appreciating blue and yellow tints,
and that these names uniformly correspond in his nomencla-
ture to the more and less refrangible rays generally ; all which
belong to the former, indifferently, exciting a sense of " blue-
ness," and to the latter of " yellowness." Mention has been
made of individuals seeing well in other respects, but devoid
altogether of the sense of colour, distinguishing different tints
only as brighter or darker one than another ; but the case is
probably one of extremely rare occurrence."

In examining the preceding tables, we observe some results
which we think require elucidation. These are principally
such as relate to the whites, which stand thus :
Colour to an ordinary eye. Colour to Mr 's eye.

White, Yellow.

White, Very little colour.

White, White.

White, Blue.

White, White, with a dash of yellow and blue.

White, White, with blue and yellow in it.

White, White.

The examination of this table suggests some important
questions.

1. What would be the colour which results from the union

1 58 Two cases of Insensibility of the Eye to Colours.

of all the rays in the spectrum, to a person whose sensorium is
incapable of appreciating those differences between some of the
rays on which their colour depends ?

2. If the colour of all the rays thus united is white, that is,
if it makes the same impression on the defective sensorium as
a perfectly white body, how does it happen that white was seen

by Mr at one time as yellow, at another time as bhie,

and at a third time as white f

3. If the union of all the colours is not white, but is a mix-
ture of blue and yellow, the only colours which the eye of Mr

perceives, why is white seen different from a mixture

of blue and yellow ?

4. The sensorium of Mr is not only defective in the

power of discriminating colours, but it wants the power of ap-
preciating the joint influence of the colours which it does dis-
criminate, or of discovering in combination a colour which it
discriminates when seen separately. Fine crimson, for exam-
ple, is described by Mr as blue^ z&ith a good deal of

T^ellmv, which would be described by a common eye as green-
ish ; and in a rich grass green, no blue is recognized, but it
appears only yellow.

An answer may be given to some of these questions by sim-
plifying the case. If the eye was devoid altogether of the
sense of colour, the spectrum would appear light at the point
of maximum yellow, shading gradually off to both extremities,
and exactly as it would do to a sound eye if shaded off with In-
dian ink. In this case it cannot be doubted that such a spec-
trum would appear white if thrown into a circle and whirled
rapidly round.

If the eye recognized only one colour, such as yellow, the
spectrum would appear yellow in the middle, and shading off
as in the first case ; and if it were thrown into a circle and
whirled rapidly round the whole would be yellow.

If the spectrum now consists of two colours which are
alone recognized, viz. yellow and blue, we know that thieir
unionwill not he green, for the eye is insensible to this tint ; we
cannot understand how it can be white-., and therefore we con-
ceive that the retina may be affected in some points with blue
and in others with yellow, an effect which may be produced in

Remarks on Self Registering Thermometers. i 59

a sound eye by looking at a white object with a blue glass ap-
plied to one eye, and a yellow glass to the other.

The subject is obviously one attended with great difficulty,
and requires much more investigation than it has yet received.

The author of the description of Mr 's vision regards

this defect of particular eyes as presenting a formidable objec-
tion to the inference deduced from Mr Herschel and Dr
Brewster"'s experiments, relative to the overlapping of the co-
loured spaces in the spectrum. We cannot at all understand
what the objection is which is here alluded to ; nor can we con-
ceive how any inference from an obscure physiological fact
could set aside the result of a legitimate induction.

Art. XXVI,— r- Farmer Remarks on Self- Registering Ther^
mometers. Communicated by the Author.

Sir,
I SHOULD not have now thought of troubling you with any re-
marks beyond those I offered in a short notice with regard to
register thermometers in the last Number of your Journal, had
I not since accidentally met with a paper on the subject in an
old volume of the Philosophical Transactions^ to which can^
dour requires me briefly to advert.

Lord Charles Cavendish, to whom we owe some valuable
contributions to meteorology in its earliest progress, has de-
scribed, in the Traiisactions of the Royal Society of London
for J 757,* thermometers adapted for the measure of maximum
heat and cold : it would appear that Bernoulli had previously
made some instruments for the same purpose, but I am not
aware of their nature. The principle, however, which Lord
Charles Cavendish proposed, was precisely similar to the one
described by Mr King, No. xvi. p. 116, the merit of which I
was disposed to attribute to Mr Blackadder, whose account
appeared in an early number of this Journal. I feel myself
bound, therefore, in rectification of the oversight I had com-
mitted, to remark that thermometers acting by the quantity of
a column of fluid expelled from the extremity of the tube, ap-

* Page 300, or Abridgement, vol. xi. p. 138.

160 Remarks on Self-registering Thermometers.

pear to have been the first registering ones described ; since
that of Six, which acts by indices, was not described in the
Philosophical Transactions for twenty-five years afterwards, in
1782. I must first notice the construction of Lord Charles
Cavendish'^s thermometer, which had the merit of superseding
the necessity of a common attached thermometer, which is re-
quired in the construction of Mr Blackadder and Mr King.

A mercurial thermometer had the end of the tube drawn
to a capillary orifice, and was capped by a small glass recep-
tacle, exactly as represented in vol. ix. plate ii. fig. 7- and 9. of
this Journal ; above the mercury some alcohol was introdu-
ced into the tube, which of course was expelled into the glass
cistern through the capillary opening as the temperature rose,
and, as it could not draw it back when the temperature de-
clined, a space was left in the upper part of the tube, measured
by a descending scale of degrees, which gave the maximum
that had occurred since the last observation, when added to
the present temperature indicated by the height of the mercu-
ry in the tube, which never rises so high as to be expelled by
heat.

This description, it will be observed, corresponds almost
precisely with that given by Mr King, and on the defects of
which I formerly made some remarks : my objection, relative
to the uncertainty of a fall of a drop of mercury from the
orifice, I find was expressed almost verbally in the same way by
Lord C. Cavendish,* in describing another of his thermometers,
where the capillary termination could not be so conveniently
employed, and which he proposed to rectify by inserting a glass
thread into the narrowest part of the tube, an expedient more
ingenious than practicable. This was employed in the mijii-
num thermometer, where the mercury fell into a globe be-
tween the tube and the real bulb, placed at the upper bend of
a syphon-shaped thermometer ; but the construction of this

• *' If no farther contrivance was used, the mercury would fall into the
ball in large drops, which would make the instrument less accurate ; for
the thermometer's beginning to rise immediately after a drop has fallen, or
just as it is going to fall, (in which case it will return back to the tube,)
will make a difference of such part of a degree nearly as that drop an-
swers to."

Remarks on Self-registering Thermometers. 161

rather awkward contrivance I shall not now describe, as its ge-
neral principle is the same as in a thermometer which has oc-
curred to myself for exhibiting both maximum and minimum
results in the same instrument without the aid of indices,
which I believe has not before been attempted.

In Figure 5 of Plate I. the dotted portions denote alcohol,
the parallel lines mercury. The upper part of the tube, for the
measurement of the greatest heat, is exactly upon Lord C.
Cavendish's plan, and the altitude of the mercurial part of
the column A denotes the actual temperature at any moment.
The lower part of the tube is bent upwards, and passed into
a cylindrical bulb B, close to one side of it, as shown in the
figure. It likewise terminates in a capillary orifice, and, as
by the contraction of the alcohol which fills the almost entire
bulb, the mercury is withdrawn from the tube and falls to the
bottom, the measure of minimum temperature in any period
will correspond to the existing temperature, (marked as before
by the height of the mercury A,) rninus the degrees of the.
tube next the bulb, which contains alcohol, measured by a
small scale of their own.

The adjustment of the instrument for a new observation is
necessarily somewhat complex. It must first be reversed, and
the bulb heated with the hand till the column of alcohol joins
the quantity which has been expelled into the upper cistern ;
retaining the same position, the bulb must be cooled with
ether or some evaporating fluid till the alcohol has retired
from the lower extremity of the tube ; when, from th^
position, the mercury will obviously join with the portion
which before lay in the bottom of the bulb ; and by again
heating it with the hand till it has nearly regained the temi
perature of the air, which was known at first by an observa-
tion of the summit of the mercury, all the uncertainty will be
done away as to when the instrument has regained its proper
temperature, which in my former paper I noticed as an error
of this principle. By a httle practice, too, the degree of heat
given artificially will be so nearly proportioned to the atmo-
spheric temperature, that little time will be required to wait in
making the adjustment. With regard to the necessity of ether,
it is to be observed, that it does little more than counterba-

VOL. X. NO. I. JAN. 1829. L

162 Remarks on Self -registering Thermometers.

lance the use of a magnet to adjust Six's indices, which often
requires to be a powerful one, and to meteorologists who ob-
serve a dew-point hygrometer it will be no inconvenience
whatever. The method proposed by Lord C. Cavendish to
adjust his minimum thermometer appears to be precluded in
practice, where the tubes are of moderate bore, as it sup-
poses the free passage of the mercury in drops through the
alcohol in the tube. Perhaps in executing the thermometer
I have now proposed, it might be advisable to have a detach-
ed thermometer for the positive temperatures at the moment
of observation, and this would preclude the necessity of hav-
ing any fluid but mercury in the upper portion of the instru-
ment. The less contact we have between the alcohol and mer-
cury, I am inclined to think, the instrument would be more
perfect, since the successive passage of two such fluids through
the same tube must render it liable to be soiled. Indices,
however, at least when they are furnished with springs and
moved with the magnet, are, I think, the most detrimental to
the perfection and general adoption of the register thermo-
meters. Not merely are they troublesome to adjust, and liable
to go out of order, but their formation is always imperfect :
for it is difficult to extirpate the air from the interior ; and the
bulbs and tubes must be so large for the admission of the in-
dices as to destroy all confidence in their sensibility. The
principal advantage I therefore hold out, in the adoption of
thermometers similar in construction to the one I have here
described is, that they may be made to any degree of delica-
cy ; and the finest capillary tubes with small bulbs are in fact
more suited to the principles of the instrument, than the larg-
est and widest, which can be said of no other species of self-
registering thermometers. I need only mention how unfit
either Six's or Rutherford's thermometer, as made by the best
makers, are for nice experiments. The former has two contacts
of alcohol and mercury, as in my thermometer, and two in-
dices besides. For ascertaining maximum and minimum tem-
peratures for a short period of time, and with any delicacy,
such as in sending instruments, by means of small balloons,
to the higher regions of the atmosphere, all the ordinary ones
«ire quite unsuited ; and it is not till register thermometers

Dr Brewster's account of ttvo remarkable Rainbows. 1 63

are considerably improved and simplified, and much more ge-
nerally adopted, that we can look for very extended deduc-
tions of value in this branch of meteorological science. I am.
Sir, your most obedient servant, A

Art. XXVII. — Account of two remarkable Rainbows, one of
which enclosed the Phenomenon of converging' Solar Beams.
By David Brewster, LL. D., F. R. S. Lond. and, Edin.

On the 5th July 1828, there was seen here the most brilliant
rainbow that I had ever an opportunity of witnessing. Both
the outer and the inner bow were perfectly complete, and
equally luminous in all their parts ; and they continued in this
condition for a very considerable time. I was thus enabled to
verify, in every part of the two bows, the fact which I pub-
lished more than fifteen years ago, of the polarization of the co-
loured light, in planes passing through the centre of the bow,
or, what is the same thing, in the planes of reflection, within
the drops of rain. Similar portions of the inner and the outer
bow were thus seen to disappear simultaneously, when seen
through a plate of tourmaline.

The pecuHarity in this rainbow, which has induced me to
describe it at present, has I believe never before been noticed.
On the outside of the outer or secondary bow, there was seen
distinctly a red arch, and beyond it a very faint green one,
constituting a supernumerary rainbow, analogous to those which
sometimes accompany the inner bow. It will be interesting
to ascertain, if Dr Young's ingenious theory of the common
supernumerary bow will apply to the present one.

On the afternoon of Thursday, the 2d of October, a rain-
bow appeared in the north-east, with considerable brilliancy,
and was accompanied with the rare phenomenon of the converg-
ing of the solar beams, described in this Journal, No. iii. p.
136. As the point to which the solar beams converged below
the horizon was exactly opposite to the sun, and, therefore,
necessarily coincident with the centre of the rainbow, the two
phenomena, when thus accidentally combined, had a very re-
markable appearance.

164 Analysis of Scientijlc Books and Memoirs.

Art. XXVIIL— analysis OF SCIENTIFIC BOOKS AND ME-
MOIRS.

Elements of Natural History, adapted to ike present state oftlie Science,
containing the generic Characters of nearly the whole Animal Kingdom,
and descriptions of the principal Species. By John Stark, F. R. S. E.
Member of the Wernerian Natural History Society of Edinburgh, &c.
2 vols. 8vo. Edinburgh, 1828. Pp. 1044. With Plates.

We know of no work connected with the subject likely to be more use-
ful than the present. Natural History, like the other physical sciences, has
within the last twenty years made such progress, and the discovery of new
and the investigation of known objects, has occupied such a large share of the
attention of the continental writers, that the preceding works on Natural
Science give but a faint notion of the numbers, structure, and connection
of living beings. In France, particularly, expeditions have been fitted out
by government for the purpose of investigating the natural productions of
distant countries, and the philosophers at home, among whom are the
highest names in science, have been no less industrious in availing them-
selves of all the lights which minute observation and careful dissection af-
ford for tracing the structure and functions of living beings. This infor-
mation, scattered through an immense number of volumes, many of them
by no means of easy access, and in foreign or dead languages, presented
powerful obstacles to the general acquisition of knowledge on this impor-
tant branch of physical science. In the English language, except Dr Tur-
ton's translation of Gmelin's edition of the Systema Natures of Linnaeus,
and the Elements of A'aiural History, by the late Mr Charles Stewart, also
a translation from Linnaeus, there existed no general work calculated to
excite or gratify a taste for natural history by an explanation of its princi-
ples, or an enumeration of the genera and species. The General Zoology
of Dr Shaw, in fourteen volumes 8vo, was left imperfect by the death of
the author; but, independent of other objections, the expence of a work of
such extent, illustrated with figures of the animals, must have confined its
circulation within narrow limits. In the French language Cuvier's Regne
Animal is a masterly outline, but totally useless to the student as far as
regards generic characters and the enumeration of species. An English
translation of this work by Mr Griffiths, with figures and descriptions of
new animals, is now in progress. Dumeril's Elements is confined to an ex-
position of general principles ; and the German manual of Blumenbach,
translated some years ago into English, is merely a short sketch on the Lin-
naean principle for the use of his pupils. In short, a work was wanted, in
which, besides general considerations on the form, structure, and arrangement
of natural bodies, and other elementary information, the generic characters
of the whole should be given, as well as descriptions of the principal species.
This we understand from his prefatory notice was the intention of Mr Stark
in the present work ; and, so far as we have had leisure to examine, it seems
well calculated to serve all the purposes of the student or traveller, by en-

Starh^s Elements of Natural History. 16*5

abling them to identify and class the greater number of species they are
likely to meet with.

This work, from the multifarious nature of its contents, is scarcely sus-
ceptible of analysis ; as it is itself a scientific analysis of all the late disco-
veries and improvements in Natural History. Combining with the gene-
ral views of Cuvier the investigations of other writers on the different de-
partments of Nature, we are presented, under the modest title of Elements,
with a connected view of the Animal Kingdom, characters of nearly the
whole genera, and the greater portion of the ascertained species. With-
out entering into details upon the minutiae of generic and specific distinc-
tions, we shall give a short analytical view of the principal classes.

Natural History, Mr Stark remarks, in its most extensive sense, includes
the whole material world. k\\ that is on the earth or around it — the atmo-
sphere— the heavenly bodies — land and water — is the province of the natu-
ralist. The attributes of animated beings, — the constituent principles of
unorganized bodies and their afllnities, — the " stars in their courses,"-—
and even man himself, whose power and intelligence raises him so far
above the level of the beings around him, and connects him with the Supreme
Intelligence, is in his mortal part subjected to the same general laws which
regulate the other parts of the organized creation, and his history, animal
and intellectual, forms part of the great science of nature. " A field so exten-
sive, compared with the limited powers of the human faculties, is too vast
for the subject of individual research ; and in detail, its objects are so nu-
merous, that to possess a knowledge of even a small portion of these, has
been considered a competent task for a life spent in investigation."

In this view all the sciences have their origin in the study of nature ;
but to facilitate the acquisition of knowledge, it has become matter of ne-
cessity to subdivide and arrange the objects of the material world into por-
tions suitable to the human pov/ers. Hence has originated the division of
Physical Science into Natural Philosophy, — Chemistry, — and Natural His-
tory, properly so called fnihe last being limited to the consideration of the
Animal, Vegetable, and Mineral Kingdoms, as they have not unappropri-
ately been termed. " To examine and arrange these in connection with
the laws by which they are governed ; to investigate their structure, their
history, and their uses, is the province of the naturalist." Natural History
is besides distinguished from the other itvvo great divisions of physical
science, in that, while the several branches of Natural Philosophy rest
chiefly on calculation, and Chemistry on experiment, its basis rests princi-
pally upon observation.

The term Nature^ Mr S. remarks, bears various significations. It is
sometimes used to signify the properties which a being derives from ori-
ginal conformation in opposition to those which it has acquired from art ;
sometimes to express the whole objects which compose the universe ; at
other times the laws which regulate this universe ; and these laws being,
in point of fact, the will of that beneficent and omnipotent Being who
formed all this " gay creation," the word Nature is frequently employed
by a figure of speech to designate its Great Author.

The first great division of natural objects is into organic and inorganic

166 Analysis of Scientific Books and Memoirs.

hoilies ; the first including Animals and Plants — the second Minerals.
These are further arranged inta tliree principal divisions, appropriately
enough called Kingdoms. Animals have been defined, as organized bodies
possessing life, sensation, and voluntary motion : — Vegetables organized
bodies endowed with a vital principle, but destitute of sensation and the
power of locomotion : — and Minerals as unorganized bodies destitute of
life, and of course of sensation. Animal life is distinguished from vege-
table life by many considerations, of which we only mention two — Life in-
the first is active — in the second passive. The nourishment of plants is deri-
ved through the medium of their roots ; that of animals through a central
organ of digestion destined to receive the food. All living bodies, how-
ever, possess some characters in common, as absorption, assimilation, de-
velopement, and reproduction : all have a limited and determinate term
of life according to the species ; and while nature as a whole exhibits the
picture of perennial youth and interminable existence, each individual
leaves the scene to make room for others at an allotted term.

After detailing the forms and structure of these three great divisions of
natural bo^lies in a general introduction, Mr S., under the head " Animal
Kingdom," gives, as the basis of the arrangement which he has followed,
an outline of the method proposed by Cuvier, founded upon the compa-
rative organization of the animal races. Animals are thus divided into
1. Those possessed of a skull and vertebral column, in which the nervous
matter is inclosed, or Vertebrata ; and 2. Those destitute of a vertebral
column and internal bony skeleton, or Invertebrata. These last are
divided into 1. Molluscous Animals, including those in which the muscles
are simply attached to the skin, and which are either without other cover-
ing, or have the soft body protected by a shell. 2. Articulated Animals,
in which the covering of the body is divided by transverse folds into rings
or segments, to the interior of which the muscles are attached : and 3.
Radiated Animals, or those in which the organs of movement and sensa-
tion have a circular or radiated form round a common centre. This divi-
sion includes the Polypi or Zoophytes.

The first class of Vertebrated animals is the Mammalia. To this class
is prefixed an introduction, giving a short history of the principal writers
on this branch of natural history, — a description of the general forms and
structure of the animals of the class, — the methods which have been propos-
ed for classifying them by various authors, — and their uses in the economy
of nature. Tiiis is followed by the detailed characters of the orders, fami-
lies, genera, and species. The Mammalia are arranged by Cuvier into
eight orders — by Mr Stark into ten — Cuvier having placed the Cheiroptera
and Marsupialia as two families of his order Carnassiers. These orders
are, 1. Bimana ; 2. Quadrumana ; 3. Cheiroptera ; 4. Feras ; 6. Marsu-
pialia ; 6. Glires ; 7. Edentata ; 8. Pachydermata ; 9. Ruminantia
10. Cetaceii. At the head of the class stands man, the isolated species of
the order Bimana, so different even in physical conformation from all the
other tribes of animals. " Man stands alone in the order and genus to
which naturalists have referred his species. Distinguished by reason and
the power of speech, this wonderfully constructed being seems the bond

Stark's Elements of Natural Hhtorij. 167

of connection between the material and immaterial worlds. While the
inferior animals enjoy unalloyed the blessings of life and present enjoy-
ment, man combines the past, the present, and the future, in his calcula-
tions of happiness ; and while some parts of his organization connect him
with the creatures around him, and sober his rule over beings with animal
feelings of pleasure and pain as acute as his own, his intellectual powers
trace the Divinity in all the parts of creation, and connect him with the
Great Author of his Being." — " The physical structure of man also widely
separates him from the other portions of the mammiferous class. But
these variations in form and proportion are neither so prominent nor so
totally different in character from the other animal structures, as to account
for the superiority which he enjoys. Destined to be nourished on sub-
stances used in common by other animals, the mechanism of his frame
must so far correspond with theirs, as to be able to convert these substances
to the fluids which support his animal life ; and his organs of sensation
must necessarily be analogous in some degree to those of beings on whom
the material world is destined to make similar impressions. But no mate-
rial organs which Man possesses, abstracted from the raind of which they
are but the instruments, can account for his intellectual supremacy ; and
all those hypotheses which would trace Man's intellectual and moral powers
from the absolute or relative size of the brain or other material organs, have
miserably failed in connecting mind with matter, or thought with organic
structure." — " In other respects Man appears to possess nothing resemb-
ling the instinct of animals. He is not stimulated to any regular or con-
tinuous exertion of industry by an uncontrollable impulse. His knowledge
is the consequence of his own sensation and reflection, or of those of his
predecessors ; and from these results, transmitted by language or example,
and applied to his various wants and enjoyments, have originated all the
arts. Language and letters, by affording the means of preserving and com-
municating acquired knowledge, hold out to the huma« race indefinite
sources of improvement." After some remarks on the varieties of the hu-
man species, Mr S. adds, " Some French naturalists have endeavoured to
raise the varieties now observable among the human race into different
species ; but, as Cuvier justly remarks, 'the indiscriminate sexual inter-
course and consequent production of an offspring capable of propagation
prove mankind to be but a single species. And it is remarked by Blumen-
bach, that all national differences in the form and colour of the human
body are not more remarkable, nor more inconceivable, than those by which
varieties of so many other organized bodies,, and particularly of domestic
animals, arise as it were under our eyes."

The second order of Mammalia is the Quadrumanous Animals. These
approach nearest in bodily structure to man. Of the first family it is re-
marked, that, " if the conformation of the body always implied corre-
sponding intellectual attributes, the Simioe or apes should approach the
nearest to man. But this is not found to be the case; and though the fa-
mily of apes have, like man, their anterior hands free, and opposable thumbs,
though in a less degree, yet it is not found that their sagacity is superior
or equal to some other tribes of mammiferous animals. The structure of
their body, indeed, enables them to perform many movements similar to

163 Analysis of Scientific Books and Memoirs.

man, but this, when it approaches the usages of the human race, is iu ge-
neral the mere effect of imitation or education in individuals withdrawn
from their kind. Possessed of hands at both extremities, capable, were
they directed by intelligence, of turning the soil or tlie inhabitants of the
forest to their use, they are inferior in sagacity to the beaver and many
other animals which live in society. The social instinct of the apes indeed
seems limited to the tendency which frugiverous animals have in general
to live in wandering troops, for the purposes of mutual protection." In
this division an interesting account is given of the great ourang-outang, the
Sitnia Satyrus of Linnaeus or the Pongo of Wurmb, a gigantic animal,
whose height, when full grown, exceeds seven feet and a half.

The third order. Cheiroptera, including the Galeopitheci and Bats, to the
singular membrane extended between their fore-feet and fingers in the form
of wings, which enables them to fly like birds, adds two pectoral mammae, and
have the male organ of generation similar to the preceding order. Next
comes the order Ferce, part of the Carnassiers of Cuvier, divided into three
families, Inseciivora, Carnivora, and Amphibia. We would willingly here
copy some of the notes in whfch the history and habits of the most in-
teresting species are detailed did our limits permit. Regarding that very
useful and widely distributed animal, the Dog, it is stated, that ** the
domestication of this animal is, in Cuvier's opinion, the most complete,
the most singular, and the most useful conquest man has ever made. All
the species have become his peculiar property ; and each individual, de-
voted to his master alone, accommodates itself to his manners, protects his
goods, and remains attached to him till death. This connection arises not
from constraint, nor from the want of man's protection ; for the dog has
naturally powers of defence and attack superior to most of the quadrupeds,
but from a species of confidence approaching to friendship. Its strength,
its speed, and its smell, have made it a powerful ally in the subjugation of
the other animals; and itis the only animal which has followed man through
every quarter of the globe, and the only one whose existence and propaga-
tion does not seem to be determined by certain limitations of latitude."

" The bodily strength of the lion, his carnivorous regimen, and preda-
ceous habits, place him at the head of the beasts of prey. Less savage than
the tiger and other carnivorous animals, the lion seems to derive no grati-
fication from the destruction of animal life beyond the immediate cravings
of appetite ; and hence, compared with the cruel dispositions of many of
the minor inhabitants of the forest, he has acquired a character of genero-
sity superadded to his courage, which has long made him be regarded as
the noblest of the feline race. Unlike the tiger, whose social attachment,
lasts only during the period of reproduction, and whose thirst for blood
■ often leads him to destroy his own issue, the lion is permanently attached
to his mate ; while the maternal feeling of the lioness is strikingly display-
ed in the subsequent fury of this noble animal when by any accident she
is * bereaved of her whelps.' "

The fifth order, Marsupialia, are those singularly constructed animals
in which the young are for some time protected in an abdominal pouch,
in which also the mamma; are placed. The Glires or gnawers form th«
sixth order. To this division belong the beaver, distinguished for its in

StarJc's Elements of Natural History. 169

telligence and social instinct — the Lemming, well known for its migratory
habits — the rat, the mouse, the hamster, the marmot, as well as the squir-
rel, the porcupine, and the hare. The peculiarities of these animals are
described in notes at considerable length.

Order seventh, Edentata^ includes the Bradypus or sloth, the ArmadillOj
the Echidna, and the Ornithorynchusy the singular anatomy of the two last of
which has been so ably illustrated by the dissections of Sir Everard Home
and Dr Knox. Order eighth, Fachyderma, divided into three families, viz.
Proboscidea, Pachyderma, and Solidangula, includes the largest of quadru-
peds, the elephant, the mammoth, and the hippopotamus. We copy the note
regarding the first of these : — " The Elephant is the largest of existing quad-
rupeds, and has been known from the earliest ages. The Asiatic species is
found throughout the whole of Southern India and the neighbouring islands;
but though extensively employed it can scarcely be considered as a domestic
animal, as it does not breed in captivity. The supply is therefore kept up by
the capture of wild ones; and elephant-hunting forms a princely sport among
the inhabitants of Asia. The elephant inhabits forests in the neighbour-
hood of rivers, and swims with great ease. It is a gregarious animal, and
is generally found in herds, sometimes to the amount of hundreds together.
Its extreme docility renders it easy to be tamed ; and numerous facts have
been related of its sagacity in a state of domestication. The specimen long
in Mr Cross's collection at Exeter Change, and which he was forced to kill
to preserve the building, was between 10 and 11 feet in height, and weigh-
ed by computation between four and five tons. Its daily allowance of food
was three trusses of hay, about 200 lbs. of carrots and other fresh vegeta-
bles, and from 60 to 80 gallons of water. A strong elephant can carry
2000 pounds weight and travel 60 miles a-day ; though in long marches its
feet are apt to become tender. The period of gestation is twenty months.
At birth the young elephant is about three feet long, and it sucks with its
mouth, putting back the proboscis when doing so. It arrives at full growth
in about twenty years ; and lives, according to the opinion entertained in
India, for three centuries, witnessing the successive rise and decay of the
ephemeral generations of men. The tusks, an object of commerce, are
changed but once during the life of the animal, but the molar teeth are
renewed as often as detrition renders it necessary. These teeth, however,
are not renewed in the usual manner, by the new teeth pushing out the
old ones, but by a lateral succession from back to front. The most won-
derful part of the structure of the elephant is its proboscis, which to it
serves all the purposes of a hand ; and while it is able with this powerful
instrument to lift the greatest weights, its lip possesses all the delicacy of
a finger, and is capable of seizing the smallest substances. — The white
variety is rare, and is held in much esteem by the eastern sovereigns.
Horace alludes to its exhibition in ancient Rome, Epist. i. B. ii."

To this division also belongs that very useful animal, the Hog. '^ The
fecundity of the hog is very great. A hog belonging to Mr Thomus Rich-
dale, Leicestershire, had produced, in the year 1797, three hundred and
fifty young ones in twenty litters ; four years before it brought forth two
hundred and five in twelve litters ; and in Vauban's opinion in twelve ge-
nerations the produce of a single pair would produce as many as Europe

170 Ayialijsis of Scientific Books and Memoirs.

cbuld support. Among the ancients the hog was in much esteem ; it was
the peculiar sacrifice to Ceres ; and in the island of Crete it was regarded
as sacred. In ancient Rome the art of rearing and fattening them was
much studietl, and a dressed hog was among the most expensive of the
imperial dishes."

The third family of this order includes the horse. " The different races
of the horse are numerous, most of the principal countries in the world
possessing breeds peculiar to themselves. But the Arabian race has long
been consideretl as the noblest of the species, and as combining the quali-
ties of endurance, vigour, and temper, in a higher degree than any of the
other varieties. As breeders of horses have ascertained that the qualities of
the Arabian horse may be perpetuated in his descendants, in the countries
of Europe where attention is paid to the raising of this valuable animal
for various purposes, the deterioration which a northern climate induces
in a native of warmer latitudes is counteracted by crossing with the origi-
nal breed. From the importation of the pure breed of Arabia into Europe,
and the different crossings of these and their descendants with the native
breeds, has arisen all that variety in appearance and qualities of the horse,
which fits them for heavy draughts, the plough, or the saddle."

The ninth order of Mammalia is the Ruminantia or Ruminating ani-
mals, including that large group of quadrupeds which possess the singular fa-
culty of masticating their food twice, and among these the goat, the ox, and
the sheep. At the head of this order stands the Arabian Camel, which has
from ages been the medium of commercial communication between the
countries on either side of the great deserts of Arabia, and has been emphati-
cally termed the ship of the desert. We notice here also the Reindeer, the
only one of the genus Cervus which has been domesticated ; and the Gi-
raffe, known to the Greeks and Romans, and which has after along interval
been again brought alive to Europe. The last order of mammiferous ani-
mals is the Cetacea, which, to the form and habits of fishes, join some of
the essential characteristics of quadrupeds. This order includes the Dol-
phin, the Porpoise, and the Whale, the largest of animals, the mass of the
body of a full grown specimen being nearly equal to that of a hundred ele-
phants.

" The total number of mammiferous animals described by Desmarest
(and Mr S. has inserted the whole ascertained species) is about 850, includ-
ing, however, many species imperfectly ascertained and the fossil Mammalia;
of which belonging to the order Quadrumana are 141, — Cheiroptera 97, —
Ferae 176,-— Marsupialia 47,— Rodentia 149, — Edentata 24,— Pachyder-
mata 35,— Ruminantia 97,- Cetacea 62. Of these about 330 are frugi-
vorous or herbivorous, 80 omnivorous, 150 insectivorous, and 240 carnivo-
rous, in a greater or lesser degree. The number of terrestrial species do-
mesticated by man (but perhaps including all that are really useful)
amount only to thirteen.

We have thus shortly enumerated the principal divisions adopted by Mr
S. in the class Mammalia, without attempting to give any of the scientific,
generic, and specific descriptions ; and omitting entirely the general con-
siderations on the anatomical structure, food, and habits of the different
groups. For these we refer to the book itself. We only remark, that Mr S.
has very properly followed Cuvier and Desmarest in the distinctions of ge-

Stark^s Elements of Natural History. 171

iiera and species ; and that in the popular details much of the wonderful
related by travellers is softened down to the capability of sober belief, with-
out lessening the interest excited by the real wonders in the structure
and instincts of living beings.

The second class of Vertebrated Animals, Birds, next follows ; and here
the scientific details are also preceded by an introduction explaining the ana-
tomical peculiarities of structure, the general forms and habits of this group
of animals, with explanations of the terras used in description, and a his-
torical summary of the chief methods of arrangement. " The arrangement
of Birds into orders (says Mr S.) has for its basis the conformation of
the bill and feet, which are adopted to their different modes of living and
food. Birds of Prey are characterized by a hooked bill, and feet armed with
strong and crooked nails ; Climbers are those, the structure of whose feet
is calculated for motion on an inclined or vertical surface ; and web-footed
birds are evidently adapted for swimming. Others again have the legs
very long and naked for wading ; and a large number, with the claws short
and feeble, live chiefly on insects. But though it be thus easy to separate
the more strongly marked groups into extended families, yet it has been
found extremely difficult to distribute them in subordinate groups, so as
to facilitate the knowledge of species in a class so widely extended. In
adopting the arrangement of Temminck, therefore, though his Orders are
more numerous than those proposed by Cuvier and Vieillot, yet the fa-
milies of the latter are in much greater number ; and in an elementary
work it has been judged proper to follow that system which involves the
least change of the established nomenclature as likely to be most generally
useful." The number of orders in this class, which it is not necessary to
enumerate here, is sixteen, and Mr Stark gives, besides the generic charac-
ters of the whole class, descriptions of all the European species, and the prin-
cipal foreign species. The notes on this portion are extremely interesting, and
convey much information not generally known- We copy one or two of
the general remarks. " The Class of Birds, though not so apparently use-
ful to man as the Mammalia, serve important purposes in the general eco-
- nomy of nature. Those whose food is chiefly insectivorous check the ex-
cessive reproduction of the insect races, and for this purpose migrate at cer-
tain seasons to places where their food abounds. The indiscriminate de-
struction of crows and sparrows in some districts has accordingly been found
to give rise to an infinitely more prejudicial multiplication of creatures still
more destructive. Some families of birds destroy field-mice, snakes, frogs,
and lizards; and others again are led by choice to feed on carrion, or dead
animal matter. Birds are, besides, extensive agents in the spread of vege-
tables and even animals. It is well ascertained that wild ducks in their
emigrations carry impregnated spawn into remote ponds, and thus stock
them with fish ; and many, by swallowing seeds .whole, and subsequently
expelling them, are tlie means of spreading vegetation over an extent of
surface which scarcely any other means could accomplish. A great por-
tion of the class and their eggs may be used as food, and the feathers of
many form an object of commerce." — " The flights of migratory birds
have been noticed from the earliest periods. — * The stork in the Heaven
knoweth her appointed times, and the turtle and the crane and the swal-

172 Analysis of Scientific Books and Memoirs.

low observe the time of their coming ;' and, as if their passage through the
air or the structure of their bodies made them sooner perceive the incipi*
ent changes of weather, the appearance and cries of birds have long been
considered to afford presages of the coming storm or the cessation of tlie
tempest. The institution of a College of Augurs at Rome may therefore
be conceived to have reference to something better than mere superstition;
and though the flight of particular species might, in the hands of interest-
ed individuals, be made to presage the wished-for result of a battle, or di-
rect a march already determined on, yet in the absence of the barometer
and thermometer the appearance or disappearance and cries of birds was the
signal to the husbandmen to sow his fields or to secure his crop.

Jam veris praenuncia venit hirnndo.--~Ovid.

Turn cornix plena pluvivvm vocat improba voce.— Firg.

*' In this country the great migrations of birds take place in spring and au-
tumn. Those which arrive in spring come from warmer climates, and af-
ter incubation leave us in autumn ; and another host, chiefly Palmipedes,
from the arctic regions, arrive in autumn, and pass the winter on our lakes
and shores, departing again in the spring. Each species has a particular
mode of flight in these annual journeys, and a certain period of arrival and
departure. Assembled in large flocks the cranes cleave the air in the form
of a long triangle ; wild-geese fly in angular lines ; and the smaller birds
associate in less numerous families, and reach their destination by less con-
tinued flights.'*

The third class of Vertebrated Animals or Reptiles is treated as the pre-
ceding classes. The orders are four, viz. Chelonian Reptiles or Tortoises ;
Saurian Reptiles or Lizards ; Ophidian Reptiles or Serpents ; and Batra-
chian Reptiles or Frogs. To this class belong the crocodile of the Nile,
known from the earliest times, and apparently much more common former-
ly than at present, as Scaurus during his sedileship displayed no fewer than
five of these animals in an artificial lake for the gratification of the Roman
populace ; the celebrated Chamaekon ; and the most dangerous serpents.
Fishes form the fourth class of Vertebrated Animals. These are divid-
ed into two sub-classes — distinguished as Cartilaginous or Osseous, and
into nine orders, according to the form and position of their branchia; or
gills, and fins. On this important class of animals the general details are
full, and the hst of species numerous. We quote only one passage. " The
amazing reproductive powers of fishes are well known. In the ovary of
the Cod in December were found 3,686,760 ova ; in the Flounder in March,
1,357,400 ; in the Herring in October, 36,960 ; and in the Tench 383,252.
And Bloch relates, as the result of an experiment regarding the reproduc-
tive power of the Carp, that, in a pond of seven acres, in which were plac-
ed four males and three females, the increase was 110,000 young carp,~a
number far too great for the size of the pond, and the necessary supply of
food. But this astonishing capability of increase is modified by a thousand
circumstances which regulate the number produced to the supply of their
food. Myriads of these ova form the food of different species ; and myriads
more of the young may be supposed to be destroyed in an element where
almost all are destined to become the prey of one another. But not with-

StarJc's Klement.s of Natural History, 1 73

standing these deductions, the importance of this class as an object of com-
merce, and as a supply of food, hold out an inexhaustible field for the en-
terprise of nations whose territories approach the sea.

" Of the migrations of fishes, and the causes which prompt these annual
influxes of certain fishes on certain coasts, little is with certainty known.
Probably they are regulated by the same causes which influence the migra-
tions of birds, — to find food and proper places for reproduction ; and the
same instinctive impulse which induces the salmon at certain seasons to as-
cend rivers, may bring myriads of fishes to the shores for the same purpose.

'' Little is known with regard to the comparative age of fishes. The
carp has been known to reach 200 years, and the pike to 260 ; and if the
whale be found of less size now than in former ages, when their fishery
was but little attended to, it may be conjectured, that their age is still
more considerable."

In these four classes, which compose the first volume of the work, besides
the recent genera of animals, Mr S. has also given in their place the cha-
racters of the fossil genera, and has thus, by placing the former with the
present races of animals, connected Natural History with Geology. The
volume is concludc^l with a chapter on the Preparation and Preservation of
Objects in Natural History ; a List of the principal Writers on the different
classes ; and characteristic Engravings, exhibiting the various forms and
structure of the animals, upon which the leading characters of their dis-
tribution is founded.

The Second Volume contains the Invertebral animals, under the heads of
MoLLuscA, Articulata, and Rabiata. The first division contains four
classes, viz. Mollusca proper, Conchifera, Tunicata, and Cirripeda. The
second the Annelides, Crustacea, Arachnides, Myriapoda, and Insecta.
And the third division includes the Echinodermata, Entozoa, Acalepha,
Polypi, and Infusoria. This Volume is concluded by a short sketch of
the Vegetable Kingdom, exhibiting the arrangement of Linnaeus, and the
Natural orders of Jussieu ; and an Introduction to Mineralogy and Geology.

After the analysis which we have given of the first volume of this im-
portant and valuable work, it is almost superfluous to add any farther re-
commendation of it. There is indeed no English work that comes in
competition with it, and therefore it must be regarded as supplying an im-
portant desideratum in the literature of Natural History. To the Student
of Nature, and particularly to the Traveller, we would recommend it as
invaluable. Even the learned naturalist, who may possess many of the
best materials to which Mr Stark has had access, will find it a most useful
manual ; while the general reader will obtain much amusing and in-
structive information, in the account which Mr Stark has given of the
structure, functions, manners, and habits of many of the species.

The technical arrangement of the materials is judicious, the style is
simple and perspicuous, and a right tone of feeling pervades the whole
work.

The volumes are terminated with copious Indexes, with Descriptions of
the Plates, and a List of Works on Natural History.

174 Proceedings of Societies.

Art. XXIX.—PROCEEDINGS OF SOCIETIES.

1. Proceedings of the Royal Society of Edinburgh.

November 24/A, 1828. — At a general meeting of the Society held this day,
the following were elected Office-bearers and Counsellors.
Pkesident— Sir Walter Scott, Baronet.
Vice-Peesidents. — Right Hon. Lord Chief-Baron, Professor Russel,

The Hon. Lord Glenlee, Hon. Lord Newton,

Dr T. C. Hope, H. Mackenzie, Esq.

General Secretary. — John Robison, Esq.
Secretaries to the Ordinary Meetings. — P. F. Tytler, Esq.

Rev. E. B. Ramsay, A. B.
Treasuser.— Thomas Allan, Esq.
Curator of the Museum and Library. — James Skene, Esq.
Counsellors. — Sir T. M. Brisbane, Bart, Dr Alison,
Hon. Lord Meadowbank, Dr Brunton,
Dr Graham, Dr Brewster,

Thomas Kinnear, Esq., Captain Basil Hall, R. N.,

James Hunter, Esq., Sir Henry Jardine,

Sir William Hamilton, Bart., Professor Jameson.

Dec. 1. — A paper was read, entitled " Observations on Topographical
Modelling and Delineation." By William Bald, Esq. M. R. I. A. and F.
G.S.

2. Proceedings of the Cambridge Philosophical Society.

November 10, 1828. — The Reverend Professor Gumming, Vice-Presir
dent, in the chair.

A paper by J. Challis, Esq. Fellow of the Trinity College, was read. On
the law of the planetartj distances as applied to the Satellites. In the case of
the planets, it is w^ll known that if we take the excesses of their distances
above the distance of Mercury, these excesses form a geometrical series, of
which the common ratio is 2. Mr Challis has examined the distances of
the satellites from their centre, with a view to ascertain whether a similar,
law prevails with regard to them ; and from the results of his calcAlationsj
it appears incontesiible that this curious analogy, hitherto entirely unex-j
plained, obtains in the secondary as well as in the primary systems. The]
common ratio in the case of Jupiter is 2^ nearly. In the case of Saturn it]
appears to be 2 for the first five, and 3 for the last three. In the case
Uranus the ratio is \\ nearly. Mr Challis suggests that the apparent irre
gularity in the case of Saturn may be connected with the disturbing influ-?
ence of his ring. In the system of Uranus it is necessary to suppose 9]
satellites ; and thus, in the same manner in which the law applied to th<
planets led astronomers to conjecture the existence of a planet betweei
Alars and Jupiter, it leads us to suppose, when we apply it to the satellit
of Uranus, that there exist, as yet undiscovered, two satellites between the
fourth and fifth, and one between the fifth and sixth of those at preseni
known.

Scientific Intelligence — Astronomy. 1 75

Mr Whewell gave an account, illustrated by drawings, of the Phenomena
of granite veins in Cornwall, especially at Trewavas Head, Polmear Forth,
and Wicka Pool.

November 24, 1828. — The Bishop of Lincoln, the President, in the
chair.

A memoir was read by Professor Airy On the Longitude of the Cambridge
Observatory. He observed that differences of longitude, as determined by
geodeiical operations, and by differences of sidereal time, do not necessarily
coincide. They depend upon different definitions and are useful for dif-
ferent purposes. The geodetical longitude of Cambridge Observatory from
Greenwich, as proved by the trigonometrical survey, is 24" 6. of time east.
But on the 21st, 22d, and 23d of October last, a comparison of the transit
clocks at the two places was made by means of six pocket chronometers,
carried four times from one place to the other ; and this gave the astrono-
mical difference of longitude 23" 54. which Professor Airy considers as the
quantity to be used in future.

A paper was also read by Mr Willis of Caius College, On the Vowel
Sounds ; and after the meeting experiments were exhibited illustrative of
the doctrines asserted. It appears that the vowel sounds may be produced
by means of a loose reed in the order /, e, a, a, o, o, u, by successively con-
tracting the aperture of the cavity in front of the reed. It appears also,
that by fitting on a tube of gradually increasing length, the sounds pro-
duced are, the above series of vowels in a direct order, and the same in an
inverse order, with intermediate positions giving no sound; and that this
cycle is repeated at equal lengths of the tube. A variety of other in-
teresting facts and principles were brought forward.

Art. XXX.— scientific INTELLIGENCE.
I. NATURAL PHILOSOPHY.

ASTKONOMY.

1. Observations on Encke's Periodical Comet. — This comet was disco-
vered on the 3d October by M. Pons at Florence. Our able countryman,
Mr Dunlop, <liscovered it at Makerston, in the observatory of Sir Thomas
Brisbane, on the 25th of October, and has observed it diligently since that
time.

2. Ephemeris of Encke's Cotnet continued.

io«o n- 1,.. A Declination Log. Dist.

. 1828. Right Ascen. ^^^^^^ froS Earth.

Nov. 15.3 329° 31' 18°25' 9.6942

17.3 327 24 17 20 9.6911

19.3 325 20 16 13 9.6881

21.3 323 17 15 5 9-6863

23.3 321 20 »13 57 9.6843

176

Scientific Intelligence.

1828.
Nov.

Dec.

Right Ascen.

Declination
North.

Log. Dist.
from Earth,

25.3

319° 24'

12° 48'

9.6826

27.3

317 29

11 38

9.6811

29.3

315 35

10 27

9.6796

1.3

313 41

9 14

9.6783

3.3

311 46

8 1

9.6751

5.3

309 50

G 45

9.6761

7.3

307 50

5 27

9.6751

9.3

305 48

4 7

9.6745

11.3

303 40

2 42

9.6742

13.3

301 27

1 14

South.

9,6744

15.3

299 7

0 20

9.6754

17.3

296 40

1 58

9.6774

19.3

294 5

3 42

9.6809

21.3

291 23

5 32

9.6863

23.3

288 39

7 28

9.6946

25.3

285 42

9 28

9.7046

27.3

282 49

11 31

9.7189

29.3

260 0

13 35

9.7360

31.3

277 22

15 38

9.7575

3, Comet of September 1827 and September 1720. — In No. xvi. p. 362
of this Journal, we gave M. Walz's elements of the comet of September
1827, compared with those of the comet of 1720.

The following elements of it, given by M. Nicolai, bring it still closer
to that of 1780.

Passage of Perihelion.

Mean time at Manheim, 1827, September, 11-69837

Perihelion distance, _ _ - 0.13750

Long, of Perihelion, - - 250° 58' 13" 4

Long, of Node, - - 149 39 4 3

Inclination of orbit, - - - 54 3 19 2
Motion retrograde.

4. Elements of the orbit of the Planet Juno. — In this Journal, No. xv.
p. 167, we have given the position of the planet at the time of her opposi-
tion on the 25th of March 1828.

The following elements of this planet have been given by Professor Ni-
colai of Manheim.

Epoch of her mean long, on the 25th March, - O**

At Manheim, - - - - 160° 29' 13".71

Mean daily tropical motion, - - 813''.69304

Long, of Perihelion, - - - 53°32'13".12

Eccentricity, - • - - 14° 52' 21 ".66

Meteorology. 177

Long, of Node, - - 171° 12' ll'Ms

Inclination of her orbit to the ecliptic, - 13 3 18 51

Long, of half the greater axis of her orbit, . 0.4264129

METEOROLOGY.

5. Captain Katers account of the luminous Zone of the Z9th September,
— At Chesfield Lodge, near Stevenage, Professor Moll and Captain Kater
observed at 8'^ 35' a luminous belt stretching from the eastern to the
western horizon. Its light was uniform, and greater than that of the
Milky Way, and its breadth throughout was 3° 45'; the stars were distinctly
seen through it. It covered the Pleiades, and seemed equidistant from «
Arietis and y Andromedse. It passed between a Aquilae and * Lyrae, at
the distance from « Aquilae of one- third or two-fifths of the distance be-
tween the stars. Its edges were upon /S and y Ophiuchi lower down, near
the western horizon. It was remarkably inflected to the N. and was soon
lost in the clouds. It seems to have occupied nearly a great circle, meet-
ing the horizon about the E. N. E. and W. by S. points. The height of the
centre of the most elevated part, appears to have been about 72°, so that it
must have been nearly in the plane of the dipping-needle, and nearly at
right angles to the magnetic meridian. It had no coruscations. At 8** 42'
mean time, the belt began to fade slowly from the E. to the W., and at
9h 22' no trace of it was perceptible. There was much wind from the
S. E. The barometer was 29.12 inches, and the thermometer 59°. Ches-
field Lodge is about 43" of time west of Greenwich, and in lat. 51° 56'
15" north.

6. Observations on the Luminous Arch at Islay-House, Islay. — On Mon-
day the 15th of September this interesting phenomenon was seen at Islay-
House. It appeared at ten minutes before nine o'clock, and crossed the
heavens in the form of a luminous arch, stretching from the south-east to
the north-west. It was pointed at each end, and broad at the centre, the
south-eastern extremity being rather fainter than that observed to the
south-west. Small radiations appeared to issue from it at the south-east ;
and the middle of the arch, where it was broadest, had an inclination to
the west, and was not so bright as the two ends. The south-eastern part
extended about one-third of the horizon beyond the Pleiades.

The arch remained stationary. When first seen, it was to the westward
of the Pleiades. At half-past ten it was much fainter, and the Pleiades
were considerably to the westward of the Arch.

In the south-east part of the horizon, there was seen at the same time a
most brilliant Aurora, changing from ro^e-colour to yellow and pale green.

7. Observations on the Luminous Arch near Edinburgh. — On the even-
ing of the 15th September, the Aurora Borealis began about 9** p. m. A
ray of light stretched from the western horizon with great brilliancy to-
wards the zenith, and formed an arch of great beauty, perhaps not inferior
to that of the 19th March 1825. About 9*^ 17' mean time it was in its
greatest beauty, and then rose from the constellation Serpens in the west,

VOL. I. NO. I. JAN. 1829. M

.178

Scientific Intelligence.

passing through et Lyra and « Cassiopeia, and terminated in tlie east ex-
actly at the Pleiades. By tracing this course on the globe, I found that its
direction was E. 23° N. and W. 24° S. which coincides with a direction at
right angles to the magnetic meridian. At the hour above-mentioned it
must have been almost precisely in the zenith of the place of observation.
Its motion was extremely slowly south in the same direction, but not
nearly so rapid as the arch I observed in .January 1826, and described
in my paper on the phenomena of 1826-7, published in this Journal.
The wind was W. the breadth of the arch was small, and its brilliancy
great at both ends, especially the west. It became more diffused and
fainter as it approached the zenith, where its breadth was about 5° or 6°,
and it did not conceal minute stars. At the western extremity it rendered
stars of the third magnitude nearly invisible. By half-past ten it had dis-
appeared. ^

8. Nuiice of the Mean Temperature of Falmouth and the vicinity. — In
the following tables are comprised the mean monthly results of observa-
tions made at Huel Gorland twice a- week ; at Dolcoath three times a- week ;
and in the neiglibourhood of Falmouth daily. The thermometers were
each four feet long, and their bulbs were sunk to the depth of three feet
under the surface, so that the variations from day to day, and even from
week to week, were frequently very inconsiderable. The first was in gra-
nite, and the two latter in clay-slate. The station at Falmouth is estimat-
ed at about 120 feet, and the two others at rather more than 300 feet
above the level of the sea.

Huel Gorland, Dolcoath, Falmouth.
1822. November, 53.°

47.2
43.5
43.55
44.6
47.55
51.3
53.8
54.75
56.1

December,

1823. January,

February,

March,

April,

May,

June,

52.74

53.6

July,

53.94

53.35

August,

55.3

66,6

September,

56.2

57.8

October,

53.7

52.7

November,

49.1

49.67

December,

46.

47.57

1824. January,

44.

44.44

February,

43.63

44.85

March,

42.8

44.08

April,

43 78

44.62

May,

46 69

47.85

September,

October,

Mean,

48.99

49.94

50.67

Meteorology — Electricity. 179

Giving fot- the mean of the three places, 49.86. The author considers the
mean temperature of the earth's surface in the vicinity of Falmouth to he
under 51°, and even less than 50° in a considerable portion of the mining
district of Corn\vall.--From Mr Fox's paper " on the Temperature of
Mines." Cornwall Geological Trans, vol iii.

9. Description of the luminous arch, as seen at Perth on the 15th October.
— On the evening of Monday last, an electro-magnetic arch of singular
beauty was distinctly visible here, for more than an hour, during the
greater part of which it underwent little or no change of appearance. It
was preceded by a vivid Aurora in the north, flitting along the skirts of
a dark cloud, which appeared and disappeared as the coruscations of light
darted in irregular vertical columns along its surface. A few minutes be-
fore 9 o'clock a bright pencil of luminous rays began to issue from the east-
ern side of the horizon, exactly on the N. E. by E. | E. point, and in a
short time it extended itself entirely across the heavens in the form of a
most magnificent arch. In the mid-heaven the breadth of the arch was
about 4 degrees, but it contracted gradually towards each extremity, and
at the opposite points where it intersected the horizon, it was barely visi-
ble,— an appearance which was owing to the greater distance of the lower
parts of the arch, which must have been about 750 miles from the observer,
on the supposition that the portion of it over his head was 60 or 70 miles
above the surface of the earth. At 9 o'clock the northern edge of the arch was
nearly in contact with the Pleiades, which were then about 10 degrees above
the horizon. Passing between Mirach and Almaac, it covered near thotzenith
the bright star in Cygnus, and stretching onward a little to the northward
of Vega, it touched Ras Alhagus in Ophiuchus, after which it intersected
the horizon, in the S W. by W. pohit. As it cut the horizon in two points
which were almost diametrically opposite, it had the appearance of being
nearly a great arch of the celestial sphere. It did not pass, however, through
the zenith of Perth, but through a point which was about 7 degrees south-
ward from it. The axis of the arch coincided very accurately, during the
whole time of its appearance, with the plane of the magnetic meridian,
thus indicating the intimate connection between this striking phenomenon,
and the electro-magnetic influence. r

10. Aurora Borealissesn at Perth on the29th October. — On Monday night,
between the hours of 10 and 11, the coruscations of the Aurora Borealis
were uncommonly vivid and changeful ; exhibiting themselves in broad
flashes of the most varied forms, which darted with inconceivable velocity
from the horizon to the zenith, and resembled rather an immense confla-
gration of the atmosphere, agitated by a violent tempest than the usual ap-
pearance of that flitting meteor.

ELECTRICITY.

11. Foerstemanns experiments on the conducting Power of different
Fluids for Voltaic Electricity. — The first column shows the specific gravity
of the fluid, the second the quantity of electricity which the fluid con-

1.12G

2.464

0.410

1.024

2.398

0.423

1.236

2.283

0.438

0.936

2.177

0.459

1.069

1.972

0.509

1.848

1.737

0.575

1.172

1.709

0.585

1.166

1.672

0.598

1.132

1.560

0.632

ISO Scientific Intelligence.

ducts in a given time, and the third the time required for the conduction
of equal quantities of electricity.

Muriatic acid,

Acetic acid.

Nitric acid.

Ammonia,

Solution of muriate of ammonia.

Sulphuric acid,

Solution of potash

Solution of common salt.

Solution of acetate of lead.

Distilled water, 1.000 1.000 1,000

II. NATURAL HISTORY.

MINERALOGY.

12. Notice of the produce of the Tin Mines of Cornwall and' Devon.'-'

Cornwall. Devon.

1822, 3127 tons. 10 tons of tin.

1823, 4010 21

1824, 4770 49

1825, 4100 70

1826, 4320 86

13. Of the Cornish Copper Mines.'-~

Average pro-
Tons of ore. duce of metal. Sold for
12 Months to 30th June 1823, 97.470 8| per cent. L.618,933
Do. 1824, J 02.200 7| 603,878
Do. 1825, 110.000 7| 743,253
Do. 1826, 118.768 7| 799,790
Do. 1827, 128.459 7| 755,358

14. Of the qtuLntity of Metallic Copper, the produce of the mines in Great
Britain and Ireland. —

Year to 30th June 1823. 1824. 1825. 1826. 1827.

Cornwall,

8070 tons.

8022 tons.

8417 tons.

9140 tons.

10450 toi

Devon,

510

451

654

482

424

Other parts of \
England, J

Anglesea,

740

726

758

735

Other parts of »
Wales, /

120

126

131

186

143

Scotland,

Ireland,

257

488

502

482

540

9715 9836 10350 11069 12381

From the Trans. Cornwall Geological Society, vol. iii.

Geology. 181

GEOLOGY.

. 15. General Summary of the Geology of India. By James Calder^
^sq, — The able memoir, of which the following observations form a part,
was read at the Asiatic Society of Calcutta on the 19th March 1828.

** Casting our eye over the map of India," says Mr Calder, " we are
struck with the grand and extensive mountain ranges which form the
principal boundaries. On the north we have the stupendous chain of the
Himalaya, extending from the confines of China to Cashmeer, and the
basin of the Oxus. That vast accumulation of sublime peaks, the pinna-
cles of our globe, is so extensive, that a plane, resting on elevations 21,000
feet, may be stretched, in one direction, as far as the Hindoo Cosh, for
upwards of 1000 miles, above which rise loftier summits, increasing in
height to nearly 6000 feet more. Primitive rocks alone have been found
to compose all that has yet been explored of the elevated portion of that
chain ; gneiss being, according to Captain Herbert, the predominating
rock, along with granite, mica, schist, hornblende, chlorite slate, and crys-
talline limestone. On these repose clay^slate and flinty-slate; and to-
wards the base we find sandstone composing the southern steps of the chain,
and forming the north-east barrier of the valley of the Jumna and Ganges,
by which, and the diluvial plains of Upper Hindoostan, this great zone is
separated from the mountain ranges of the Peninsula. The opposite or
southern boundary of this valley is of the same rock. Advancing to the
south, we come to three inferior mountain ranges, on which the Peninsula
table-land of India may be said to rest, or more properly, to which it owes
its peculiar form and outline. We may consider these ranges separately :
the western or Malabar, the eastern or Coromandel, and the central or
Vindya. Of these, the principal in elevation, and most remarkable in con-
tinuity of extent, is the western, which may be said to commence in Can-
deish, and runs along the Malabar coast, within a short distance of the
sea, in an unbroken chain to Cape Comorin, excepting where it is inter-
rupted near its southern extremity by the great chasm which forms the
valley of Coimbitoor. The direction of this chain deviates but little from
north and soutli, bending a little eastward towards its southern extremity.
Its elevation increases as it advances southward; the highest points beihg
probably between latitudes 10° and 15°, where the peaks of granite rise to
6000 feet and upwards.

The northern extremity of this range is entirely covered by part of the
extensive over-lying trap formation, to be more particularly described here-
after ; extending in this quarter from the sea-shore of the northern Con-
can to a considerable distance eastward, above and beyond the ghauts, as
far east and south as the river Tumboodra and Nagpore, These rocks as-
sume all the various forms of basaltic trap, passing from the columnar (of
which some fine specimens are to be seen opposite to Bassein, near Bombay)
into the globular, tabular, porphyritic, and amygdaloidal ; the two latter
containing an unusual abundance and interesting variety of included mi-
nerals peculiar to such rocks. The landscape here exhibits all the charac-
teristic features of basaltic countries ; the hills rising abruptly in perpen-
dicular masses of a tabular form, or in mural terraces piled on each other.

182 Scientific Intelligence.

and frequently separated by immense ravines ; the whole clothed with lux-
uriant forests of teak and other trees, producing some of the most beauti-
ful and romantic scenery of India. The elevation of this part of the range
seldom exceeds 3000 feet ; but advancing to the south, its height gradual-
ly increases, and the granite rocks begin to re-appear, continuing to form
the summit of the chain with little interruption all the way to Cape Co-
raorin. In nearly the same parallel of latitude, this trap formation is ob-
gerved to terminate also on the sea-coast, a little to the north of Fort Vic-
toria, or Bancoote, where it is succeeded by the iron-clay, or laterite (a
contemporaneous rock associating with trap,) which from thence extends
as the overlying rock, with little interruption, to the extremity of the Pe-
ninsula, covering the base of the mountains, and the whole of the narrow
belt of low-land that separates them from the sea, exhibiting a succession
of low rounded hills and undulations, and reposing on the primitive rocks,
which occasionally protrude above the surface, as at Malwar, Melundy,
Calicut, and some other points, where granite, for a short space, becomes
the surface rock. From the main-land the laterite passes over into Cey-
lon, where it re-appears under the name of kubook, and forms a similar de-
posit of some extent on the shore of that island. Passing onward from the
western or Malabar coast, round the extremity of the Peninsula, we leave
this extensive iron-clay formation behind, and crossing the granitic plains
of Travancore, which are strewed with enormous blocks of primitive rocks,
we arrive at the termination of the chain. Here the mountain ranges,
which support the central table-land, meet from both sides of the Penin-
sula, and converge to a point, within about thirty miles of Cape Comorin,
ending abruptly in a bluff granite peak of about 2000 feet high, from the
base of which a low range of similar rocks, forming a natural barrier to the
kingdom of Travancore, extends southward to the sea. The whole of this
western mountain range, and the narrow coast which lines its base, is re-
markable for the absence of rivers, and vallies of denudation, and conse-
quently of alluvial plains or deposits. The abrupt precipitous sides of the
mountains, rising almost perpendicularly from the sea, are nevertheless
covered, in general, by forests of the tallest trees and impenetrable jungles,
which admit of gaining but a vague and scanty knowledge of the mineral
treasures with which they probably abound, if we might be allowed to
draw inferences from the striking analogy in geological feature and out-
line between the mountain ranges and western coast of the South Ameri-
can continent and that just described, in some parts of which traces of
copper, gold, silver, and other ores have been found.

Proceeding on to the eastern side of the Peninsula, and northward along
the foot of the mountains, we observe a country differing very considera-
bly from the Malabar coast in appearance and geological character. The
plains of the Cororaandel coast form rather a broad though unequal belt of
low land between the mountains and the sea, exliibiting the alluvial deposits
of nearly all the rivers and streams that descend from the southern portion
of the table-land. The mountain chain that forms the eastern boundary
of the Peninsula, after a short nprtherly course from Cape Comorin, be-
gins to diverge to the east, near where the great valley of Coimbitoor (al-

' Geology, J 83

ready mentioned) interrupts its continuity. From thence it breaks into a
succession of parallel ranges, inferior in elevation and in unbroken conti-
nuity, to the western chain, and in the further progress northward after
breaking off into subordinate hilly ranges, occupying a wide tract of unex-
plored country, and affording vallies for the passage of the great rivers that
drain nearly all the waters of the Peninsula into the bay of Bengal. This
eastern range may be said to terminate at the same latitude as that of the
commencement of the western. Granite rocks, and principally sienite,
seem to form the basis of the whole of these eastern ranges, appearing at
most of the accessible summits from Cape Coraorin to Hydrabad. Gneiss
and mica-slate, that form the sides and base of the mountains, are some-
times seen, as also clay-slate, hornblende, slate, flinty-slate, chlorite, and
mica-slate, and primitive or crystalline limestones, affording, in some
places, marbles of various colours, as in the district of Tennivelly, where
also granite appears rising above the surface, in remarkably globular con-
cretions, and in perfectly stratified masses, forming low detached hills near
Palemcotta, the strata of which dip at an angle of about 45° to the south-
west. Partial deposits too of^ overlying rocks exist in this district, and of the
black cotton soil, which is supposed to be produced by the debris of trap.
In the neighbourhood of Pondicherry there are beds of compact shelly
limestone, and some remarkable siliceous petrefactions, chiefly of the ta-
marind tree, which have never yet been well described. The beds of the
Cavery, or rather the alluvial deposits in the vicinity of Trichinopoly,
produce a variety of gems, corresponding to those of Gey Ion. In general,
however, the surface of the level country, as far north as the Pennar river,
seems to consist of the debris of granite rocks, and plains of marine sand,
probably left by the retreat of the sea ; with occasional fresh water alluvial
deposits, and partial beds of iron-clay arid detached masses of the overly-
ing class. In approaching the Pennar river, the iron-clay formation ex-
pands over a larger surface, and clay, slate, and sandstone begin to appear.
On the hills behind Nellore are found specimens of a very rich copper ore,
yielding from fifty to sixty per cent, of pure metal, according to Dr Heyne,
besides argentiferous galena.

It is to the observations of Drs Heyne and Voysey that we owe all the
information we yet possess of the vallies of the Pennar, the Kistna, and the
Godavery rivers. This interesting tract of country is not more remarka-
ble, as the ancient source of the most valuable productions of the mineral
kingdom, being the repository of the Golconda diamonds, than for the
extraordinary geological features which it presents. The Nella Malla
range of mountains, in which the diamond breccia is found, is described,
by Dr Voysey, as exhibiting a geological structure that cannot easily be
explained by either the Huttonian or Wernerian theorists ; the different
rocks being so mixed together with regard to order of position, each in its
turn being uppermost, that it is difficult to give a name to the formation
that will apply in all cases. The clay-slate formation is the name he has
adopted, under which are included clay-slate, every variety of slaty lime-
stone, sandstone, quartz rock, sandstone breccia, flinty-slate, hornstone
slate, and a tufaceous limestone, containing imbedded in it fragments.

184 Scientific InteWgence,

round and angular, of all these rocks, all passing into each other by such
insensible gradations, as well as by abrupt transitions, that they defy ar-
rangement, and render description useless. It is bounded on all sides, how-
ever, by granite, which passes under it and forms its basis ; some elevated
points, such as Naggery Nose, having only their upper third composed of
sandstone and quartz, while the basis is of granite.

The rocks above enumerated, with the addition of the iron-clay and ba-
saltic rocks, occupy extensive portions of the valleys of the Kistna and Go-
davery, covered in some places by the black trap soil. The granite rocks,
on which they rest, are often penetrated and apparently heaved up by in-
jected veins or masses of trap and dikes of green-stone. Mr Calder hopes
soon to be enabled to lay before the Society a detailed description of the
curious formations, accompanied by sections of the strata, between Madras
and Hydrabad. The waters of the Kistna and Godavery expand as they
approach the sea, dividing into numerous branches, and depositing their
alluvial contents during inundations over a considerable extent of land
bordering the coast. The largest portion of deposits consists of decayed
vegetable matter, yielded by the extensive forests through which they
flow ; and here may be noticed the characteristic difference that marks the
alluvial deposits of the principal river of the south — the Cauvery. This
river, flowing in a long course through the Mysore country, over an ex-
tensive and generally barren surface of granitic and sienitic rocks, with
scarcely any woods or jungle on its banks, brings down little or none of
decayed vegetable alluvium ,' but a rich yellow clay, produced by the fel-
spar, which predominates in the granites of Mysore and the south, and
which, mixed with carbonate of lime, renders the plains of Tanjore by far
the most fertile portion of the south of India. Passing on to Vizagapatam
and Ganjara, the granite rocks appear occasionally covered by laterite.
The granite of Vizagapatam assumes a new and singular appearan ce, being
small-grained and intimately intermixed with amorphous or uncrystalliz-
ed garnets, in round grains or specks. This peculiar rock passes into the
province of Cuttack. The only information we possess regarding that in-
teresting district is derived from Mr Stirling's valuable paper in the last
volume of the Asiatic Society's Researches. The rocks of the granite class
form the basis and predominant elevations of this district ; they are re-
markable for their resemblance to sandstone, and abounding in imperfect-
ly formed garnets, disseminated throughout with veins of steatite. Here
too traces of coal have recently been discovered, which is likely to be pro-
ductive, and gold is frequently found in the sands of the Mahanuddee, pro-
bably from the valley of Sumbulpore. We next trace the laterite, increas-
ing in extent all the way to Midnapore, and thence continuing northwards
by Bissuniwre and fiancorah to Beerboom.

16. Organic Remains at Clash-bennie Quarry in Forfarshire, — Specimens
of these interesting products of former ages have lately been found in
Clash-bennie quarry, which is situated on the south-west boundary of the
parish of Enrol, and on the left bank of the Tay. These specimens have
at first sight very much the appearance of shells, but on closer inspec-

Geology^^Botany. 185

1;ion, they reseinbk more nearly the scales of a fish. They vary consider-
ably in size, from being an inch to two inches in length, from a half to an
inch and a half in breadth, and from a tenth to an eighth of an inch nearly
in thickness. Their structure is entire. In some of thera the portion of
the scale which enters the cuticle, and which resembles so much that of
the human nail, is perfect, preserving all its original smoothness; in others,
the diflPerent plates of which the scales are composed can be distinctly tra-
ced ; and in some specimens, where a number of the scales are conjoined,
they are imbricated as when in the living animal, like the slate of the
house. No entire skeleton has yet been found, although there is one spe-
cimen which bears a very strong resemblance to the shoulder of a fish, and
another of very small dimensions, can, with a little help from the imagina-
tion, be made out as an impression of the whole animal. This quarry has
now been opened for several years past ; and it is to be lamented that no
amateur of the science should have been made acquainted with the fact of
the imbedded relics, until within these few weeks, as, from their great
abundance (being disseminated thiough the whole rock) many of the
finest specimens must have been destroyed or fallen into the hands of indi-
viduals incapable of estimating their value. What particularly enhances
the value of this discovery is, that the rock in which it has been made is
the old red sandstone, which belongs to that series and geological epoch ia
which so few organic remains have hitherto been found, and from which,
we first date the existence of the vertebral animals. The prodigious anti-
quity of this rock, and of course of the animals which lie entombed in it,
may be estimated from the fact, that the old red sandstone invariably dips
beneath the masses of trap which constitute the hills around us, and forms
the basis on which rests the coal and limestone of all the Scottish districts.

17. Fossil, 7^wr</e.— Another of those interesting productions of nature, the
fossil organic remains of a sea turtle, has been discovered, and is now in
possession of Mr Deck of Cambridge. It is imbedded in a mass of septa-
ria, weighing upwards of 150 pounds, with two fine specimens of fossil
wood, and exhibits in a most perfect state this singular animal of a former
world, once undoubtedly an inhabitant of our shores. It was obtained
in dredging for cement-stone, about five miles from Harwich, in three fa-
thoms water, and, as a mass of stone, been used for some time as a step-
ping-block, from which humble station it was accidentally rescued by its
possessor for the admiration of the virtuosi.

BOTANY.

18. Account of the Sensitive Properties of the Stylidium graminifolia. — This
species, in common with several others, possesses a singular irritability of
the column, which,''in its natural state, is bent over the reflexed lip of the
corolla, between the two upright appendices, so as to bring the anthers and
stigma nearly in contact with the gerinen. When slightly touched near
the base, the column suddenly springs up, carrying the anthers and stigma
with a sudden jerk over to the opposite side of the flower. When left
quiet, after a short time, it gradually resumes its former position, but is

1B6 Scientific Intelligence,

ready to spring again when exposed to any sudden irritation ; though when
irritated too frequently the force of each successive spring becomes dimi-
nished. The use of this curious mechanism does not appear to he very
evident. It is supposed to be intended as a means of assisting the plant in
dispersing its pollen, the better to insure a fertilization of the ovary, which,
notwithstanding a close approximation of anthers and stigma, is perhaps
impossible to be effected by its own individual anthers, from the stigma not
becoming exposed till after the bursting of the latter. — N- S. Walts Paper,

19. Singular phenomenon inihe Sensitive Plant. — Mr Burnet and Mr Mayo
have found that at the moment the expansion at the foot of the leaflets or
other parts of the sensitive plant was touched, so as to occasion the motion
of the plant, it changed colour. They also found that when a sensitive
plant had been made to droop, the part in which the moving power resides
is blackened, so as to absorb the light of the sun, the restoration of the plant
to its natural state is much longer in taking place.

III. GENERAL SCIENCE.

20. Notice of the Saline Lake of Loonar in Berar. — This curious lake is
contained in a sort of cauldron of rocks amidst a pleasing landscape, and
is of course the object of superstition. The taste of the water is uncom-
monly brackish. Mr Alexander, who describes it, found by a rough analysis
that 100 parts contains

Muriate of soda, 20 parts

Muriate of Hme, 10

Muriate of magnesia, 6

The principal purpose to which the sediment of the water is applied is
cleansing the shawls of Cashmere. It is also used as an ingredient in the
alkaline cake of the Mussulmans. — Trans, Lit. Soc. Madras y Part i.

21, Inflammable Gas after boring for 5a/^— While boring for salt at Rocky
Hill in Ohio, about one mile and a-half from Lake Erie, the auger fell
when it reached the depth of 197 feet, and salt water spouted out for se*
veral hours When the water was discharged, great volumes of inflam-
mable air continued for a long time to issue from the aperture, and form-
ed a cloud ; and in consequence of its having been set on fire by the fires
in the workshops, it consumed and destroyed every thing in the neigh-
bourhood.— Trans. Phil. Soc» New York.

22. Bequest to Science by Dr Wollaston and Mr Davies Gilbert. — In
order to promote the interests of the Royal Society by providing a fund
which may render it less necessary to elect members more for the sake of
the revenue they furnish than of their scientific attainments, Dr Wollas-
ton has bequeathed L. 2000 to the Society, and its eminent President, Mr
Davies Gilbert, has added L. 1000 for the same purpose.

23. Adjudication of a Royal Medal to Dr Wollaston. — On the 1st De-
cember the Royal Society adjudged one of the lloyal Medals to Dr Wollas-

List of Scottish Patents.

187

ton for his paper on the Processes and Manipulations by which he prepared
platinum and the other metals which accompany it.

24. Adjudication of a Royal Medal to M. ETicke.—The Royal Society
has adjudged the other Royal Medal to M. Encke for his determination of
the orbit of the interesting periodical comet which bears his name.

25. Obituary of Members of the Royal Society of London. The loss
which the Royal Society of London has sustained since last year is un-
usually severe. The following is a list of the Members which it has lost :

Professor Dugald Stewart, Mr Mills,

Sir James Edward Smith, Dr J. Mervin North,

Archdeacon Coxe, Mr Planu,

Mr William PhiUips, Dr George Pearson,

Major Denham, Professor Woodhouse,

Reverend Professor NicoU, M. Thunberg.

26. Twa Royal Medals established for the Society of Antiquaries. — At the
second meeting of the Society on the 27th November, Mr Hallam announ-
ced that his Majesty had signified to the President and Council his inten-
tion of conferring two Gold Medals annually, of the value of Fifty Guineas
each, for the two best papers on Antiquity which may be presented to the
Society.

Aet. XXXI.— LIST OF PATENTS GRANTED IN SCOTLAND
SINCE SEPTEMBER 9, 1828.

24. September 9. For a New mode of communicating Heat to various
Purposes. To Joshua Taylor Beale, county of Middlesex.

25. September 22. For a New and Improved Method of applying Iron
in the Sheathing of Ships and other Vessels, and of applying Iron Bolts,
Spikes, Nails, Pintals, Braces, and other fastenings used in the construction
of Ships and other Vessels. To Granville Sharp Pattison, county
of Middlesex.

26. October 1. For the Improved application of Air to produce Heat in
Fires, Forges, and Furnaces, where Bellows or other Blowing Apparatus
are required. To James Beaumont Neilson, county of Lanark.

27. October 6. For a New Method of propeUing Vessels, which Method
is also applicable to other Purposes. To Andrew Motz Skene, Esq.
county of Middlesex.

28. October 6. For an Improved Cartridge for Sporting Purposes. To
Edward FoRBhS Orson, county of Middlesex. .

29. October 6. For certain Improvements in Machinery for Hackling,
Dressing, or Combing Flax, Hemp, Tow, and other Fibrous Materials. To
Peter Taylor, county of Lancaster.

188 Celestial Phenomena, January 18^9 — April 1829.

30. October 9. For an Improvement in the Waterproof Stiffening for
Hats. To Joseph Blades, county of Surrey.

31. November 29. For a Method of, and an Apparatus for, generating
Steam and various Gasses'to produce Motive Power, and for other Useful
Purposes. To Samuel Hall, county of Nottingham.

32. December 6. For certain Improvements in the Method of manufac-
turing and cutting Paper by means of Machinery. To John Dickinson,
county of Hertford.

Art. XXXII.— celestial PHENOMENA,

From January 1st, to April 1st, 1829. Adapted to the Meridian of Greene
wick. Apparent Time, excepting the Eclipses of Jupiter's Satellites which
are given in Mean Time.

N. B. — ^The day begins at noon, and the conjunctions of the Moon and
Stars are given in Right Ascension.

15
15
19

1 12

20
3
6
6

9 18

10 8

11 11

11 19

12 1

13 17

19 17

20 10

20 14

21 18

22 1
27 17

27 18

28 17
28 18

28 21

29 5
29 18

29 21

30 15

JANUARY.

31. S.

12 20p c5>'=^])Cl'N.
3 25>c59^ })70'S.

52 0 New Moon.

19 34 J ci yS 1^ ]) 6' N.

28 9 p c5 3 C55 5 34' N.

13 45 im. II. Sat ^

? d 2 Ophiuchi.

16 23 J 3 9 K )) 21' S.
18 H First Quarter.

38 55 p c5 • K 1 25' N.

16 § Sup. c5 0

1 34 P (5 1 d^ b ]) 3' S.

33 18 5 c5 2 J" a 5 4' S.

17 O f'"U Moon.
37 8 Em. III. Sat y.

44 0 enters 555

49 6 ^ c$ 2 A 20 ]) 49' N.

45 b^0

33 ll| d'^'i^ ])30'N.

21 (T Last Quarter.

12 2 Ira. I. Sat. 11

12 7 ]) c5 > =^ D 55' S.

18 31 J c5 S :£i= 5 19' N.

9d«^n

31 13 ^ 3 <J> Opli- D 57' S.

FEBRUARY.

21 3C )) (5 ^ VS D 6' N.

31 0 New Moon.

32 40 }) c5 fi CK D 27' N.

18
7

25
0

6^X ])36'S.

6 <?

d 0 K D 9' N.

d^c»
^ First Quarter.
Im. II. Sat 11

' 61'^ ^ D 9' s.

d 2 «r « ]) 65' N.
d * « D 70' N.
Greatest Elong.
Im. I. Sat V

?d¥

d A « 25 ]) 70^ N.
d 2 « 2S » 47' N.
df <a )45'S.

d " <a ) 2' N.

d 5^ ^ ) 32' N.

Full Moon.

enters K
Stationary.

dj^ )70'S.

dfi n )

d fl nje ) 04' s.

d « T1J ) 48' S.
c5 > :^ ) 43' S.
d fl ^ ) 31' N.
d <P Oph. ) 46' S.
Last Quarter.
d0

MARCH.

10) d/2 n )H'N.

5?Em.|"^-^-y
48 ) (5 6 as ) 27' N.

Celestial Phenomena, January 1829 — April 1829. 189

4
5

7
7
7
8
10
10
10
11
13
14
15
15
15
10
16
17
19
20

24
51

0 Full Moon.
15 ) d ^ K ) 43' S.
56 Em. II. Sat. 7/
7 ) 6 0 K ) 1' N.
m. I. Sat. y.
C^ 1 cf « ) 26' S.
3 2 «f « ) 18' S.

5 Aid. ) 55' N.
First Quarter.
Stationary.
1. II. Sat. V
c5 1 «t as ) 65' N.

^ 2 a OS ) 43' N.
d I <a ) 48' S.

6 0 Q. ) 1' s.
C5 «• ^ ) 30' N.
d -r 51 ) 70' S.

Full Moon.

D. H.
20 0

20 Moon Eclipsed, invisible at Green-
wich.

11 ;

)

'sN

limb.

Begins.

Ecliptic ^
15 Middle.
30 End.
29 Digits Eclipsed on the

d«
)d>

Im. I. Sat. 11

) d <? Oph. ) 35' N.

( Last Quarter.

P Greatest Elong.

f) Stationary.

) d /S n ) 14' N.

y. Stationary.
33 ) d 9 «s ) 28' N.
43 Im. I. Sat. 1/

Times of the Planets passing the Meridian.
JANUARY.

Mercury.

Venus.

Mars.

Jupiter.

Saturn.

Georg]

an.

D. h.

h '

I 23

4 46

7 23

4 35

13 0

4 24

19 0

4 14

25 0

4 4

FEBRUARY.

1 0

3 54

7 1

3 45

13 1

3 37

19 0

3 29

25 0

3 22

MARCH.

1 23

3 18

7 23

3 11

13 22

3 5

19 22

3 0

25 22

2 54

Declination of the Planets,

JANUARY.

Mercury.

Venus.

Mars.

Jupit

ST.

Saturn.

Georgiai

D. "

o /

O '

o /

1 24 36 S.

19 56 S.

3 23 S.

20 22 S.

20 ON.

20 288.

7 24 28

21 11

1 34 S.

20 35

20 7

20 20

13 23 30

0 14N.

20 46

20 14

20 19

19 21

22 37

2 I

20 57

20 21

20 14

25 18 44

22 43

3 47

21 €

20 28

20 10

190 Mr MarshalPs Meteorological Observations

FEBRUARY.

e /

o '

0 / o /

o /

14 18 S.

22 20 S.

6 48N. 21 16 S.

20 36N.

4S.

9 54

21 34

7 30 21 24

20 43

5 47

20 25

9 9 21 30

20 49

3 19

18 59

10 46 21 36

20 54

3 23

17 4

12 18 21 40
MARCH.

20 59

4 50 S.

15 34 S.

13 18N. 21 43 S.

21 2N.

43 S.

7 40

13 21

14 44 21 46

21 5

9 46

10 50

16 6 21 48

21 8

10 32

8 9

17 22 21 50

21 10

10 2

5 19

18 33 21 51

21 11

The preceding numbers will enable any person to find the positions of
the planets, to lay them down upon a celestial globe, and to determine their
times of rising and setting.

Art. XXXIII. — Summary of Meteorological Observations made at Kendal
in September, October, and November 1828. By Mr Samuel Marshall.
Communicated by the Author.

State of the Barometer, Thermometer, &^c. in Kendal for September 1828

Barometer. Inches.

Maximum on the 16th, ... 30.40

Minimum on the 12th, . . - - 29.16

Mean height, . . . . 29.78

Thermometer.

Maximum on the 9th, - - - 73"

Minimum on the IGth, - - - - 33.5*

Mean height, .... . 55.05*
Quantity of rain, 4.497 inches.
Number of rainy days, 13.
Prevalent wind, west.

For the first week in this month, the weather was as fine as that which
we had at the latter part of last month, aflPording abundant opportunity to
conclude the labours of the harvest in this district. We then had a suc-
cession of wet days till the 14th, and again a portion of remarkably fine,
clear weather to the 23d, since which time we had heavy rain very fre-
quently. The temperature has been very variable. On the 8th the ther-
mometer stood at 73°, whilst on the 13th it did not attain a higher alti-
tude than 51° during the day. On the 24th we had sudden, violent squalls
of wind, such as are usually prevalent, about the time of the equinoxes,
and which have occurred almost daily since that period. The changes
from a clear to a cloudy sky have been very sudden in that period, the sky
being remarkably clear at times, and in a few minutes, completely over-
cast, and attended with sudden squalls and heavy rain.

made at Kendal in Sept. Oct. and Nov, 1828. 191

October.

Barometer. Inches.

Maximum on the 29th, - _ - 30.40

Minimum on the 6th, - - - 28.95

Mean height, - n - 29.86

Thermometer.
Maximum on the 14th, - - - - 60.5'

Minimum on the 29th, - . - - - 28.5°

Mean height, - , > - - 47.86°

Quantity of rain, 4.916 inches.
Number of rainy days, 13.
Prevalent wind, west.

During the first week of October we had very heavy rain and high
winds, since which time there has generally been remarkably fine weather.
Almost all the rain measured this month fell during the first eight days.
The barometer is seldom so high at this season as it has been during this
month. For fifteen days it was above 30 inches, which occasions the mean
to exceed what is usual. The weather has been generally very open, and
we have had but three nights of frost. No Aurora Borealis has been
noticed, but some thunder and lightning occasionally at the beginning
of the month. The autumnal tints did not appear much till the latter
part,

November.

Barometer. Inches.

Maximum on the 3d, - - . 30.18

Minimum on the I6th - - - 29.09

Mean height, ... . 29.65

Thermometer.
Maximum on the 29th, , . . 64.5*

Minimum on the 12th, - - - . 26*

Mean height, - - - , 44.64*»

Quantity of rain, 4.786 inches
Number of rainy days, 17^
Prevalent wind, west.

This month has, towards the latter part especially, fully redeemed its
ancient character of gloominess. In the early part there were several
clear and fine days. The mountains in the neighbourhood, even those of
the lowest elevation, were seen on the 10th, for the first time this season,
clothed in their winter garb of snow. On the evening of the 19th about
\ past 6 o'clock, a portion of a lunar rainbow was seen, though nearly co-
lourless. No Aurora Borealis has been observed during the month. Though
the weather has been dull, and from the 12th to the end of the month,
there was frequent rain, the barometer has mostly been high. Before the
12th but .087 inch fell. The mean temperature of this month is rarely so
high as 44.64,° and there have been but two frosty nights. The quantity
of rain, calculating to the end of November, falls short of the annual
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THE

EDINBURGH
JOURNAL OF SCIENCE,

Art. I. — Biographical STcetch of the late Dugald Stewart^
Esq. F. R. SS. Lond. and Ed.

Although Mr Dugald Stewart was not the Author of any
express work directly connected with the mathematical or
physical sciences, yet he has been pronounced by a competent
judge* to have been " a distinguished writer in the higher de-
partments of Mathematics;" and from this cause, as well as from
the happy application which he made of his mathematical and
physical knowledge to illustrate the philosophy of the human
mind, we have considered it not unappropriate, in the pages
of a scientific Journal, to record the labours of a man, who,
while he was one of the brightest ornaments of his own coun-
try, contributed so powerfully to advance the intellectual and
moral interests of his species.

Dugald Stewart was born at Edinburgh on the 2Sd No-
vember 1753, and was the only son who survived the age
of infancy of the celebrated Dr Matthew Stewart, Professor of
Mathematics in the College of Edinburgh, and Miss Stewart,
daughter of Mr A. Stewart, Writer to the Signet. When a child,
his health was feeble and precarious, and it was only by the
greatest care that his parents succeeded in re-establishing it.
At the age of seven he went to the High School, where his
talents were favourably displayed, and after completing the usual
routine of instruction at that academy, he was admitted a
student in the University. Under the roof of his father, he

* Davies Gilbert, Esq. M, P. the distinguished President of the Royal
Society of London.

VOL. X. NO. II. APRIL 1829. N

J 94 Biographical Sketch of the late Dugald Stewart ^ Esq.

was early initiated into geometry and algebra; but the pecu-
liar bias of his mind was exhibited during his attendance on
the lectures of Dr Stevenson, then Professor of Logic, and of
the celebrated Dr Adam Ferguson, who filled with so much
talent the chair of Moral Philosophy. It was this circum-
stance, no doubt, that induced his father to send him at the
age of eighteen to the University of Glasgow, to attend the
lectures of Dr Reid, who was then sustaining, single-handed,
the honour of that seat of learning, which had in the course
of a few years been deprived of the services of Dr Robert
Simson, Dr Adam Smith, and Dr Black. In the session of
1771-1772, he attended a course of Dr Reid*s lectures, and
was thus enabled to prosecute, under his great master, that im-
portant science which he was destined to illustrate and extend.
The progress which he here made in his metaphysical studies
was proportioned to the ardour with which he devoted him-
self to the subject ; and, not content with listening merely to
the instructions of his master, or with the speculations of his
leisure hours, he composed during the session the admirable
Essay on Dreaming, which he afterwards published in the first
volume of his Philosophy of the Human Mind.

The health of his father had been for some time declining,
and in the autumn of 1771 it had become so precarious, that
Mr Stewart was called upon to prepare for teaching the mathe-
matical classes during the ensuing session. This duty, which
devolved upon him at the age of nineteen, he discharged with
great credit to himself, and, notwithstanding the high reputa-
tion of his father, the great success of his son brought an ad-
ditional number of students to the class.

In the year 1774, when he had reached his twenty-first year,
he was appointed assistant and successor to his father, — a situa-
tion which he continued to fill till the death of Dr Stewart
in 1785.

In the year 1778, when Dr Adam Ferguson was appointed
secretary to the commissioners for quieting the disorders which
had broken out in America, Mr Stewart undertook to supply
his place during the session of that year ; and this unexpected
occupation was the more severe, as he had previously pledged
himself to deliver a course of lectures on astronomy, in addi-

Biographical Sketch of the late Dugald Stewart, Esq. 195

tion to the usual labours of his two mathematical courses.
Three days after he had undertaken this difficult task, Mr
Stewart commenced his course of Ethics, and with no other
preparation but that which he was able to make in the morning,
he delivered a course of extempore lectures, which displayed
in a remarkable degree the vigour of his mind, and the extent
of his general information. Before the close of the session, his
health had obviously suffered from the bodily as well as the
mental fatigues to which he had been exposed, and such was
the degree of his exhaustion, that it was necessary to lift him
into the carriage when he set off for London at the close of
the session.

The reputation of Mr Stewart had now become so great,
that several of the English and Scottish nobility were desirous
of placing their sons under his superintendence ; and he ac-
cordingly, in 1780, agreed to receive some pupils into his
house. Among these were the late Marquis of Lothian, the
late Lord Bel haven, Basil Lord Daer, the late Lord Powers-
court, Alexander Muir Mackenzie, Esq. of Delvin, and the
late Mr Henry Glassford. He accompanied the Marquis of
Lothian to Paris in 178S, and on his return from the Conti-
nent, in the autumn of the same year, he married Miss Banna-
tine, daughter of Neil Bannatine, Esq. a merchant in Glas-
gow, by whom he had a son, the present Lieutenant-Colonel
Matthew Stewart, who inherits no small sHare of the talents
and acuteness of his father.

In consequence of the failure of Dr Ferguson's health in
1784, he resolved upon giving up the duties of a public lec-
turer, and an arrangement was made, by which Mr Stewart
should receive the moral J)hilosophy class, while Dr Ferguson
should be conjoined in the professorsliip of mathematics with
Professor Playfair, and thus retain the larger salary which was
attached to that chair. In 1 787, Mr Stewart was left a widower,
and in the following summer he accompanied the late Mr Ram-
say of Barnton on a visit to the Continent.
i/ In the year 1790 he married Miss Cranstoun, (the youngest
daughter of the Honourable George Cranstoun,) a lady of con-
genial sentiment and talent, who contributed greatly to the
(happiness of his future years. In the tranquillity of domestic

196 Biagraphkal Sketch of the late Dugald Stewart, Esq.

life, so favourable to the pursuits of science, Mr Stewart seems
to have begun with earnestness to prepare for the press the
first of that series of works by which he has been so highly
distinguished. In 1792 he pubhshed the first volume of his
Elements of' the Philosophy of the Human Mind. In this work
he has stripped the science of the Human Mind of much of that
mystery and paradox in which it had been involved ; and while
he has treated its most important and difficult topics with all
the depth and clearness of mathematical talent, he has, at the
same time, enriched his speculations with the stores of his va-
ried learning, and adorned them with all the elegancies of his
classical taste. This volume contains a review of the Intellec-
tual Powers of Man. On many important points, Mr Stewart's
views necessarily coincided with those of his illustrious master ;
but while he treated the opinions of Dr Reid with all the
veneration of a disciple, he never scrupled to examine them
with the freedom of an equal, and to advocate opposite opi-
nions, or strike into a new train of thought, into which he had
been led by a more profound or a more ingenious investigation.
In this, as well as the other two volumes of his work, Mr
Stewart's great aim was to vindicate the principles of human
knowledge against the attacks of modern sceptics, and to lay a
solid foundation for a rational system of logic.

This first volume of Mr Stewart's work did not excite that
notice to which its own merit and the high reputation of its
author unquestionably entitled it. The Philosophy of the
Mind was then a subject of comparatively little interest, and
though divested of its usual repulsive aspect, it was not consi-
dered, as it is now, a necessary branch of a polite education.
The long interval of twenty-one years, which elapsed between
the publication of the first and the second volume, and the
publication of his volume of Philosophical Essays at an inter-
mediate period, may afford us some reason for believing that
Mr Stewart had abandoned the prosecution of his plan.

The continuity of his studies was, indeed, interrupted by a
series of biographical works, which almost necessarily devolved
upon him. The first of these was, An Account of the Life and
Writings of Dr Adam Smithy the celebrated author of the
Wealth of Nations. This memoir, which occupies 82 quarto

Biographical Sketch of the late Dugahl Stetvart^ Esq. 197

pages, was read before the Royal Society of Edinburgh on the
28th January and the 18th March 1793, and is pubhshed in
the third volume of their Transactions. It forms one of the
finest examples of biographical composition, and, independent
of the value which it derives from its luminous exposition of
the principles of Dr Smith's philosophy, it is rendered inte-
resting by the numerous anecdotes which it contains of the
great men which had a short time before adorned the literary
history of Scotland.

At the request, we believe, of Dr Robertson himself, made
a short time before his death, Mr Stewart undertook to draw
up an account of the life and writings of that illustrious his-
torian. It was read before the Royal Society of Edinburgh
in March 1796, and was afterwards published in a separate
volume in 1801. To the memory of Dr Reid, Mr Stewart
felt it his duty to pay the like homage, and he accordingly com-
pleted, in 1802, his account of the life and writings of that
eminent metaphysician. , * i

In the year 1796, Mr Stewart was again induced to receive
a few pupils into his house, and at this time the present Earl
of Dudley, the Earl of Warwick, the late Lord Ashburton,
the son of Mr Dunning, Lord Palmerston, his brother the Ho-
nourable Mr Temple, and Mr Sullivan, the present Under Se-
cretary of War, were placed under his care. The Marquis of
Lansdown, though not under Mr Stewart's superintendence,
was at this time studying in Edinburgh, and was honoured
with Mr Stewart's particular regard. Their friendship conti-
nued unabated, and Mr Stewart had the happiness of seeing
theMarquis of Lansdown, Lord Dudley, and Lord Palmerston,
members of the same Cabinet. Mr Brougham and Mr Horner
were at the same time two of the public pupils of Mr Stewart.

Mr Stewart had been long desirous to deliver a course of
lectures on Political Economy, but it was generally understood
that he was deterred from carrying this design into effect by
the peculiar character of the times in which he lived. In 1800,
however, when the effervescence of political speculation had sub-
sided, he gave a course of lectures on Political Economy, but
we believe they were not repeated more than once in subse-
quent sessions.

198 Biographical Sketch of the late Dugald Stewart, Esq.

In 1806, when an accidental circumstance led the English
and the French Governments into an amicable correspondence,
the Earl of Lauderdale was sent to Paris to adjust the preli-
minaries of a general peace. This nobleman requested Mr
Stewart to accompany him as a friend, and they accordingly
spent some time in the French metropolis. Here Mr Stewart
had an opportunity of seeing many of the eminent individuals
with whom he had formed an acquaintance previous to the
Revolution, and of being introduced to some of the great men
who then adorned the science and literature of France.

While individuals of inferior talent, and of much inferior
claims, had received the most substantial rewards for their
services, it had been long felt that a philosopher like Mr Stew-
art, who derived so small an income from his professional oc-
cupations, should have been so long overlooked by his country.
It fell, therefore, to be the especial duty of the administration
of Mr Fox and Lord Grenville, to correct the oversight of their
predecessors. They created for Mr Stewart the office of Ga-
zette Writer for Scotland, a situation which, as it could be
performed by deputy, required no personal labour, and which
added largely to his income. The creation, or rather the
revival of this office excited a considerable difference of senti-
ment. It was agreed on all hands, that the distinguished in-
dividual on whom it was conferred, merited the highest re-
compense; but it was felt by the independent men of all par-
ties, that a liberal pension from the crown would have express-
ed in a more elegant manner the national gratitude ; and would
have placed Mr Stewart's name more conspicuously in the list
of those public servants, who are repaid in the evening of life
for the devotion of their early days to the honour and interests
of their country.

In the year 1808, Mr Stewart sustained a severe domestic
calamity in the loss of his second and youngest son, who was
cut off by consumption in the 18th year of his age, while pur-
suing his academical studies. To divert his thoughts from
this deep affliction, Mr Stewart devoted himself to the compo-
sition of his Philosophical Essays, a work which appeared in
1810, went through three editions, and added greatly to his
reputation. As the first part of this work is a commentary on

biographical Sketch of the late Dug aid Stezmrt, Esq. 199

some elementary and fundamental questions which divided the
opinions of philosophers in the eighteenth century, Mr Stew-
art regarded it as so far a continuation of his great plan, that
he recommends his younger readers to peruse it after they
have completed the first volume of his Philosophy of the Hu-
man Mind. About a year after the death of his son, Mr
Stewart resigned the Moral Philosophy Chair, and was re-ap-
pointed joint professor along with Dr Thomas Brown. By
this arrangement, which his appointment from Government aU
lowed him to effect, he was enabled to retire from the duties of
active life, and to pursue in retirement those philosophical in-
quiries, of which he had yet published but a small part. He
therefore quitted Edinburgh, and removed with his family to
Kinneil House, near Borrostownness, a seat of the Duke of
Hamilton, and about twenty miles from Edinburgh.

Although it was on Mr Stewart's recommendation that Dr
Brown was raised to the Chair of Moral Philosophy, yet the
appointment did not prove to him a source of unmixed satis-
faction. The fine poetical imagination of Dr Brown, the
quickness of his apprehension, and the acuteness and ingenuity
of his argument, were qualities but little suited to that patient
and continuous research which the phenomena of the mind so
particularly demand. He accordingly composed his lectures
with the same rapidity that he would have done a poem, and
chiefly from the resources of his own highly gifted but excited
mind. Difficulties which had appalled the stoutest intellects,
yielded to his bold analysis, and, despising the patient formali-
ties of a siege, he entered the temple of pneumatology by
storm. When Mr Stewart was apprised that his own favou-
rite and best founded opinions were controverted from the very
chair which he had scarcely quitted ; that the doctrines of his
revered friend and master (Dr Reid) were assailed with severe
and not very respectful animadversions ; and that views even
of a doubtful tendency were freely expounded by his inge-
nious colleague, his feelings were strongly roused ; and though
they were long suppressed by the peculiar circumstances of
his situation, yet he has given them full expression in a very
interesting note in the third volume of his Elements, which is
alike remarkable for the severity and delicacy of its reproof.
Upon the death of Dr Brown, on the 2d of April 1280, Mr

200 Biographical Sketch of the late Dugald Stewart^ Esq.

Stewart resigned the Ghair of Moral Philosophy, and was suc-
ceeded by Professor Wilson, a man of varied and powerful in-
tellect, admired as a poet, and distinguished as an orator.

In October 1810, our eminent countryman, Mr James War-
drop, communicated to Mr Stewart an account of a very re-
markable youth, James Mitchell, who was born both blind
and deaf, and who consequently derived all his knowledge of
external objects from the senses of touch, taste, and smell.
Mr Stewart was delighted with the prospect which this case
afforded of establishing the distinction between the original
and the acquired perceptions of sight. This expectation was not
realized ; but Mr Stewart collected all the facts regarding this
remarkable youth, and embodied them in a highly interesting
memoir, which was read before the Royal Society of Edinburgh
in the beginning of 1812. It is entitled " Some account of a Boy
born Blind and Decif, collected from authentic sources of infor-
mation, with a Jew remarks and comments ; and was published
in the seventh volume of the Transactions of the Royal Society
of Edinburgh. In consequence of the interest which was ex-
cited by this communication, Mr Stewart was anxious that Mit-
chell should be brought to Edinburgh, and educated under the
superintendence of persons capable of studying the develope-
ment of his mental powers. He accordingly submitted this
idea to the council of the Royal Society, who entered eagerly
into the plan, and resolved to apply to Government for a
small pension to enable Miss Mitchell and her brother to re-
side near Edinburgh. Lord Webb Seymour, one of the Vice-
Presidents of the Society, transmitted the wishes of the coun-
cil to the Earl of Liverpool, then First Lord of the Treasury.
The Prime Minister of Great Britain not only refused to sci-
ence and humanity the small pittance which was craved, but
ventured to strengthen the ground of his refusal, by expres-
sing a doubt whether the object which the Society had in view
was likely to add to the comfort of the unfortunate object of
their patronage. The writer of these lines was one of the five
members of council to whom this answer was read, and he
will never forget the impression which it made upon the meet-
ing,— the suppressed feeling of mortification and shame which
was visible on every countenance. The guardian of the Bri-
tish treasury was entitled to refuse the application which had

Biographical Sketch of the late Dugald Stewart^ Esq. 201

been made to him, but he had no right to question the huma-
nity by which that application was dictated. The character
of Mr Dugald Stewart should have been a sufficient guarantee
that the personal comfort and happiness of Mitchell would be
the first objects of his solicitude.

In the year 181 B, Mr Stewart published the second volume
of his Elements of the Philosophy of the Human Mind. This
volume relates entwely io Reason^or the Under standing .^properly
so called., and, as the author himself observes, the subjects of
which it treats are of necessity peculiarly dry and abstruse ;
but he regarded them as so important, that he laboured the
whole of the materials which compose it with the greatest care
and diligence. In the fourth chapter he treats more particu-
larly of the method of inquiry poin<^ed out in the Novum Or-
gaiium of Bacon, and he has directed the attention of his
readers chiefly to such questions as are connected with the
theory of our intellectual faculties, and the primary sources of
experimental knowledge in the laws of the human frame.
, In the month of January 1822, Mr Stewart experienced a
stroke of palsy, which considerably impaired his powers of
speech, and unfitted him in a great degree for the enjoyment
of general society. Unable to take regular exercise, or to use
his right hand, he was reduced to a state of great depen-
dence on those round him. The faculties of his mind, how-
ever, were in no respect impaired by this severe attack, and
with the assistance of his only daughter, who acted as his
amanuensis, and who understood his imperfect articulation, he
was enabled to prepare his works for publication with an ar-
dour of mind and a freshness of intellect which formed a strik-
ing contrast with his bodily weakness

Although the progress of his great work was interrupted
by his Dissertation on the progress of Metaphysical and Ethi-
cal Philosophy, which he composed for the Supplement to the
Encyclopaedia Britannica, yet he was able to complete the
third volume of his Philosophy of the Human Mind in 1827.
This volume contains a continuation of the second part, viz.
two chapters, one on Language, and the other on the Principles
or Law of Sympathetic Imitation; and also the third part, which
consists of two chapters, one on the Varieties of Intellectual
Character f and the other a Comparison between the Faculties

302 Biographical Sketch of the late Dugald Stewart, Esq.

of Man and those of the Lower Animals. To this last chap-
ter he has added as an appendix, his account of James Mit-
chell, with a supplement containing a recent account of the
manners and habits of this interesting individual.

In 1827 and 1828, Mr^Stewart was occupied with the fourth
volume of his Philosophy of the Human Mind, containing his
Inquiries into the Active and Moral Powers of Man, and he
was fortunately able to complete it a few weeks before his death,
and thus to bring to a close that great work, on which he had
spent the flower of his youth, and the maturity of his more
advanced years.

Mr Stewart's health had been for some time declining, but
when he was on a visit to Edinburgh in the month of April
1828, he experienced a fresh paralytic attack which carried
him off on the 11th of June, in the 75th year of his age.
His remains, which were accompanied to the grave by the Ma-
gistrates of the City, and the Professors in the University, were
interred in the family burying-ground in the Canongate
Church-Yard, already honoured as the burial place of Adam
Smith. Mr Stewart's personal friends and admirers have contri-
buted a large sum, with which a monument will be speedily
erected to hi^ memory on some conspicuous spot in our north-
ern metropolis.

Mr Stewart left behind him a widow and two children, a
son and daughter, whom he loved with the tenderest affection.
To Mrs Stewart and his only daughter he owed that sunshine
of happiness, which, but with one cloud. Providence shed over
his domestic life. They had been the ornaments of his social
circle when his public station required him to mix largely with
the world ; and when they were called to higher duties by the
infirmities of his age, they discharged the obligations of conjugal
and filial love with that self-devotion and sustained tenderness
which have their residence only in the female heart. His only
son, Lieutenant-Colonel Matthew Stewart, already known by
an able pamphlet on Indian affairs, and who, we believe, is
now occupied in a larger work on the same subject, was for-
tunately in Scotland at the time of Mr Stewart's death, and was
able to pay the last duties of affection to his venerable parent.
Mr Stewart was about the middle size, and was particularly
distinguished by an expression of benevolence and intelligence.

Biographical Sketch, (rf the late Dugald Stexvart, Esq. 203

which Sir Henry Raeburn has well preserved in his portrait of
him painted for the late Lord Woodhouselee before he had
reached his 55th year. * Mr Stewart had the remarkable pe-
culiarity of vision which made him insensible to the less re-
frangible colours of the spectrum.-j: This affection of the eye
was long unknown both to himself and his friends, and was
discovered from the accidental circumstance of one of his fa-
mily directing his attention to the beauty of the fruit of the
Siberian crab, when he found himself unable to distinguish
the scarlet fruit from the green leaves of the tree.

Mr Stewards name honoured the lists of various learned
academies. He was one of the members of the Philosophical
Society of Edinburgh at its incorporation with the Royal So-
ciety in 1783. He was a fellow of the Royal Society of Lon-
don, an honorary member of the Imperial Academy of Sci-
ences at St Petersburgh, a member of the Royal Academies of
Berlin and of Naples, of the American Philosophical Societies
of Philadelphia and Boston, and honorary member of the
Philosophical Society of Cambridge.

Besides the works which we have mentioned in the course
of this notice, Mr Stewart published his Outlines of Moral
Philosophy^ which appeared in 1793, and which he used as a
text-book. This work has been recently translated into French ;
and it has been used as a text-book in several Colleges in
America. He was also the author of two eloquent pamphlets
on a local controversy now sunk into oblivion. He had laid
down the resolution of never publishing any thing anonymously,
and we believe he never deviated from so excellent a rule.

Before closing this brief sketch, we cannot withhold from
our readers the following admirable observations on the philo-
sophy of Mr Stewart, pronounced at the anniversary meeting
of the Royal Society of London on the 1st of October 1828,
by their distinguished president, Mr Davies Gilbert.

" And here I would call your attention to the loss sustain-

• At a much later period Sir Henry painted another portrait of Mr
Stewart, and Mr Wilkie still more recently executed a striking? likeness of
him in black lead. Mr Joseph has also completed a bust of Mr Stewart
with his usual talent.

t See this Journal, No. xix. p. 153-

204 Biographical Sketch of the late Dugald Stexvart^ Esq.

ed by the world at large in the person of another philosopher,
and fellow of this society, although not a contributor to our
annual publications. Mr Dugald Stewart, imbued with a
taste for mathemati(;al learning by his father's eminence in that
department of knowledge,Jias done more than almost any of
his contemporaries towards preserving from mystery and pa-
radoxes the science which should naturally be of all the most
clear and precise. Following the steps of Bacon and of Locke,
and stored with an extent of reading and of acquired know-
ledge almost beyond example, there can be found few subjects
which he has not illustrated ; and in respect to conclusions
which seem to differ from the deductions of his great prede-
cessors, his arguments are so fairly stated on either side, that
every intelligent reader is placed in a situation to form his own
opinions on those profound and abstruse points. Mr Stewart
has somewhere quoted Ms/^ov sen ro dwafitv am\\)ri%r\v TtrriGac&at
TOM <7roXXag a-Tiodn^stg rojv st/ fMigovg e^e/v. And ' Mathematica
multi sciunt, mathesin pauci. Aliud est enim nosci proposi-
tiones aliquot, et nonnullos ex iis elicere, casu potiusquam
certa aliqua discursendi norma, aliud scientias ipsius naturam
ac indolem prospectam habere, in ejus se adyta penetrare, et
ab universalibus instructum esse praeceptis quibus theoremata
ac problemata innumera excogitandi, eademque demonstrandi
facilitas comparetur. Ut enim pictorum vulgus, prototypon sae-
pe saepius experimendo, quendam pingendi usum, nullam vero
pictori artis, quam optica suggerit, scientiam adquirit, ita mul-
ti, lectis Euclidis et aliorum geometrarum libris, eorum imita-
tione, fingere propositiones aliquos ac demonstrare solent, ip-
sam tamen secretissimam difficiliorum theorematum ac proble-
matum solvendi methodum prorsus ignorent.' By reverting
to the long neglected controversies of the Nominalists and Re-
alists, and by adopting the theories of a most acute and sub-
tle reasoner, who for centuries past has been remembered (such
is the caprice of some) by a reference only to the frailties and
to the misfortunes of his youth, this able metaphysician has
either fully explained, or has pointed out the method of ex-
plaining, every difficulty which seemed to obstruct the use of
imaginary quantities. And by pursuing the same track, if
ancient prejudices, derived from far different speculations.

ft*'

Biographical Sketch of the late Dvgald Stewart, Esq. 205

could once be banished from our minds, it would soon be
found that all circumlocution for avoiding the terms infinite-
ly/ small, infinitely great, and even orders of infinities, might
be dismissed from mathematical language, without produ-
cing uncertainty, mystery, or confusion. I consider, therefore,
Mr Dugald Stewart as a distinguished writer in the higher
departments of mathematics, and eo nomine entitled to our re-
spect and our regard."

The following general view of Mr Stewart's character is given
by one who had every opportunity of knowing it well. *

'' In general company, his manner bordered on reserve;
but it belonged more to the general weight and authority of
his character, than to any reluctance to take his share in the
cheerful intercourse of social life. He was ever ready to ac-
knowledge with a smile the happy sallies of wit, and no man
had a keener sense of the ludicrous, or laughed more heartily
at genuine humour. His deportment and expresion were easy
and unembarrassed, dignified, elegant, and graceful. His po-
liteness was equally free from all affectation, and from all pre-
meditation. It was the spontaneous result of the purity of his
own taste, and of a heart warm with all the benevolent affec-
tions, and was characterized by a truth and readiness of tact
that accommodated his conduct with undeviating propriety to
the circumstances of the present moment, and to the relative
siuation of those to whom he addressed himself. From an
early period of life, he had frequented the best society both
in France and in this country, and he had in a peculiar degree
the air of good company. ,In the society of ladies he appear-
ed to great advantage, and to women of cultivated understand-
ing, his conversation was particularly acceptable and pleasing.
The immense range of his erudition, the attention he had be-
stowed on almost every branch of philosophy, his extensive ac-
quaintance with every department of elegant literature ancient
or modern, and the fund of anecdote and information which
he had collected in the course of his intercouse with the world,
with respect to almost all the eminent men of the day, either

this country or in France, enabled him to find suitable sub-

* Notice of the late Dugald Stewart, Esq. in the Annual Biography and
Obituary for 1828.

206 Professor Del Rio on Chrysolite in Obsidian.

jects for the entertainment of the great variety of visitors of all
descriptions, who at one period frequented his house. In his
domestic circle, his character appeared in its most amiable light,
and by his family he was beloved, and venerated almost to
adoration. So uniform and sustained was the tone of his man-
ners, and so completely was it the result of the habitual influ-
ence of the natural elegance and elevation of his mind on his
external demeanour, that when alone with his wife and his chil-
dren, it hardly differed by a shade from that which he main-
tained in the company of strangers ; for although his fondness,
and familiarity, and playfulness were alike engaging and un-
restrained, he never lost any thing either of his grace or his
dignity : ' Nee vero ille in luce modo, atque in oculis civium
magnus, sed intus domique prgestantior." As a writer of the
English language, — as a public speaker, — as an original, a pro-
found, and a cautious thinker, — as an expounder of truth, — as
an instructor of youth, — as an elegant scholar, — as an accom-
plished gentleman ; — in the exemplary discharge of the social
duties, — in uncompromising consistency and rectitude of prin-
ciple,— in unbending independence, — in the warmth and ten-
derness of his domestic affections, — in sincere and unostenta-
tious piety, — in the purity and innocence of his life, — ^ew have
excelled him : and, take him for all in all, it will be difficult
to find a man, who, to so many of the perfections, has added
so few of the imperfections of human nature."

Art. II, — Notice respecting the existence of Chrysolite in
Obsidian^ as discovered by iProfessor Del Rio,
Sir,
In the eighth volume of the Ediiiburgh Journal of Science^ *
the following article appears under the head of Mineralogy.

Chrysolite in the cavities of obsidian. — Professor Gustavus
Rose of Berlin has found in the cavities of obsidian, in the
Jacal Rock, near Real del Monte in Mexico, little crystals,
greenish and reddish yellow, and transparent, which belong to
the species of prismatic chrysolite. — Poggendorfs Annalen,
vol. X. p. 323.

• No. XV. p. 121.
3

, .4

PLATE II.

/;///, ' /,'U,n.,/vf.Vnei,ee Y«t^

Fuf. 8 .

/•/y . 10

Fiv ■ II ■

Liiars Sculp*.

Don Bustamente 07i a neiv Gravimeter. 207

One of the English pupils of Professor Del Rio presumes
to suggest, that it would be but an act of justice to that pro-
found mineralogist and eminent scholar to state, that, as far
back as the year 1804, he stated in a note at page SS of his
translation of Karsten's Mineralogical Tables, that he had
made the same discovery, as will be seen from the following
extract : —

Los cristalitos de olivino de Zinapeguaro estan de canto so-
bre las eras 6 quadritos de la substancia blanca nueva que he
Uamado equinolita contenida an las cavidades de la obsidiana
de alii; siendo muy peguenos juzgue al principio por el color
que fueran de obsidiana ; pero al soplete no se funden, solo to-
man un viso negro de hierro y con borax se funden en vidrio
verde claro. Son de color verde a ceytuna, transparentes,
rayados a lo largo, y parecen tablas octagonas prolongadas con
todas las aristas laterales truncadas.""

The above is from a note to Olivine, extracted from a
work replete with profound mineralogical knowledge ; but
which, from its being published in Mexico and in Spanish, is
but little known in Europe.

At the same time that I submit this for your consideration,
I beg to inclose the description and drawing of an instrument
for weighing specific gravities, invented by Don Jose Maria
Bustamente ; the ingenuity and simplicity of which will, I
have no doubt, induce you to take notice of it in your excel-
lent Journal. It appears calculated to supersede altogether
the use of Nicolson's balance weight. — I have the honour to
be, Sir, your faithful and obedient servant,

Mexico, SUt October 1828.

AiiT. III. — Description and use of a new Gravimeter, By

Don Jose Maria Bustamente.

It is known, that, to be able to use Nicolson's Balance, a set

of small and correct wrights is necessary, and that it requires

to be sunk in water to a certain depth, that is, to place it in

its index three times during the operation. Eor this it is ne-

• It will give us great pleasure to be favoured with the continuance of
the correspondence of X.

208 Don Bustamente on a nexv Gravimeter.

cessary to be adding and taking away the weights as may be
required, to bring that point exactly level with the surface of
the water, which proceeding is tedious. Besides on journeys,
where the conveniences one has at home are generally wanting,
it is very easy to lose some of such small weights, by which
means an instrument so useful to the travelling mineralogist
is rendered useless. To avoid these inconveniences, faci-
litate the transport of the instrument, and simplify the opera-
tion, I make use of the instrument which is represented in
Fig. 1, ^, and 3 of Plate II., which gives the necessary instruc-
tions for ascertaining the specific weight of minerals with great
exactness without weights.

2. The part a b c oi the instrument, which may be of tin,
brass, &c. is composed of two inverted cones, hollow and
united at d e^ as Fig. 1 shows, the base of which is a concave
plate, afh^ which receives the minerals that are weighed in
water. Before soldering this plate, the instrument must be bal-
lasted, that is, a portion of lead is put into it so as to sink it
in the water till near the base a 6.*

3. In four points of this base, opposed at right angles, are
soldered two arches of wire a b, g h^ which cross, and sustain
the hoop m, which receives the end of a crystal tube m n, made
fast with sealing wax. In the interior of the tube is placed a
scale of lines, of millimetres or of equal arbitrary parts traced
on paper, and the divisions of which are numbered from zero
upwards.*!*

4. Finally, on the other end of the tube is fixed, by means of
a hoop and sealing wax, the plate r s, which is used for putting
the minerals into when they are required to be weighed in air.

5. Figure 2 is a' cylindrical box of tin with its cover, of the

* The ballast may be of lead, in flat pieces, or small shot. In the first
instance, it is well fitted, and stuck to the sides of the inferior cone ; but
in the other two it will be necessary to fix it with a cover of tin soldered
to the cone, so that they do not shake about, and are always kept at the
bottom.

t Instead of a glass tube, one of silver or brass might be used of the
corresponding size and weight. On the outside let there be a scale of
equal parts ; then suppress the hoops ; and the arches, as well as the plate,
will be better fixed to the tube, and the instrument less exposed to get
damaged.

Don Bustamente 07i a new Gravimeter. 209

same length as the instrument, and th^ diameter of which
is aHttle greater. In the interior of the bottom is firmly sol-
dered the conical end x z, in which is fitted a part of the cone
dec, and, as the diameter of the upper plate ought to be very
little less than that of the box, the instrument placed with-
in this cannot be shaken so as to spoil it ; and in this manner
it can be moved about with much convenience and security.
This box is also best for using the instrument, because a
sufficient quantity of water being put into it, and the instru-
ment being submerged, the water only reaches the brim with-
out spilling.

6. When the instrument is left to itself in the water, it sinks
to very near the base a 6, as we have said, and it is necessary,
in order that the zero of the scale should reach the level of the
water, to put some little weights of lead in the upper plate ;
the weight of which ought to be ascertained, so that it may
always sink to that one point; and this new weight we will call
additional weight.

7. If when in this state we put on the plate any weight, the
greater the weight the deeper it sinks ; and there is no doubt
that this new weight is equal to that of a cylinder of water
equal to the portion of tube that has been sunk, because the
space that this occupies in the liquid is equal to that occupied
by the cylinder of water which it dislodged, and the force of
the liquid to sustain it is also equal to that of the weight of
the substance, to be able to keep immersed that portion of the
tube. Thus, then, if the instrument sinks one of the divisions
of the scale, we can say that the weight with which it is char-
ged is equal to that of a cylindrical portion of water whose
base is the section of the tube, and whose height is one divi-
sion. A greater load will immerge it 20 divisions, and will be
equivalent to the weight of 20 portions equal to the preced-
ing. Knowing, then, the number of drachms or grains that
each of these portions weighs, we shall be able to ascertain the
weight of the substance that we put on the plate.

8. Afterwards we will show how the weight of each portion
is known, although there is no necessity for its being known ;
because the divisions of the scale show us the correspondence
of the weights that we put on the plate, in the same manner

VOL. X. NO. II. APRIL 1829- O

210 Don Bu stamen te on a new Graxnmeter.

as there is no necessity for knowing the weight of the mercury
contained in the tube of the barometer for ascertaining and
comparing the various pressures of the air. It is sufficient, then,
for us to fix with precision the point of the scale at which
the water stands, before loading the instrument, and that to
which it sinks in consequence of the loading applied : To this
alone is its use reduced.

9. Suppose that, being loaded with an additional weight, the
level of the water reaches exactly the zero of the scale, if in
this state we put on the upper plate a fragment of calcareous
spar for example, the weight of which produces an immersion,
so that the level of the water should mark the division 54,
this number shows us the weight of the fragment weighed in
air (§ 7.) If we change then the fragment to the lower plate
the immersion only reaches to 84, and this number shows us
the weight of the same fragment weighed in water. Then the
difference of 20 between these two numbers is exactly the
weight of the volume of water dislodged by this substance, or
the weight lost in the second operation. There remains only to
divide 54, the weight of the fragment in air, by 20, which is that
which is lost in water. The quotient, 2.7, shows us the specific
weight of the calcareous spar; and this simple method must be
followed for all other bodies.

10. It is easily perceived that the additional weight may be
greater than we supposed, without its altering the data, be-
cause if, instead of sinking the instrument to zero, it should be
sunk to the division 8 for example, then the same fragment of
calcareous spar would have immerged it not only to 54 but
to 62, and always its weight in air would be the same as before,
that is to say, 62 — 8 = 54. The same happens with the weight
in water. In the second instance the immersion would not be
to 34, but would rise to 42, and the loss would be equal to the
former, that is 62 — 42 = 20 ; and this is one of the advanta-
ges of the instrument, that it is not requisite to bring it to any
fixed point, but only to observe the divisions of the scale which
mark the level of the water, as already said (§ 8.)

11. If we take away from the upper plate not only the sub-
stance that has been weighed, but also the additional weight,
the instrument rises till it leaves the lower plate above the

Don Bustamente on a new Gravimeter, 211

water (§ 2), and from this construction results the convenience
of being able to place the substance on this plate, without
taking the whole instrument out of the water, and without
being exposed in the second immersion to any bubbles of air
rising, which was not the case in the first, but which often hap-
pens with Nicolson''s balance, which alters the results.

12. The level of the water always leaves some doubt in the
determination of the precise point of the scale to which it
reaches, chiefly when it is to mark the parts of a division ; and
in its stead we could use another index much more exact, the
simplicity of which recommends its constant use. It consists
in placing two threads of silk, ah, c d, (Fig. 3.) well stretch-
ed, or of very fine wire, called hair-wire, on the opposite points
of the edge r s, of the box or case, so as to encircle the glass
tube without pressing it, and allowing it to move freely in the
middle, for which purpose are placed the buttons m, n, soldered
strongly to the case, and the small grooves a, c, b, d, made on the
same edge ; then observing through the hollow x z, which is
about two lines high and one inch long, the level of the threads
and also of the scale, the thread that is on the side of the ob-
server marks the divisions and parts of each to which the im-
mersion reaches, and by these means, if the scale is of milli-
metres, (French measure,) may be seen at one view the fifth
part of each, or two-tenths of a millimetre, which is equivalent
in the instrument which I use to a weight of 0.3 grains. It
is true that this mode indicates the point of partition a little
above zero in the scale ; but as we have seen, (§ 10,) this does
not alter the results.

13. Till now we have only spoken of the mode of weighing
substances, the specific gravity of which is greater than that of
water. We have then two other cases to consider that can oc-
cur, and they are those in which the specific gravity of the sub-
stance is equal to or less than that of water.

14. If knowing the weight of a body in air, for example 24,
we weigh it in water, and find that the immersion reaches ex-
actly to zero, in this case we should say that it had lost all
its weight, or that it is equal to the body of water which it dis-
lodges, because the difference between zero and 24 is 24, and
its specific gravity will be || = 1 = to that of the water.

212 Don Bustamente on a new Gravimeter.

15. But if, instead of the second immersion reaching zero,
it should remain six divisions below this point, supposing that
the scale should have negative divisions, that is, that it should
continue below zero, this would show us that the volume of
water dislodged weighs more than the substance, because it
not only loses from 24 of its weight, but besides, makes the
instrument lose six, with which it forms a whole, and the dif-
ference between + 24, which it weighs in air, and — 6 in water,
observing the rules of the signs, is + 30, dividing 24 by 30,
we get 0.8, that is, the specific gravity of the substance is less
than that of water.

16. We have not put on the scales negative divisions, be-
cause it would increase much the neck of the instrument, and,
besides other inconveniences, would render it more bulky.
There is no necessity for these divisions, if we consider, that,
by increasing the additional weight, we can sink the greater
part of the scale, in order that the substance that we might
weigh in water should afterwards make it rise, and by this
simple proceeding we can say, that, without altering the size
of our scale, we have doubled it. An example will illustrate
this.

1 7. Suppose a small piece of oak weighs in air 43.3, taking
it from the upper plate, and increasing the additional weight?
we shall make the scale sink to 60 for example. Marking this
point, which we shall consider as though it were the zero of
the scale, and weighing afterwards the wood in water, the im-
mersion only reaches to 53, that is, it has seven divisions, which
certainly correspond below zero. The difference, then, be-
tween -f- 43.3, weight of the oak in air, and — 7.0, its weight in
water, is -f- 50.3. Dividing 43.3 by 50.3, the quotient, 0.860,
results, which is the specific gravity of oak ; and this operation
will be observed in other instances.

18. If, when the instrument is at zero, we place known
weights, such as drachms and grains, we shall know the cor-
responding weight of each division of those that are immersed,
dividing the number of drachms or grains by the number of
divisions; so then, if with 3 drachms or 108 grains it sinks 54
divisions, each one will correspond to 2 grains, and in this
manner we shall know how far the greatest weight that can
be weighed in this instrument ascends.

Mr Kenwood's Account of Steam-Engines in Cornwall. 213

Art. IV. — Notice of the performance of Steam-Engines in
Cornwall for October, November , and December 1 828.
By W. J. Kenwood, Esq. F. G. S., Member of the Royal
Geological Society of Cornwall. Communicated by the
Author. ' '^

Reciprocating Engines drawing Water.

Mines.

5;S

! Length of
stroke in cy-
linder in feet.

Length of
stroke in the
pump in feet.

Load in lbs. per
sq. in. of area
of piston.

No. of strokes
per minute.

Millions of lbs.
weight lifted I
foot high by the
consumption of
J 1 bush.of coaL

Huel Towan,

10,

10,3 6,4

75,2

10,

5,1 3,7

58,5

Cardrew Downs,

8,75

10,1 5,5

63,8

Kuel Kope,

10,38 5,2

70,

Huel Vor,

63*

7,25

5,75

17,5 5,1

22,5

7,5

19,58 5,1

38,

8,09 3,9

27,5

10,

7,5

14,96 5,4

57,5

6,75

5,5

13,6 5,7

49,1

Poladras Downs,

10,

7,5

8,97 4,9

45,6

Kuel Reeth, -

7,5

15,29 3,9

24,5

Balnoon,

6, 3,9

20,6

Kuel Pen with, -

8,75

4, 6,3

25,3

United Kills, -

8,25

6,5

6,79 4,1

36,6

Great St George,

60.

10,333 6,5

9,4 4,

30,3

10,

7,5

10,4 3,8

34,1

Crinnis Mines, -

8,25

11,68 4.4

27,9

6,75

6,75-

10, 5,1

32,3

Perran Mines, -

6,75

8,2 7,7

19,4

Stray Park,

7,75

5,25

7,66 4,

26,7

Carzise,

8,5

7,34 4,

27,6

Kuel Penrose, -

8,5

6,5

10,35 6,3

33,

Kuel Caroline, -

28, 10,2

36,2

Kuel Trevoole, -

. 30

22,19 ^,5

37,9

St Ives Consols,

16,1 6,2

30,6

Lelant Consols,

7,5

4,5

17, 2,9

14,6

21 4 Mr Kenwood's Account of Steam-Engines in Cornwall.

*s.s

.^1

-M.

bs. per
if area

trokes
.te.

of lbs.

fted I
by the
tion of
fcoal.

Mines.

°.s.s

7,5

® C (3 •

111:

5,75

— • o £3

21,5

Ci No. of s
per minu

1 Millions!

weight li
foot high
consumpi
1 bush, ol

Huel Damsel, -

42 1

34,1

8,2

2,4

31,

Ting Tang, -

7,75

6,75

15,

6,4

41,8

Huel Beauchamp,

7,75

11,6

4,1

33,

Huel Montague,

8,1

5,7

31,9

Great Work, -

8,9

6,2

37,4

East Huel Unity,

8,75

6,75

7,97

4,1

27,9

Tresavean,

5fi

4,2

20,8

Huel Unity, -

5,5

14,4

5,6

27,6

Poldice,

9,5

6,25

11,9

5,9

31,2

10,

i0,9

5,5

54,

North Downs, -

9,833

7,75

7,9

Qfi

47,4

Huel Busy,

10,

7,5

11,4

6,2

46,8

Huel Tolgus, -

10,

7,5

3,4

44,8

Dolcoath,

7,5

11,8

43,4

East Crinnis,

5,5

8,57

4,5

21,7

10,

8,4

4,1

31,9

Binner Downs,

10,

7,5

10,93 7,6

61,9

7,5

7,87

8,9

36,6

7,5

11,8

6.8

46,

Pembroke,

6,5

6,1

24,5

9,75

7,25

11,27 3,4

44,1

United Mines, -

7,5

^12,9

7,1

33J

8, '

^7,9

38,7

Consolidated Mines, 90

10,

7,5

8,82

5,1

58,1

10,

7,5

9,1

5,2

55,1

7,75

6,5

17,7

6,3

39,9

10,

7,5

10,6

3,7

29,2

10,

7,5

8,8

4,7

60,4

10,

7,5

7,83

5,5

63,2

Average dufy 88.6 millions of lbs. lifted one foot high by
the consumption of each bushel of coal.

Dr Brewster on the motions of the Molecules of Bodies. 215

Watt's rotatory double engines working machines for bruis-
ing tin ores at

Length of
crank in feet.

Huel Vor, 24 6. 8. 12. 16.9 17.
27 5. 2.5 12.5 17.3 19.7
16.5 5. 2.5 8.5 9.B.Q 13.4
Average duty of rotatory double engines, 16.7 millions.

* Watt's double engine.

-f The steam is first admitted into a high pressure cylinder,
whence it passes into a Watt's single engine, both pistons be-
ing connected with the same lever. All the others are Watt's
single engines.

Art. V. — Observations relative to the Motions of the Mole-'
cules of Bodies. By David Brewster, LL. D. F. R. SS.
London and Edinburgh.

jNoTwiTHSTANDiNa the great interest which has been every-
where excited by the observations of Mr Brown respecting the
motions of the Molecules of Bodies, I should not have thought
of calling the attention of the Society to the opinions which I
entertained, or to the experiment which 1 had accidentally
'made in reference to this subject.

As I am, however, the only surviving member of those who
took an active part in the discussion and examination of this
matter when it was presented to the consideration of this So-
ciety nearly fifteen years ago, I feel it incumbent upon me to
call your attention to the facts and views which then came un-
der our .notice.

On the 2d May 1814, Dr Drummond of Belfast communi-
cated to tliis Society a paper " On certain appearances ohserv-

' ed in the dissection of the Eyes of Fishes.'''' Having washed
off the silvery part of the choroid coat of the haddock into

I about half a teaspoonful of water, the water became of a milky
colour, owing to innumerable slender, flat, silvery spicula,
which composed the substance of the choroid. " They seem-

216 Dr Brewster on the motions of the Molecules of Bodies.

ed,"** says Dr Drummond, *' to be in constant motion, appa-
rently rolling upon their axis, but having no degree of pro-
gressive movement. The light reflected from their surface was
very brilliant, like that from polished silver, and often disap-
peared, and again returned, with alternations so rapid, as to
produce a twinkling very like that of a fixed star.

** Sometimes on examining an individual specimen it would
disappear altogether, but in a few minutes return, renew its
twinkling and apparent revolution on its axis, and again dis-
appear to return as before.

" Frequently, also, some were observed to be in the fluid, or
on its surface, for a long time motionless, but very brilliant ;
then they would give a few slight twinkles, seem to turn round,
and almost disappear ; then resume their original situation for a
moment, appear more brilliant than at first, partly disappear
again, and again return, and so on for a number of times, till
at length they would disappear entirely ; but after a time (per-
haps five or ten minutes) show themselves in the same spot as
before. These observations could be made only on the larger
spicula; the minute ones being in incessant motion.

" I'he motion continues in a great many of the spicula even
after the fluid containing them has become putrid ; but it is
then more slow. The addition of ardent spirits deadens but
does not destroy the motion. After exposure to a heat of
boihng water, the number of spicula seems much diminished,
and those which remain move less rapidly than before. The
addition of vinegar, in a quantity equal to the fluid contain-
ing the spicula, suddenly causes a great diminution of the
number of moving ones, probably from coagulating the albu-
minous matter which had been washed from the eye along
with the spicula, and entangling them in it. Many, however,
continue their motion as before.

" The spicula of the eye of the herring are jointed, being ge-
nerally thus divided into three distinct portions, of which that
which forms the centre is much larger than the two others.
In common daylight, the entire spiculum is silvery ; but if it
be observed in the sunshine, it will be found to reflect differ-
ent rays from the jointed portions ; the end joints being gene-

Dr Brewster wi the motions of the Molecules of Bodies. 217

rally of a light straw colour^ while the central one is steel blue,
like the main spring of a watch, or of a red or light rose co-
lour, sometimes silvery, green, or purple ; but never of the
same colour as the extremities of the spiculum. The colours
of the different joints do not shade into each other, but termi-
nate abruptly by a well defined line.""

Dr Drummond next proceeds to account for the motion of
these spiculae, and after discussing many objections against
the supposition that they are animalcules, and especially the
formidable objection drawn from their surviving the heat of
boiling water, he concludes with the following opinion of their
probable origin.

" Perhaps many other objections may be opposed to the
supposition of animalcular life in these bodies, and yet the
strong expression of animation, if I may so term it, and air of
seeming design, with which the varying motions (sometimes
slow and sometimes rapid) are performed, and the difficulty
of otherwise accounting for their motion, whether real or ap-
parent, lead, upon the whole, T think, to this supposition, not
as one which we can admit with confidence, but as the least
improbable conjecture, which, in the present limited state of our
knowledge, we can venture to form.""

Although I never could assent to this conclusion, yet I can
bear testimony to the perfect accuracy of the statement pub-
lished in Dr Drummond's paper. The late Dr Thomas
Brown and I repeated most of the experiments, and witnes-
sed all the movements and revolutions of the spicula above-men-
tioned. I was disposed at that time to regard them as the re-
sult partly of a polarity in the spicula themselves, and partly
of certain physical changes, to which bodies are peculiarly li-
able when suspended in a fluid medium.

In order to determine whether or not these minute scales
acted upon one another, I prepared a considerable quantity of
the milky fluid, and spread it out upon a large square of glass,
in the expectation that the spicula would (like the minute par-
ticles of crystalline matter) form an organized film that would
exhibit the proof of molecular polarity by its action upon po-
larized light. When the water had evaporated, I obtained a
film or crust exactly similar to that which converts glass balls

218 Dr Brewster on the motions of the Molecules of Bodies.

and spheres of gypsum into artificial pearls ; but it exhibited
no organized structure, and consequently indicated no polari-
ty in the elementary spicula.

In making these experiments, I was often surprised by a
singular variation in the whiteness of the large plate of fluid
when spread over the square of glass. It sometimes appear-
ed to be quite dark, and at other times to recover its white-
ness without any apparent cause. This, however, I found to
arise from currents of air arising from my own motion across
the room, and I could make the fluid appear white or dark at
pleasure, by merely blowing over its surface. When the fluid
surface was in a state of rest, the spicula settled in certain po-
sitions in relation to a vertical line ; but whenever a breath of
air affected the fluid they were thrown into new positions, and
reflected the incident light in a different manner.

Owing to the great extent of surface which was thus expos-
ed to accidental impressions, the movements of the spicula
were much more lively than when they were examined in small
portions of fluid ; but the slightest examination was sufficient
to satisfy me that their movements were entirely the result of
the position of unstable equilibrium which they occupied in the
fluid medium.

Since these experiments were made, I have observed analo-
gous motions, though arising from a different cause, in the
juice of the Semecarpus anacardium^ and I am persuaded
that they will be found in all organized fluids. When this
fluid, or a portion of the black Indian varnish, (which is a
mixture of the sap of the Semecarpus anacardium with that of
the Jowar^) is placed between two plates of glass, and illumi-
nated in the microscope by the sun's rays, the particles seem
to be all in motion, and there appears a most singular and ra-
pid play of colours, arising from the inflexion of the light
which passes between the organized molecules. The very
same phenomenon has been observed by M. Dutrochet in
blood taken either from the veins or arteries of an animal, and
the motion of its particles ceases only when the blood coagu-
lates.

In examining the motions of the granules of pollen suspend-
ed in water, (which I have done since the publication of Mr

Dr Brewster on the Motion of the Molecules of Bodies. 219

Brown's observations), I recognized the same changes which I
have already mentioned ; but I have never perceived a single
motion in the least degree characteristic of animal life. The
difference between these two kinds of motions, and the causes
to which the former may be ascribed, are so admirably ex-
plained in a memoir which I have lately received from that
eminent French physiologist, M. Raspail, that I need make
no apology for laying before the Society a translation of the
most prominent part of it. It was read at the Institute of
France before Mr Brown's observations had reached Paris,
and was drawn up in reference to the Memoir of M. Adolphe
Brongniart, which had excited much notice.*

It is impossible, we think, for any person familiar with the
microscope, to read these observations of M. Raspail without
being satisfied of their accuracy, and without believing that
they are applicable to almost all the phenomena observed by
Mr Brown and M. Brongniart. But even if they did not af-
ford a sufficient explanation of the motions in question ; — nay,
if these motions resisted every method of explanation, it is the
last supposition in philosophy that they are owing to animal
life ; and in future times, when the science of molecular orga-
nization shall be farther advanced, it will be viewed in the
same light as the opinion of Kepler, that the planets them-
selves were living animals, swimming in the ethereal ocean
of the heavens. What, indeed, are all the motions of the
planets, — what are their progressions, their stations, their
retrogradations — their revolutions — their nutations, but so
many movements in the larger molecules of the universe.
Why, then, need we wonder that the microscopic molecules of
this lower world should exhibit their attractions, their rota-
tions, their combinations, their dilatations, and their contrac-
tions ? We are disposed, indeed, to go much farther, and to
ask, Why should not the molecules of the hardest solids have
their orbits, their centres of attraction, and the same varied
movements which are observed in planetary and nebulous
matter ? The existence of such movements has already been
recognized in mineral and other bodies. A piece of sugar melted

• The whole of this Memoir was published in our last Number, p. 96.

2^ Commander Pearse on the Formation of Anchors.

by heat, and without any regular arrangement of its particles,
will in process of time gradually change its character, and con-
vert itself into regular crystals, possessing a mathematical re-
gularity of structure, and displaying all the wonderful pheno-
mena of double refraction. A mineral body will, in the course
of time, part with some of its ingredients, or take in others,
till it has become a new mineral, and has entirely lost its per-
sonal identity ; — and (what has recently been discovered by a
foreign member of this Society,) a regular crystal may, by the
mere introduction of heat, have the whole arrangement of its
molecules converted into an opposite arrangement, developing
new physical properties which it did not before possess. In
these changes the molecules must have turned round their axes,
and taken up new positions within the solid, while its external
form has suffered no apparent change, and while its general
properties of solidity and transparency have remained unalter-
ed. Before another century passes away, the laws of such
movements will probably be determined ; and when the mole-
cular world shall thus have surrendered her strongholds, we
may look for a new extension of the power of man over the
products of inorganic nature.

Ai.iu:EiiJ.Y, December ]3, 1828.

Art. VI. — Remar'ks on the formation of Anchors. By Com-
mander John Pearse, R. N. Communicated by the
Author.

It does not appear that the formation of anchors has been very
generally viewed by seamen on such principles as would enable
them to form a just conclusion of that best adapted for the
safety of a ship. Very old seamen argue in favour of a long
shanked anchor, without being able to offer anything satisfac-
tory in support of it ; and such an opinion is no doubt gene-
rally formed from custom or prejudice. I shall therefore en-
deavour to illustrate, on mathematical principles, what appears
to be the advantages of a short shank.

Figures 4th and 5th of Plate II. are intended to represent

Commander Pearse on the Formation of AncJiors. 221

anchors of the same weight, differing in the length of their
shanks, but having arms of equal length, and forming the
same angles with the shanks. The lower arms are supposed
to be buried in the ground, as denoted by the dotted lines DE
and CF. The hues AA represent the cables.

It will appear evident that the strain of the ship must
operate at the points B,B, and, therefore, by the principles of
the lever, CB, in Figure 4th, being longer, and consequently
producing a greater power than DB in Figure 5th, the for-
mer must be more liable to break its hold than the latter, and
a ship, consequently, must ride the safest with a short-shanked
anchor.

It is a great advantage to have a good holding anchor, when
getting a ship under weigh in a confined harbour, when
anchored among many ships, or when blowing strong, as it
admits of the cable being hove very short, without danger,
before the sails are hoisted. It lessens also the labour and
time in heaving in cable afterwards, and often prevents the
anchor from breaking its hold before the cable is up and down,
or perpendicular. And at those times the advantage must ap-
pear in favour of a short shank.

If two anchors are of the same weight, and the same length
in their arms, but differing in the lengths of their shanks, the
several parts of the short one must be of greater substance,
and consequently much stronger.

There appears, however, to be another advantage in favour
of a short shank. Figures 6th and 7th represent two anchors
of the same dimensions as Figures 4tli and 5th. They are both
supposed to have just taken the ground. It will be seen that
the lower arm of Figure 7th is nearer a perpendicular than the
arm of Figure 6th ; consequently, it will at first strike deeper,
and take a firmer hold in the ground, and be more likely to
retain it in the event of being checked by the cable. This will
be an advantage when anchoring and confined for room, or
when pointing a cable and having to let go the short or spare
anchor.

As far as I can speak from my own practical experience, I give
the preference to the short shank. I have commanded different
vessels nearly eight years, and the whole time accustomed to

222 Mr Marshall's Meteorological Summary for 1828.

wild open roadsteads, and I believe no ships ever started their
anchors so seldom ; and I have always selected the shortest
shank anchors I could get. I did it also before I commanded
vessels, when the selection was left to myself. I did this at
first, in consequence of the appearance of their formation pleas-
ing me better, and I afterwards viewed it on the principles I
have now explained, and I have found the theory and practice
completely to agree.

Plymouth, December 17, 1828.

Art. VII. — Summary of the state of the Barometer^ Ther^
mometer, ^c. in Kendal^ for the year 1828. By Mr Samuel
Marshall. Communicated by the Author.

Quantity

Number

1828.

Barometer.

Thermometer.

of Rain in
Inches.

of Rainy Prevalent

Max.

Min. Mean

Max.

Min.

Mean.

Days.

Winds.

J^n.

30.17

28.9829.67

50°

23°

39.17°

6.192

s. w.

Feb.

30.18

28.89

29.57

38.93

4.625

s. w.

March,

30.12

28.75

29.69

42.09

2.440

April,

30.14

29.08

29.54

45.45

4.012

May,

30.17

29.29

29.69

53.12

1.961

June,

30.09

29.08

29.78

81.5

59.07

3.078

July,

29.83

29.12

29.50

58.62

3.502

Aug.

30.14

28.89

29.65

58.25

5.581

Sept.

30.40

29.15

29.78

33.5

55.05

4.497

Oct.

30.40

28.95

29.86

60 5

28.5

47.86

4.916

Nov.

30.18

29.09

29.65

54.5

44.64

4.786

Dec.

30.27

2899

29.64

52 5

44.20

9.226

Means,

30.17

29.0229.66

63.16

31.41

48.87^54.816

189

The year 1828 has been distinguished by its being a war-
mer year than any of the preceding five years, the latter part
being seldom equalled in uniform mildness ; the thermometer
never having indicated frost from summer to the end of the
year, but three times in October, twice in November, and
twice in December. The appearance of the Aurora Borealis
has not been more frequent than has occurred within the last

Mr Marshall's Meteorological Summary for ^ 828. 223

few years. Thunder and lightning have oftener occurred
during the latter part of the year than is usual in winter.
Though it is only by simultaneous observations in different
parts of the globe, on a large and extensive scale, and by com-
paring these with each other, that great and important results
can be obtained, and fresh discoveries made in the imperfectly
developed science of meteorology, yet more humble efforts^
confined to particular districts, are requisite to confirm and
establish them. Such labours are, therefore, needful and de-
cidedly auxiliary to forming the great outline, which every one
conversant in this science acknowledges to be a desideratum.
To decide on the causes which produce certain atmospheric
phenomena that are regularly occurring in any particular dis-
trict, has yet been imperfectly obtained ; and yet that they
depend on general principles, capable of producing those phe-
nomena, can hardly be denied. It is to be regretted that few
are willing to undertake the labour requisite for obtaining this
local information, and without which, the deductions derived
from more extended observations would be incomplete.

I shall attempt in this paper, to make a comparison of the
weight of the atmosphere at different times of the year, for the
last six years, in which I have kept a regular register of the
weather, — point out the months in which the greatest and least
quantities of rain have been taken, &c. by which certain infe-
rences may be drawn of the meteorological facts of the dis-
strict. It is requisite, however, to state, that the situation in
which these observations have been taken is about forty-two
yards above the level of the sea ; that the time of registering
the daily observations is nine o'clock, a. m. ; and that the quan-
tity of rain which has fallen within the preceding twenty-four
hours (if any) is registered daily at that time. The mean
height of the barometer for 1828, is the exact average of the
last six years, including the year 1828^ The greatest height
which the barometer attained was on the 16th of September
and the 29th of October, 30.40 inches, in both which instan-
ces remarkably fine clear weather had preceded and followed,
though in September it was rather succeeded by fine weather,
than preceded by it, as before that date we had heavy rain, till
within two days of its having attained its greatest altitude.

224 Mr Marshal rs Meteorological Summary for 1828.

During tkejmonth of October it exceeded 30 inches for fifteen
days, from the 11th to the end of the month, with the excep-
tion of six days. To this circumstance may be attributed the
reason of the means being greatest for that month than any
through the year. The greatest depression was on the 21st
of March, about which period we had frequent rain, snow, and
sleet showers.

The mean height of the thermometer is greater than in any
other year for the last six years. It was at its greatest altitude
on the 28th June, 81.5°. Thunder and lightning were very
frequent during a great part of this month, and the weather
was mostly dull and cloudy. The greatest degree of cold was
experienced on the 11th of January, and on the 12th and 16th
of February. In the early part of January the weather was
mostly severe, and about the middle of February we had
heavier falls of snow than in any other part of the year. In

1823, 1825, and 1827, the month of July was the hottest;
(deducing this conclusion from the mean for the month,) in
1826 and 1828, that of June, and in 1824, August. In 1823,

1824, 1825, and 1826, January was by the same rule the
coldest month ; and in 1827 and 1828 February. The ave-
rage temperatures of the hottest months for the last six years
is 59.06°, and that of the coldest months is 34.57.° The hottest
month in that period was June 1826, and the coldest January
1826.

The quantity of rain for 1 828 is less than that of any other
year for the last seven years, excepting only 1826, which was
but 43.060 inches. The mean quantity of rain for the last
seven years is 57-727 inches. The greatest quantity taken
in any year in that period was in 1824, 62.762 inches, and the
least in 1826. The greatest quantity of rain in any month
was in November 1824, 13.433 inches, and the least in May
1826, 0.369. The greatest quantity in a day, in 1828, taken
for the preceding twenty-four hours, was on the 8th of October,
1.420 inch.

The number of rainy days has not been equalled in any of
the last six years, except in 1823, which was 198. The num-
ber of days on which rain has fallen in the months of April,
May, June, July, August, and September, is 84 ; and in the

Great Congress of Philosophers at Berlin. 2^5

months of January, February, March, October, November,
and December, 125. The west wind has been this year more
prevalent than any other, though in general the wind from
the S. W. is decidedly the prevalent wind of Kendal. The
wind from the west has prevailed 1 24 days during the course
of the year ; from the S. W. 83 days ; from the N. 40 ; N. W.
32; S. 30; E. 23; N. E. 22; and from the S. E. 12 days.

Perhaps it will be thought that these remarks are too mi-
nute for the purpose for which they are designed ; but I
conceive the imputation will be allowed to be groundless,
when it is recollected that they are intended to describe some
of the peculiarities for which this district is remarkable.

Art. VIII. — Account of the great Congress of Philosophers at
Berlin 07i the ISth September 1828. Communicated by a
Correspondent.

Ihe existence of a large society of cultivators of the natural
sciences meeting annually at some great capital, or some cen-
tral town of Europe, is a circumstance almost unknown to us,
and deserving of our attention, from the important advantages
which may arise from it.

About eight years ago, Dr Okens of Munich suggested a
plan for an annual meeting of all Germans who cultivated the
Sciences of medicine and botany. The first meeting, of about
forty members, took place at Leipsic in 1822, and it was suc-
cessively held at Halle, Wurtzburg, Frankfort on the Maine,
Dresden, Munich, and Berlin. All those who had printed a
certain number of sheets of their inquiries on these subjects
were considered members of this academy.

The great advantages which resulted to these sciences from
the communication of observations from all quarters of Ger-
many soon induced an extension of the plan, and other de*
partments of natural knowledge were admitted, until, at the
last meeting, the cultivators even of pure mathematics were
found amongst the ranks of this Academy.

Several circumstances, independent of the form and consti-
tution of the academy, contribute'd to give unwonted splendour

VOL. X. NO. II. APRIL 1829. . P

926 Great Congress of Philosophers at Berlin.

to the last meeting, which took place at Berlin in the middle
of September of the last year.

The capital selected for its temporary residence is scarcely
surpassed by any in Europe in the number and celebrity of its
Savans.

The taste for knowledge possessed by the reigning family has
madfe knowledge itself fashionable ; and the severe sufferings
of the Prussians previous to the war, by which themselves and
Europe were freed, have impressed on them so strongly the
lesson that " knowledge is power," that its effects are visible
in every department of the government ; and there is no coun-
try in Europe in which talents and genius so surely open for
their possessors the road to wealth and distinction.

Another circumstance also contributed its portion to increase
the numbers of the meeting of the past year. The office of
president, which is annually changed, was assigned to M.
Alexander de Humboldt. The universality of his acquirements,
which have left no branch within the wide range of science in-
different or unexplored, has connected him by friendship with
almosc all the most celebrated philosophers of the age ; whilst
•the polished amenity of his manners, and that intense desire of
acquiring and of spreading knowledge, which so peculiarly
characterizes his mind, renders him accessible to all strangers,
and insures for them the assistance of his counsel in their
scietitific pursuits, and the advantage of being made known to
all those who are interested or occupied in similar inquiries.

Professor Lichtenstein, (Director of the Museum of Zoolo-
gy,) as Secretary of the Academy, was indefatigable in his at-
tentions, and most ably seconded the wishes of its distinguish-
ed President.

These two gentlemen, assisted by several of the residents at
Berlin, undertook the numerous preliminary arrangements ne-
cessary for the accommodation of the meeting.

On the 18th of September 1828, there were assembled at
Berlin 377 members of the Academy, whose names and resi-
dences (in Berlin) were printed in a small pamphlet, and to
each name was attached a number, to indicate his seat in the
great concert room, in whidi .the morning meetings took place.
Each member was also provided with an engraved card of the

Great Congress of Philosophers at Berlin. 227

hall of meeting, on which the numbers of the seats were printed
in black ink, and his own peculiar seat marked in red ink, so
that every person immediately found his own place, and knew
where to look for any friend whom he might wish to find.

At the hour appointed for the opening of the meeting, the
members being assembled, and the galleries and orchestra
being filled by an assemblage of a large part of the rank and
beauty of the capital, and the side-boxes being occupied by
several branches of the royal family, and by the foreign am-
bassadors, the session of the Academy was opened by the
eloquent address of the President.

Speech made at the opening of the Society of German Natu-
ralists and Natural Philosophers at Berlin, the 1 8th Septem-
ber 1828. By Alexander Von Humboldt.

Since through your choice, which does me so much honour,
I am permitted to open this meeting, the first duty which I
have to discharge is one of gratitude. The distinction which
has been conferred on him who has never yet been able to at-
tend your excellent Society, is not the reward of scientific ef-
forts, or of feeble and persevering attempts to discover new
phenomena, or to draw the light of knowledge from the unex-
plored depths of nature. A finer feeling, however, directed
your attention to me. You have assured me, that while, dur-
ing an absence of many years, and in a distant quarter of the
globe, I was labouring in the same cause with yourselves, I
was not a stranger in your thoughts. Yoii have likewise
greeted my return home, that, by the sacred tie of gratitude,
you might bind me still longer and closer to our common
country.

What, however, can the picture of this our native land pre-
sent more agreeable to the mind than the assembly which we
receive to day for the first time within our walls ; from the
banks of the Neckar, the birth-place of Kepler and of Schiller,
to the remotest border of the Baltic plains ; from hence to the
mouths of the Rhine, where, under the beneficent influence
of commerce, the treasures of exotic nature have for centuries
been collected and investigated, the friends of nature, inspired
with the same zeal, and, urged by the same passion, flock toge-

Baron Kumboldt's Speech at the opening of

ther to this assembly. Everywhere, where the German lan-
guage is used, and its peculiar structure affects the spirit and
disposition of the people. From the Great European Alps to
the other side of the Weichsel, where, in the country of Co-
pernicus, astronomy rose to renewed splendour ; everywhere
in the extensive dominions of the German nation we attempt
to discover the secret operations of nature, whether in the
heavens, or in the deepest problems of mechanics, or in the in-
terior of the earth, or in the finely woven tissues of organic
structure.

Protected by noble princes, this assembly has annually in-
creased in interest and extent. Every distinction which diffe-
rence of religion or form of government can occasion is here
annulled. Germany manifests itself as it were in its intellec-
tual unity ; and since knowledge of truth and performance of
duty are the highest object of morality, that feeling of unity
weakens none of the bonds which the religion, constitution,
and laws of our country, have rendered dear to each of us.
Even this emulation in mental struggles has called forth (as
the glorious history of our country tells us,) the fairest blos-
soms of humanity, science, and art.

The assembly of German naturalists and natural philoso-
phers since its last meeting, when it was so hospitably received
at Munich, has, through the flattering interest of neighbour-
ing States and Academies, shone with peculiar lustre. Allied
nations have renewed the ancient alliance between Germany
and the ancient Scandinavian North.

Such an interest deserves acknowledgment the more, be-
cause it unexpectedly increases the mass of facts and opinions
which are here brought into one common and useful union. It
also recalls lofty recollections into the mind of the naturalist.
Scarcely half a century has elapsed since Linne appears in the
boldness of the undertakings which he has attempted and ac-
complished, as one of the greatest men of the last century.
His glory, however bright, has not rendered Europe blind to
the merits of Scheele and Bergman. The catalogue of these
great names is not completed ; but lest I shall offend noble
modesty, I dare not speak of the light which is still flowing
in richest profusion from the North, nor mention the disco-

the Great Congress of' Philosophers at Berlin. S29

veries in the chemical nature of substances, in the numerical
relation of their elements, or the eddying streams of electro-
magnetic powers.* May those excellent persons, who, deter-
red neither by perils of sea or land, have hastened to our
meeting from Sweden, Norway, Denmark, Holland, England,
and Poland, point out the way to other strangers in succeed-
ing years, so that by turns every part of Germany may enjoy
the effects of scientific communication with the different na-
tions of Europe.

But although I must restrain the expression of my personal
feelings in presence of this assembly, I must be permitted at
least to name the patriarchs of our national glory, who are de-
• tained from us by a regard for those lives so dear to their coun-
try ; — Goethe, whom the great creations of poetical fancy have
not prevented from penetrating the arcana of nature, and who
now in rural solitude mourns for his princely friend, as Ger-
many for one of her greatest ornaments ; — Olbers, who has dis-
covered two bodies where he had already predicted they were
to be found ; — the greatest anatomists of our age— Soemmer-
ing, who, with equal zeal, has investigated the wonders of or-
ganic structure, and the spots and Jdculoe of the sun, (con-
densations and openings in the photosphere;) Blumenbach,
whose pupil I have the honour to be, who, by his works and
his immortal eloquence, has inspired everywhere a love for
comparative anatomy, physiology, and the general history
of nature, and who has laboured diligently for half a cen-
tury. How could I resist the temptation to adorn my dis-
course with names which posterity will repeat, as we are not
favoured with their presence ?

These observations on the literary wealth of our native coun-
try, and the progressive developement of our institution, lead
us naturally to the obstructions which will arise from the in-
creasing number of our fellow-labourers. The chief ob-
ject of this assembly does not consist, as in other societies
whose sphere is more limited, in the mutual interchange of
treatises, or in innumerable memoirs, destined to be printed in
some general collection. The principal object of this Society
is to bring those personally together who are engaged in the

* The philosophers here referred to are Berzelius and Oersted.

2S0 Baron Humboldt''s Speech at the opening of

same field of science. It is the immediate, and therefore more
obvious interchange of ideas, whether they present themselves
as facts, opinions, or doubts. It is the foundation of friendly
connection which throws light on science, adds cheerfulness to
life, and gives patience and amenity to the manners.

In the most flourishing period of ancient Greece, the dis-
tinction between words and writing first manifested itself most
strongly amongst a race, which had raised itself to the most
splendid intellectual superiority, and to whose latest descen-
dants, as preserved from the shipwreck of nations, we still con-
secrate our most anxious wishes. It was not the difiiculty of
interchange of ideas alone, nor the want of German science,
which has spread thought as on wings through the world, and
insured it a long continuance, that then induced the friends of
philosophy and natural history in Magna Graecia and Asia
Minor to wander on long journies. That ancient race knew
the inspiring influence of conversation as it extemporaneous-
ly, freely, and prudently penetrates the tissue of scientific opin-
ions and doubts. - The discovery of the truth without differ-
ence of opinion is unattainable, because the truth in its great-
est extent can never be recognized by all, and at the same time.
Each step, which seems to bring the explorer of nature nearer
to his object, only carries him to the threshold of new laby-
rinths. The mass of doubt does not diminish, but spreads
like a moving cloud over other and new fields ; and whoever
has called that a golden period, when difference of opinions, or,
as some are accustomed to express it, the disputes of the learn-
ed will be finished, has as imperfect a conception of the wants
of science, and of its continued advancement, as a person who
expects that the same opinions in geognosy, chemistry, or phy-
siology, will be maintained for Several centuries.

The founders of this society, with a deep sense of the unity
of nature, have combined in the completest manner all the
branches of physical knowledge, and the historical, geometri-
cal, and experimental philosophy. The names of natural his-
torian and natural philosopher are here, therefore, nearly syno-
nymous, chained by a terrestrial link to the type of the lower
animals. Man completes the scale of higher organization. In
his physiological and pathological qualities, he scarcely pre-
sents to us a distinct class of beings. As to what has brought

the Great Congress of Philosophers at Berlin. 231

him ta this exalted object of physical study, and has raised
him to general scientific investigation, belongs principally to
this society. Important as it is not to break that link which
embraces equally the investigation of organic and inorganic
nature, still the increasing ties and daily developement of
this institution renders it necessary, besides the general meet-
ing which is destined for these halls, to have specific meetings
for single branches of science. For it is only in such con-
tracted circles, — it is only among men whom reciprocity of
studies has brought together, that verbal discussions can take
place : Without this sort of communication, would the volun-
tary association of men in search of truth be deprived of an in-
spiring principle.

Among the preparations which are made in this city for the
advancement of the society, attention has been principally paid
to the possibility of such a subdivision into sections. The hope
that these preparations will meet with your approbation im-
poses upon me the duty of reminding you, that, although you
had entrusted to two travellers, equally, the duty of making
these arrangements, yet it is to one alone, my noble friend,
M. Lichten stein that the merit of careful precaution and in-
defatigable activity is due. Out of respect to the scientific
spirit which animates the Society of German Naturalists and
Natural Philosophy, and in acknowledgment of the utility of
their efforts, government have seconded all our wishes with
the greatest cheerfulness.

In the vicinity of the place of meeting, which has in this
manner been prepared for our general and special labours, are
situated the museums dedicated to anatomy, zoology, oryc-
tognosy, and geology. They exhibit to the naturalist a rich
mine for observation and critical discussion. The greater num-
ber of these well arranged collections have existed, like the
University of Berlin, scarcely twenty years. The oldest of
them, to which the Botanical Garden (one of the richest in Eu-
rope) belongs, have during this period not only been increas-
ed, but entirely remodelled. The amusement and instruction
derived from such institutions call to our minds, with deep
feelings of gratitude, that they are the work of that great mo-
narch, who modestly and in simple grandeur, adorns every year

232 Great Congress of Philosophers at Berlin.

this royal c}ty with new treasures of nature and art ; and what
is of still greater value than the treasures themselves, — what
inspires every Prussian with youthful strength, and with an
enthusiastic love for the ancient reigning family, — that he gra-
ciously attaches to himself every species of talent, and extends
with confidence his royal protection to the free cultivation of
the understanding.

This was followed by a paper on magnetism, by Professor
Oersted ; and several other memoirs were then read.

The arrival of so many persons of similar pursuit, for 464
members were present, rendered it convenient to have some
ordinary at which those who chose might dine, and introduce
their friends or families. This had been foreseen, and his
Majesty had condescended to allow the immense building used
for the exercise of his troops to be employed for this purpose.
One-third of it was floored on the occasion, and tables were
arranged at which, on one occasion, 850 persons sat down to
dinner. On the evening of the first day, M. de Humboldt
gave a large soiree in the concert rooms attached to the theatre.
About 1200 persons assembled on this occasion, and his Ma-
jesty the King of Prussia honoured with his presence the fete
of his illustrious chamberlain. The nobility of the country,
foreign princes, and foreign ambassadors, were present. It
was gratifying to observe the princes of the blood mingling
with the cultivators of science, and to see the heir-apparent
to the throne, during the course of the evening, engaged in
conversation with those most celebrated for their talents, of
his own, or of other countries.

Nor were the minor arrangements of the evening beneath
the consideration of the president. The words of the music
selected for the concert were printed and distributed to the vi-
sitors. The names of the most illustrious philosophers which
Germany had produced, were inscribed in letters of gold at
the end of the great concert room.

In the first rank amongst these stood a name which Eng-
land, too, enrolls amongst the brightest in her scientific annals,
and proud, as well she may be, of having fostered and brought
to maturity the genius of the first Herschel, she has reaped

Great Congress q/' Philosophers at Berlin. 2^3

an ample reward in being able to claim as entirely her own,
the inheritor of his talents and his name.

The six succeeding days were occupied in the morning by
a meeting of the academy, at which papers of general interest
were read. In the afternoon, through the arrangement of M.
de Humboldt and M. Lichtenstein, various rooms were appropri-
ated for different sections of the academy. In one, the chemi-
cal philosophers attended to some chemical memoir, whilst the
botanists assembled in another room, the physiologists in a
third, and the natural philosophers in a fourth. Each attended
to the reading of papers connected with their several sciences.
Thus every member was at liberty to choose that section in
which he felt most interest at the moment, and he had at all
times power of access to the others. The evenings were ge-
nerally spent at some of i\\e soirees of the Savans resident at
Berlin, whose hospitality and attentions to their learned bre-
thren of other countries were unbounded. During the unoccu-
pied hours of the morning, the collections of natural history,
which are rapidly rising into importance, were open to exami-
nation, and the various professors and directors who assisted
the stranger in his inquiries, left him equally gratified by the
knowledge and urbanity of those who so kindly aided him.

A map of Europe was printed, on which those towns only
appeared which had sent representatives to this scientific con-
gress; and the numbers sent by different kingdoms appeared
by the following table, which was attached to it : —

Russia,

Wirtemburg,

Austria,

Sweden,

England,

Naples,

Holland,

Poland,

Denmark,

German States,

France,

Sardinia,

•206

Prussia,

Berlin,

172

Bavaria,

Hanover,

378

Saxony,

The proportion in which the cultivators of different scien-

234 Mr Henwood on the Temperature of Mines.

ces appeared was not easy to ascertain, because there were few
amongst the more eminent who had not added to more than
one branch of human knowledge. The following table, though
not professing to be very accurate, will afford perhaps a to-
lerably fair view : —

Geometers,

Anatomy,

Astronomers,

Zoology,

Natural Philosophers,

Natural History,

-^ 39

Botany,

Mines,

— 57

Mineralogy,

Physicians,

175

Geology,

Amateurs,

— 30

Various,

Chemistry, • -

^ —

Geography,

381

A medal was struck in commemoration of this meeting, and
it was proposed that it should form the first of a series, which
should comprise all those persons most celebrated for their sci-
entific discoveries in the past and present age.

The free interchange of knowledge between the members of
such an assembly did not fail to produce beneficial results.

Amongst the persons present were.

Berzelius,

Von Buch,

Hufeland,

Oersted,

Humboldt,

Reinwardt,

Gaus,

Ehrenberg,

Mitscherlich,

Babbage,

Heusinger,

Rose,

Von Martins,

TromsdorfF,

Dobereiner,

Encke,

Oltmans,

Wohler,

Seebeck,

Crelle,

Link.

Oken,

Art. IX. — A Summary of Experiments recently made on the
Temperature of Mines. By W. J. Henwood, Esq. F. G. S.,
Member of the Royal Geological Society of Cornwall.
Communicated by the Author.

It appears that Mr R. W. Fox, and his friend, Mr Lean of
French-hay, but then resident in Cornwall, were the first per-

Mr Hen wood on the temperature of Mines. 235

.•sous whose attention was directed to this subject. At their
request, Mr Thomas Lean, brother of the latter, and then agent
;at Huel Abraham Mine, was requested to make some experi-
ments on the temperature of that mine, of which he forwarded
Jthe results to Mr Fox ; although he subsequently published
them, * before the communication of Mr Fox''s paper on the ,
*feame subject, to the Cornwall Geological Society in 1819 "f*.
rlti this paper, Mr Fox inserted these and other experiments,
•made about the same time in various mines, and insisted on
the general fact of an increase of temperature at considerable
depths in the earth.

^ At the same meeting of that society, a paper on the same
Subject was communicated by John Forbes, M. D. J ; but al-
though they agreed in the facts which had been adduced, his
•kiferences were different, indeed opposed to those of Mr Fox, as
to there being evidence of a native heat of the earth itself. The
observed elevation of temperature he attributed to the presence
of workmen, combustion of candles, &c. and in support of this
opinion he entered into elaborate calculations. His subse-
quent inquiries led him to a different conclusion ; and in a se-
cond memior, read to the same society in 1820, he admitted
the existence of a terrestrial heat, independent of adventitious
circumstances ; although he still thought the observed eleva-
tion of temperature was materially affected by these causes.
This gentleman's publication contained the facts in both these
papers, but not the conclusions which appeared in the first of
them.

A second communication from Mr Fox was laid before the
society at the same meeting, in which many more observations
were adduced in support of his original conclusions §.

In 1819, Mr Bald's observations on the temperatures ob-
served in some of the coal mines in the North of England were
laid before the Koyal Society of Edinburgh ||, of which the

• Phil. Mag. xlii. 204.

t Cornwall GeoL Trans, ii. 14; Annals, N. S. xxii. 41 ; and Phil.
Mag. Ixi.

% Cor-nwall G. Tram: ii. 159 ; Annals, xxii. 447 ; and Phil. Mag. Ixi. 436.
§ Cornwall G. Trans, ii. 19 ; Annals, xxii.; and Phil. Mag. Ixi.
II Edin. Phil. Journal., I 134 ; and Phil. Mag. Ixii. 105.

236 Mr Hen wood an t/ie temperature of Mines.

results nearly coincided with those of the observations made in
Cornwall. In 1822, Mr M.P. Moyle read to the Cornwall Geo-
logical Society a paper on the same subject, strongly opposing
the idea of a high internal temperature, * having previously
done so in the Annals of Philosophy. The other papers which
have appeared on this subject are by Dr John Davy -f*, Mr
Fox J, Mr Moyle §, and Dr Barham||. It appears from Mr
Fox's observations, that the mean temperature of the mining
district in the vicinity of Falmouth is 49.86. ^f " The wa-
ter pumped from the Gwennap Mines is conveyed through
different branch adits into a large adit or tunnel," the tempe-
rature of the stream passing through which, near the point of
its discharge into the Carnon Vale, is 69°.25, the quantity
being computed at 60,000 tons per day. In one of the branches
in which the water is conveyed from the United, the consoli-
dated and other mines, of which the average depth may be
estimated at 150 or 160 fathoms, the temperature of the water
is 73°.5. G^°5 is the temperature of the water in a second
branch, which leads from Poldice, Huel Unity, Huel Gorland,
and other excavations, estimated at a mean depth of 1 10 or 120
fathoms ; whilst a third division, proceeding from Treskerby,
Huel Chance, and other mines, of about an average depth of
100 or 110 fathoms, contains water at 65!^. Dr Forbes states,
that when the depth of Huel Neptune Mine was 90 fathoms,
the temperature of the water discharged at the pump head was
60° ; an increase of 36 fathoms subsequently obtaining in the
depth, an elevation of the temperature of the water to 62° was
the consequence; and that an increase of 17 fathoms in the depth
of Botallack Mine augmented the temperature of the water 5°.
Mr Fox informs us, that an accident to the machinery at Ting
Tang Mine occasioned an accumulation of water at the bot-
tom, which was then 117 fathoms in depth. When within ten
fathoms of the bottom, the temperature of the liquid was 63°. 5,
whilst that drawn from the bottom was at Qo^. The following

• Cornwall G. Trans, ii. 404; Annals, xxii. and Phil. Mag. Ixii. 94.

•j" This Journal, vol. iii. 75.

X Annals, xix. 381, Cornwall G. Trans, iii. 313. and Phil. Mag, Ixii. 58.

§ Annals, xix. 308 — 415; xxi. 35. xxiv. 446, xxvi. 259.

II Cornwall G. Trans, iii. 150.

IT This Journal, vol. x. p. 118.

Mr Hen wood on the temperature of Mines.

237

table contains a selection of such observations as have been
made on the temperature of water immediately, or at a very
short interval after it had gushed from the rock.

Place.

Depth in
fathoms.

Well at Southwark, *

South Towan Mine. S.

Welhngton. S.

Oatfield. S.

Liscombe,

Unity Wood,

Huel Trumpet. G.

Botallack. G,

115

Ting Tang. S.

117

Beer Alston,

120

Trumpet. G.

128

Chacewater Mine. S.

128

Huel Vor,

131

Poldice,

144

Consolidated,

150

Huel Alfred,

155

Huel Friendship,

170

United Mines,

170

180

Stray Park,

200

Oatfield Mine. S.

236

Dolcoath Mine. G.

240

" Not only'^ (observes Mr

Fox) '

Temp.

Observers.

54°

Fox.

Moyle.

Fox.

Moyle.

Barham

Fox.

66.5

Moyle.

Fox.

Forbes.

Fox.

64.5

87.5

Moyle.

86.5

Fox.

are the gushing streams
at great depths generally warmer than the water or the air in
the shallower parts of mines, but they are not unfrequently

* Mean Temp, of London 49°.5, Howard. The letters G and S denote
the mine being in granite or slate (primitive clay.)

238 Mr Hcnw(X)d on the temperature of Mines.

more so than the air which surrounds them.''* The truth of
this assertion will be seen from the following comparison of
the temperatures of air and water in various mines, and at
different depths.

Place.

Little Bounds Mine,

Huel Vor, i

Little Bounds,

Wellington,

Botallack,

Ding-dong,

Chacewater,

Huel Vor,
Huel Abraham,

Stray Park,
Dolcoath,

Depth in
fathoms.

Temperature,
Air. Water.

Observers.

54.°

54.<'

Forbes.

at 40

Barham.

Forbes.

58.5

(57

(58

Fox.

Forbes.

108

128

Fox.

140

Forbes.

140

70.£

\ 73.5 Fox.

200

78.5

2p0

J 72
(74

240

r80

(82

It is admitted by all parties, that the temperature of such
parts of mines as are wrought by many men without a free cir-
culation of air, is somewhat above that of the water, and of
the air in properly ventilated stations, excepting, perhaps, at
or near the bottom of deep mines, notwithstanding the influ-
ence which the copious ascent of vapour constantly obtaining
must exert in diminishing the temperature of the lower por-
tions, and elevating that of the shallow ones. On examining
the directions of the aerial currents in 25 of the principal
shafts of Dolcoath mine, Mr Rule found them to be descending
in 13, and ascending in the others. But a change in the
direction of the wind reversed that of the currents in some of
the shafts, and other parts of the mine. Having been favoured
with a sight of some of Mr Fox's communications to a scien-
tific friend on this subject, I am permitted to make some in-
teresting extracts relative to the influence of the seasons on the

Mr Henwood 07i the temperature of Mines. 239

temperature at considerable depths, &c. In Fig 8. Plate II.
which refers to Dolcoath mine*, A is the bottom of the engine
shaft, 235 fathoms deep ; B,C the deepest galleries or levels
on the course of the vein at 230 fathoms deep ; D E galleries
220 fathoms deep on the same vein. A great portion of the
water finds its way to A, whence it is pumped by a steam-en-
gine, the quantity discharged at the pump head in 24 hours
being estimated at 500,000 gallons. At «, a stream at the
temperature of 82° issued, and at e, a smaller one at 78°, the
air near A being at 80°. These results were obtained at inter-
vals of some years. A hole, three feet in depth, was made at
o in the deepest level, 15 fathoms from the engine shaft. It
was usually quite dry, and for some years no men had been
employed nearer to it than at A. In this hole was inserted
the bulb of a thermometer, four feet in length, the space
round the lower extremity of the instrument being carefully
filled with clay. The persons employed below DE were usu-
ally two, and occasionally three at a time, on an average say
2J constantly. In DE there were four or five at a time.

In the galleries, 10 fathoms higher up, 10 men at a time,
^ " Do. 10 do. 14 do.

Do. 10 do. 14 do.

The total number of men was 360, but as each worked only
six- hours at a time, say, equal to about 100 constantly in the
mine.

The thermometer, which was placed at o in January 1821,
being taken up in September 1822, did not seem to be affected
by the seasons ; but the influx of water into the gallery, which,
in consequence of the stoppage of the machinery, sometimes
took place, caused the mercury to rise a little, to the extent of
1° or l.°5, the observations being made as soon as the station
became again accessible. At other times the temperature was
75° to 75.''5. A thermometer, buried eight inches in the rock,
at different stations, in many of the superior galleries of this
mine, that nearest to the surface being 100 fathoms deep, in-
dicated temperatures varying, according to the depth, from

* The experiments here detailed were made before the shaft was sunk
so deep as 240 fathoms, mentioned in the preceding tables.

240 Mr Hen wood on the temperature cf Mines,

57 °5 to 70°. The surface of this mine is about 62 fathoms
above the level of the sea, the deepest workings being in gra-
nite, and those nearer the surface in clay-slate. The Tres-
kerby mine is worked under circumstances of strata and eleva-
tion very similar to Dolcoath. In December 1819, the tem-
perature at the surface being 50°, those of two streams pro-
ceeding from the opposite extremities of the deepest gallery,
149 fathoms below the surface, were 72° and 76°. The tempera-
tures of these streams were precisely the same in January 1 820,
that at the surface then being 30°. In September 1820, the tem-
peratures of the streams were respectively 73° and 76°, the air
at the surface being at 67° The galleries nearest to the sur-
face are almost universallv more extended than those at ffreat
depths, consequently affording space for the employment of a
greater number of labourers ; and this being invariably the
case, were the high temperatures prevailing in mines due to
their presence, the shallower levels would be much warmer
than those at considerable distances beneath. Moreover, the
tin, copper, and other veins, as well as the arrangement of
stratification in Cornwall, approach nearly to a perpendicular
direction. As a consequence, the water from the surface and
superior parts of mines descends to the inferior excavations.
Thus every mine drains the neighbouring district to a consider-
able extent, not unfrequently to a distance of two, three, or
even more fathoms in length for every fathom in depth. Hence
it would seem that the temperature of streams, when gushing
from the rock, is probably below that of the earth at that
depth. In opposition to the facts and arguments in favour of
an internal terrestrial heat, considerable stress has been laid by
Mr Moyle on the comparatively low temperature of the water
accumulated in abandoned deep mines. The substance of the
greater number of observations on this division of the subject
is included in the following table : —

Place.

jL»epm 111
fathoms.

Temp.

Observers.

Alverton, (well,)

Surface.

55.5°

Dr Dav

Huel Maid Mine,

Marazion, (well,)

Huel Fortune Mine,

55.5

Mr Hen wood on the temperature of Mines.

241

Pkce.

Depth in
fathoms.

Temp.

Observers.

Huel Fortune

Mine, an-

other shaft.

56°

Herland,

Moyle.

54*

Huel Rose,

OllCiXt/,

53.5

Trevenen,

Kuel Alfred,

Relistian,

25)
50 j

Huel Rose,

Little Bounds Mine,

Forbes.

Botallock,

Ding Dong,

5%5

Huel Alfred,

112

Moyle.

Huel Vor,

115

Forbes.

Tresaveax,

100

Fox.

Gunnis Lake,

125

United Mines,

170

Oatfield,

182

Moyle.

That the veins are much more pervious to the passage of
water than the contiguous strata is a notorious fact ; and I
have before alluded to the greater extent of the superior than
of the inferior galleries. It therefore appears that the great-
er portion of water coming from above is probably intercepted
by the superior galleries, and passing through them to the
shafts, if of a relatively low temperature, descends. It may
be presumed that the water in the lower levels, being compa-
ratively stationary, exerts but little influence on that in the
shafts ; of which, however, it appears that we might expect to
find the temperature invariable at all depths. But we must
not forget that the mean temperature of wells, and at the sur-
face in stopped mines, is somewhat more than five degrees
above the mean of the climate ; and that in some mines, in the
lower levels of which operations have been suspended, and ac-
cumulations of water permitted, the temperature is very far
above 49.°86, as reference to the preceding table affords ample
evidence. On this part of the question Mr Fox remarks, " the
* The water at 10, 20, 40, and 60, fathoms deep was also at 54.°

VOL. X. NO. II. APRIL 1829- Q

242 Mr Hen wood on the temperature of Mines.

effects are doubtless variously modified in different places by
the nature and thickness of the strata, and the more or less
pervious state of the veins ; besides, the workings communicat-
ing with the shafts are in some mines much more open and
excavated than in others ; and, considering all these circum-
stances, we might anticipate that the results of experiments on
the temperature of water in stopped mines must be discordant
and inconclusive as to the actual heat of the earth itself, how-
ever strongly they may corroborate the truth of its existence."
In connection with this part of the subject it may be men-
tioned, that the stopping of one of the engines at the united
mines permitted the accumulation of water in the two deepest
galleries, viz. 190 and 200 fathoms deep, which continued for
two days. Immediately on its being pumped out, and before
the mines had resumed their operations, the temperature of
the upper one was 87°.5 and of the lower 88°. The observa-
tions being repeated some days after the workmen had recom-
menced operations, the temperature was found to have rather
diminished than otherwise. The same conclusion, resulting
from various views of the subject, seems to put the fact be-
yond dispute, although it does not appear that the ratio of in-
crease can be so readily determined. Notwithstanding some
few insulated facts had been previously noticed by other philo-
sophers, it will be seen from the preceding observations that
to Mr Fox we are indebted for the first annunciation of the
general law, as well as for a great portion of the information
which has now so satisfactorily established its accuracy. That
the matter was thus correctly viewed on the continent, he had,
in February 1820, the satisfaction of learning from an eminent
French philosopher, who observes, that *' Baron Humboldt,
who had previously noticed similar facts in the mines of Mex-
ico, and who then attributed the augmented temperatwe to ac-
cidental causes, since the experiments of Mr Fox have been
communicated to him, unites in the opinion, that this increase
of heat in the interior of the earth is a general fact, and not
dependent on local circumstances. He wished that the expe-
riments should be multiplied, and that, by keeping them as
free as possible from all disturbing influences, the question
might be placed beyond doubt.'' The influence of this im-

Mr Hen wood on the temperature of Mines* 243

portant principle seems to affect the preservation of vegetable
life, by protecting the roots of plants from the rigour of the
winter's cold^ and in summer preventing their being parched
by the intensity of solar heat. That evaporation obtains at all
times, even in the severity of winter, may be readily ascertain-
ed by the inversion of a glass over a spot from which the fro-
zen earth has been removed. The conversion of this vapour
(which, by parting with its caloric, must mitigate the severity
of the cold to plants,) must also materially operate on the at-
mosphere. Indeed, many meteorological phenomena seem inti-
mately connected with this subject. The condensation of va-
pour in hills and elevated stations must be the principal, if noj;
the entire, cause of the formation of springs.

The source of this moisture is another object well deserving
attention. It does not seem probable that the atmosphere can
be the only one. Some of Mr Fox's discoveries seem to af-
ford us light in the inquiry. He observes that the relative pu-
rity of the water seems to have no reference to the tempera-
ture or depth of the mines. The deposit from the water from
Huel Abraham and Dolcoath, the two deepest mines in Corn-
wall, did not in either case exceed two grains from a pint,
whilst that from the consolidated mines yielded, from a like
quantity of liquid, ten grains ; from Huel Unity, 16 grains ;
from one shaft in Poldice, 19 grains ; and from another,
92 grains. The salts most abundantly afforded by evapo-
ration are the chlorides, especially that of calcium, although
Mr Fox has frequently detected the presence of chloride of
sodium, particularly in the water from the united and consoli-
dated mines, Huel Unity and Poldice. Of the 92 grains from
the latter, 52 grains were of the chlorides of calcium and mag-
nium, 24 grains of the chloride of sodium, the remainder be-
ing muriatic acid, with iron and sulphate of lime. The water
from another part of the same mine afforded, by the evapora-
tion of the same measure of water, 5.5 grains of the chloride
of calcium. " All these mines are in killas, or primitive clay-
slate, and are several miles from the sea."" From such facts
may it not with propriety be inferred, " that the sea- water pe-
netrates into the fissures of the earth, and may, in a greater or
less degree, assist in supplying the loss of moisture by evapora-

244 Mr Hen wood on the temperature of Mines.

lion ?" Mr Fox is disposed to think that the isothermal Hnes
within the earth may in some measure coincide with the form
of its surface.

Another point to wliich attention has been directed is the re-
lative temperatures of the metalliferous veins, and the adjacent
strata at some distance from them. Of these observations the
followintr table contains the substance.

Mine.

Depth.

Distance from the
veins at which obser-
vations were made
in the strata

Vein.

Little Bounds,
Huel Neptune,
Ting Tang,

30 fathoms.

Huel Squire,
Chacewater,
Treskerby,
Dolcoath,
United Mines, 140
160

52 Unoticed.

110

110
1^.0
130

Temperature.*
Strata.

54iW

j 54° w? \
\56w J

Observers.

Forbes.

unnoticed.

60 fathoms.

9 —

64 e
68 e

S2e

72 a
6Se
67 w

75 e

}

64 e Fox.

69 fl
79 a

66 a
62 e

67 e
69 e

An obvious inference is, that the temperature of veins is
generally rather superior to that of the contiguous strata. The
subject of the temperature of the interior of the earth has led
to many ingenious theories of its structure and relations.
Among these, that which supposes the central regions to exist
in a liquid state, subject to the action of a very elevated heat,
seems to be gaining ground. Were the high temperatures ob-
served due to such agency, it would naturally be expected
that the closer the texture and the better the conducting power
of any given substance, the greater would be the elevation of
temperature observed therein. But casteris paribus, our granite
and porphyriiic rocks, although far surpassing clay-slate and
metalliferous veins in both these circumstances, are generally
found at a lower temperature than any other of our strata or
formations. Mr Fox remarks, that the high temperature " may

' * Of the letters, a signifies that the experiment was in the air, e the
earth, and w the water.

No. III. — Pausiiipo and the Lago (TAgnano. 245

perhaps be attributed to the circulation of water and vapour
ascending from greater depths ; and if this be the case, it may
be difficult to arrive at any just notion of the extent of the
progressive increase of the heat in the interior of the earth,
from observations made at any depth now accessible." On the
exciting cause of the caloric requisite for the formation of
vapour, &c. it would, in the present state of the investigation^
be premature to speculate. That electricity may be an active^
agent does not seem improbable ; and to a detail of some facts
in support of this opinion I may, on some future occasion, al-
low myself the pleasure of returning.

Art. X. — Physical Notices of the Bay of Naples. By James
D. Forbes, Esq. Communicated by the Author.

No. III. — On the District of Pausiiipo and the Lago d^Ag-

nano.

" Pausilypi coUes, et Candida Mergeliina,
Et myrteta sacris consita littoribus

Me tibi, terra beata, dico ■ "

Flaminius.

\V E have already noticed the great active volcano which forms
the leading feature of the Bay of Naples, and the cities which
fell a prey to its early ravages. Proceeding now westward,
according to our plan in this paper, we shall consider the most
prominent features between the hill of Pausiiipo and the ex-
tinct crater of Astroni, including the lake Agnano and its in-
teresting environs. The succeeding number of these notices
I intend to devote to the Solfatara ; the one following to the
temple of Serapis at Pozzuoli, and the curious natural facts
which it illustrates, and which have so long perplexed natura-
lists : I intend next to proceed with an account of the Monte
NuovOjLakeAvernus and its vicinity; and lastly, to add a notice
upon the Islands of Procida arid Ischia. We may then in a
concluding paper, take a view of the ground we have passed
over, and the general conclusions which may be drawn from a
survey of this interesting district.

In the meantime, we proceed with the objects of our pre-

246 Mr Forbes's Physkal Notices of the Bay of Naples.

sent inquiry. Immediately to the west of the town of NapleS
lies the fertile and beautiful hill of Pausilipo*, a ridge of vol-
canic tufa, somewhat steep on both sides, but exhibiting on
the top a flat appearance and saddle-shaped stratification.
Nothing of its kind can be more truly delightful, than the
drive along the Strada Nuova, or new road formed by Murat,
the late Governor of Naples. It keeps nearly at an equal dis-
tance from the sea, which washes the base of the hill as it gra-
dually declines to the southward, and, acting upon the soft
rock, of which it is composed, has rendered it every where
somewhat precipitous, and here and there beautifully pictur-
esque, from the fantastic masses it has detached from the coast,
and the water-worn caves and arches through which here and
there it rolls. The trifling tides do not prevent the high luxu-
riance of all vegetable nature from descending almost to the wa-
ter ; every flat patch is assiduously cultivated for the vine, and
the richest wild shrubs clothe every rock and crevice. The aloe
especially, throws out its long and thorny leaves, either where
it has naturally taken root, or where it has been planted to
decorate and diversify the villas and casinos of the Neapoli-
tans, which thickly spread over the banks and dells of this fa-
voured promontory. The glowing scene in the foreground,
with all the retiring bays and salient points of Pausilipo, con-
trast finely with the majestic summit of Vesuvius rising across
the bay, and the more distant ridge of the Apennines, stretch-
ing in perspective from the central part of Italy to their bold ter-
mination in Minerva's Point. Nearer on the left, the busy and
populous city of Naples, spread in glorious array upon the thea-
tric station which it occupies, and crowned behind by the im-
posing batteries of the castle St Elmo, which rise upon the
summit of the hill behind. Dead must that soul be to all the
magnificence and luxuriance of nature, which has not caught
a glow of enthusiasm upon the shores of Pausilipo I

• This name is derived from the ancient one of a Villa of Vedius Polh'o
on this promontory, which lie called Pausilypum from its care dispelling
heauty and seclusion; {reivct and xwoi) and all will to this day admit the pro-
priety of the appellation. It is now written Pausilipo, Pausilippo, or some-
times Posillipo. I have here adopted the first as being more consonant to
the original orthography, though Pausilypo would be more strictly accurate.

No. m.-^-Paiisilipo and the Lago tVAgnano. 24f7

The country houses which we have already mentioned arc
curiously contrasted with some dwellings of the lower classes,
which appear on the mountain side of the road., They are
excavated from the mass of soft and homogeneous tufa, with
the proper accompaniments of doors, windows, and chimneys.
An amusing example of this will be recollected by those who
have visited the " Villa Barbaia," which once belonged to the
king of Naples, and where the excavations are extremely fantas-
tic. The extreme facility with which this stone is cut has given
rise to extraordinary subterranean quarries, by which the inter-
nal constitution of the hill is interestingly shown, as we shall
presently have occasion to notice.

As we continue along the Strada Nuova several sections
meet the eye, through which the road passes, too remarkable
not to attract the most superficial observer. At the west ex-
tremity of the ridge, where it abruptly falls into the plain be-
low, a cut of considerable depth has been made. Here we
have an admirable contrast of the superficial strata to those
constituting the centre of the tufaceous mass, and which is
elsewhere exposed. The layers succeed each other with great
regularity and sharpness. They are composed of various alter-
nating volcanic conglomerates, in which the common pale yellow
tufa predominates, replaced by pumiceous compounds of va-
rious shades of colour, some of which are so friable as to re-
quire to have the space their thin stratum occupied built up
with stone and lime, to support the more consistent forma-
tions, as the angle of section on both sides of the road is very
steep. The whole presents a very curious appearance. The
form of the stratification deserves particular remark. It is by
no means uniform, but bears the most irresistible marks of di-
luvial deposition. In most cases, it is gently undulating, not
unlike the newer deposits of sand which so abundantly occur
near Edinburgh, but usually still more irregular. Superim-
posed on this stratification, there often occurs a perfectly ho-
rizontal one, filling up the basins caused by the undulating
surface with dark, thin, and friable deposits. The whole ge-
neral line of the strata is conformable to the shape of the hill,
as far as I have observed, but the thin depositions just de-
scribed occur only on the flatter part, and seem awanting at

248 Mr Forbes's Physical Notices of the Bay of Naples.

the sides of the ridge which I have already remarked descend
abruptly to the plains. This is more particularly the case at
the western side of the hill, where it is so remarkably steep
that the road has been carried down by a long oblique tra-
verse, where the soft rock is obliged to be so steeply cut
away, that every winter accidents happen by the rains.

This steep and elevated portion of Pausilipo stretches bold-
ly into the sea, and the contorted chasms formed in its shores
by the waves afford many picturesque subjects for the pain-
ter. A little out to sea, in the line of the ridge, and obvious-
ly separated from it either by some convulsion of nature or the
slow operation of time, rises the small island of Nisida, and be-
tween it and the shore a fragment of rock on which a Laza-
retto is built. The island is most picturesquely green, and
has the appearance from the land of perpetual spring. It is in-
teresting in a geological view, from the perfect remains of a
volcanic crater it displays, filled with water, and communicat-
ing by a breach to the south-west with the sea : it forms the
harbour, and is named Porta Pavone. Nisida is composed of
tufas, apparently similar to those of Pausilipo, and detached
lavas also occur, which may be referred to the eruptions of the
extinct crater. A beautiful and characteristic view of the har-
bour is given in Hamilton'^s Campi Phlegrcci^ Plate xxii.

By the fortuitous excavation of the grotto of Pausilipo, a
subterranean passage of near half a mile through the heart of
the hill, we have the rare advantage of a geological section at
a great depth below the surface of the earth. Though in this in-
stance it happens that there is almost no variety to be exhibit-
ed in the nature of the rock, yet we could not otherwise have
been assured of this interesting fact. The darkness of the
grotto renders it difficult to examine the structure of the moun-
tain ; but Spallanz^ni observes, * that, when viewed by the
morning sun, when it penetrates the grotto, the tufa is dis-
tinctly stratified, and evidently by the action of water, — a fact
now rendered far more distinct by the frequent alternations in
the sections on the upper part of the hill. What I believe
has sometimes been taken for stratification, is nothing else
than the grating of the wheels of vehicles against the sides in
* Travels, i. 43.

No: m.^-^Pausilipo and the Lago cCAgnano. 249

former times before the road was lowered, yet there seems no
doubt that some divisions of strata do occur, as is seen at the
east end before entering the lofty arch. * At either end are
vast ([uarries, and, as far as the light penetrates, we have an
opportunity of admiring the lofty faces of homogeneous tufa
which are exposed. In making these excavations, several inte-
resting objects have been discovered, particularly wood and
shells ; the latter I have noticed in Hamilton's Campi Plde-
grcei, since writing the last of these notices, f are actually the
shells of fish inhabiting the Bay of Naples at present, parti-
cularly oysters, — a very curious fact, which is confirmed^by Mr
Scrope in a paper read before the Geological Society J.

The history of this singular work of art mounts to the ear-
liest ages of tradition. It appears originally to have been
formed by the Cimmerians, the mysterious original inhabitants
of the district, and afterwards employed, probably enlarged,
by the Romans. By them it was named the " Crypta Pu-
teolana," and is several times mentioned by classic authors §.
Its total length is 2322 English feet, or not far from half a
mile; it is 22 feet wide ; and its height is generally from 70 to
90, but at the west end only 10. This arises from the cut
towards the opposite extremity, made in modern times to ren-
der the rise uniform, and was performed by Alphonso I. of
Arragon, || by whom the shafts from above, in one or two
places which had existed in ancient times, as we learn from
Strabo, ^ were cleared out for the admission of air, which is
very necessary, as even now the central part of the grotto is
oppressively ill ventilated. It is well known that towards the
end of October, the sun, when nearly setting, shines directly
through the grotto. Assximing then his declination — 13^ S.
on the 26th, his azimuth, when 5° above the horizon, which
we may allow partly for the elevation of the west end of the
grotto, will be 69° W : the direction, therefore, of this passage
is very nearly W. S. W. With regard to its primaeval use,

. " Hamilton, Plate xvi. f Last Number of this Journal, p. 126, note.

J Philosophical Magazine, New Series, i. 388.
, § Seneca, Ep. 38. Strabo, lib. iii. Petronius Arbiter.

II De Jorio, Guida di Fozzuoli. p. 19.

•IT Cluverius, Italia Antiqua, vol. ii. folio.

^0 Mr Forbes's Physical Notices of the Bay of Naples.

it would be bold to give an opinion ; but till the formation of
Murat's new road, it formed the only communication between
Naples and Pozzuoli and its neighbourhood, and is still the
shortest. At the end next Naples, raised far above the road,
by its subsequent reduction of level, stands the sepulchral mo-
nument dedicated by the voice of tradition, and by the opi-
nion of most modern literati to the shade of Virgil. I dare
only mention its existence, for to enter on the proofs of its au-
thenticity even in the slightest degree would carry me too far
from the object of these pages. *

Following up the ridge of Pausilipo further from the sea,
we find it divide into two circular sweeps, one of which forms
the theatrical back-ground upon which part of the town of
Naples stands, and is surrounded by the Castle of St Elmo,
while the other, stretching westward, terminates in the hill
on which stands the Convent of the Camaldoli di Napoli,
which, by a barometrical measurement by Saussure is 1419.5
French feet above the sea, equal to 1513.0 English, which is
the highest point to which the tufaceous formation rises in this
neighbourhood. The ride from Naples is truly delightful,
the ascent of the hill being gradual when we keep the
summit of the ridge, which is abundantly clothed with olive,
ilex, and copse-wood of the chestnut, which is grown here
for fire- wood. When we reach the summit, all labour taken
in the ascent is amply repaid by the surprising extent and
interest of the prospect; for here we find ourselves in the
midst of the Phlegraean fields, which, from the height of
the eye, lie pictured below us in all their true relations,

• In connection with these remarks on the Grotto of Pausilipo, I can-
not help mentioning a discovery which is said to have been made in the
part of the hill which I described as descending very rapidly a short way
from the sea, and near the Island of Nisida. On the left hand of the road
where the hill is abrupt, the opening of a passage into it is observed.
This was explored a few years ago, and is little higher and broader than a
man. The party, headed by a man of rank at Naples, penetrated a long
way with torches, till they came to a chamber containing a fine spring of
water, and seats in the rock, with bones of large animals strewed about.
They explored the remainder of the passage for a long way, and at last
came out at the other side of the hill. This I learned from a Neapolitan,
who said he had been of the party ; but I cannot vouch for its accuracy.

No. III. — Pausilipo and the Lago cCAgnano. S51

magnitudes, and bearings. To gain a true idea of the ar-
rangements of this wonderful district, nothing can be more
proper than a visit to the Camaldoli : from it we have a
view of at least fifty miles in one direction only, that of Ter-
racina. In constitution, the ground over which we pass to
this convent, resembles much the upper strata of the hill of
Pausilipo, and is particularly pumiceous, the beds varying in
colour, but little in composition, and invariably friable and
harsh to the feel, showing few of the characters of the tufa,
which probably constitutes a great part of its mass, as it does
of that part of the ridge with which it is connected, and indeed,
it is seen to alternate with the pumiceous strata ; and the lat-
ter are found divided by others, in which clay and sand are
mixed with the pumice. Indeed, I have remarked in my me-
moranda of this interesting excursion, that part of the beds
resemble so strongly simple formations of alkivium, that, to an
unpractised eye, it requires the sense of touch to prove that the
materials are harsh volcanic cinders, which so remarkably as-
sume the characters of alluvial deposits. This marks unequi-
vocally the true origin of these tufaceous mountains ; and it
may be proper here to say a word or two on the subject,
though some time hence, when treating of the theoretical con-
clusions to be drawn from the physical appearances of the Bay
of Naples, we shall have an opportunity of considering it with
more connection.

Enough has been already said in this and my last paper, to
show how much facts tend to prove, in the vicinity of Naples,
that the volcanic agency has been combined in these formations
with all the peculiarity of subaqueous deposits. Indeed this is
one of the very few points on which geologists are pretty
generally agreed, and Nature has seldom written the history
of her revolutions in former ages in more legible characters.
When I first viewed these formations myself, and endeavour-
ed, though with the eye of a novice, to compare them with
those in the Campagna di Roma, before I was initiated into
the doctrines of more profound observers who had preceded
me, by a separate track I gained the same general conclusions,
and saw spread before me in the fields of volcanic fire, proofs
that nature had performed these great acts of creative energy

252 Mr Forbes's Phijslccd Notices of the Bay of Naples.

by submarine eruptions. The fact, that the ocean once wash-
ed the foot of the Apennines at Capua, since suggested by
Scrope, appeared then to me the inevitable conclusion from
the state of facts ; and that Vesuvius has gradually raised itself
by successive accumulations to its present character, and proud-
ly surveys the regions of its own creation, is a simple induc-
tion from an attentive view of the physiognomy of the coun-
try. The minutiae of those localities under our present re-
view, are best calculated to explain plausibly the mode of for-
mation, though in this I shall be disposed not to go so far as
Breislak has done, and even to dissent somewhat from his doc-
trines. This geologist was an indefatigable crater hunter, and
he has often strengthened most palpably the features of his
maps, to writhe the most gentle and detached rising grounds
into portions of the boundaries of vast basins. This is most
conspicuous in his Plan Physique de Rome, * as may be seen
by comparing it with any good map of the city, where anti-
quaries, for the honour of the seven hills, are not usually averse
to mark strongly the inequalities of the surface. About 80
craters have been put down by Breislak between Naples and
the point of Misenum, and he freely acknowledges the strength
of imagination necessary to decypher some of them. He even
admits the preconceptions which aided him in finding a crater
in every group of hills, however large, distant or undefined.
But, according to my idea of subaqueous formation, there is
no occasion for the number of craters he supposes, and per-
haps we should be nearer the truth were we to reduce the num-
ber to a dozen. The points of emission of fluid tufa under
water would naturally be below the hills formed by it ; the hol-
low of a crater is caused by the eruption of the materials which
once filled it, into the air, and the emission of streams of lava
from its sides ; but this would not be the mode of action un-
der the sea. If the volcanic materials were ejected through
extended fissures formed by the elastic force beneath, and after-
wards modified by the action of the waves, we shall have the
exact result which the hill of Pausilipo, for instance, would
seem to afford. This will account at once for the varying di-
rections and obvious ramifications of the hills which Breislak

• See Campanie, torn. ii. and Daubeny on Volcanos.

No. III. — Pausilipo and the Lago cVAgnano. ^53

sought for only in aboriginal craters, since they were not
readily accounted for by the abrading influence of the water.
Craters no doubt may be found prior to the retirement of the
waters, according to this theory ; but they are extremely bro-
ken down, and low, and imperfect in their outline. Such we
may conceive to have been the case with the basin in which
the Lake of Agnano lies, and perhaps that of Avernus ; but as
to the scarped craters of Astroni, Solfatara, &c. I believe I
am not singular in thinking that they owe their present fea-
tures to eruptions subsequent to the elevation of this district,
or the lowering of the level of the water ; which action is most
probable I shall not here consider. It is at least certain that
Solfatara was in eruption in the 12th century, which proves it
in that particular.

Respecting the hill of Pausilipo, of the features of which I
have given some account, it seems especially to answer to the
supposed course of nature above proposed. Its interior solidity
answers well to the supposition that it was the substratum of
a great elevated fluid mass, while the more refined and pumi-
ceous substances are disposed in strata on the top. In as far
as these strata follow the shape of the hill, we may be disposed
to admit that they were first deposited, and the elevation of
the subjacent mass then took place ; and we may observe, that
the features of the hill quite unfit it for a portion of the wall
of a great crater extending to Agnano, as Breislak supposes.
He has completely perverted the form of the promontory, by
giving it a turn to the westward ; instead of which, in reality,
its line of direction makes it tend to the island of Nisida ; and
the small hill of Sta. Teresa, which he enlists as a fragment of
this degraded crater, is far liker a small regular crater of itself.
Besides all this, the hill of Pausilipo will not bear the test of
the most established rules, as to the true designation of a volca-
nic crater. Daubeny judiciously remarks, I think from Von
Buch, that a true crater has all the lines of its stratification
directed to the apex of the cone which would be formed, were
the hill complete ; but we have seen how totally inconsistent
the spot before us is with such a supposition, being both inter-
nally and externally of a flattish saddle-shaped stratification.
With these few remarks, which will convey my general ideas

254 Mr Forbes's Physical Notices of the Bay of Naples.

of submarine volcanos, I shall at present content myself, hoping
at a future time ^to recur to the subject in a more general
form.*

Resuming our account of the hill of the Camaldoli Convent,
we must notice one fact of importance. Mr Scrope remarks,
that a bed of graystone appears beneath the tufa to the
N. W. of the hill, though, from the very short abstract I have
seen of his paper,-f- the description is not very satisfactory. It
would appear, however, to be the same stratum as Breislak par-
ticularly notices in this direction under the name of Piperino. %
The want of consistent geological nomenclature, especially in
what relates to the volcanic forniations, is found to be a great
drawback in every inquiry ; but by a combination of the two
descriptions, we may arrive at some pretty distinct conclusions
on the subject before us. Mr Scrope elsewhere states, § that
graystone, according to him> is equivalent to the trachytes of
most authors ; and from this gentleman's intimate acquain-
tance with the most characteristic trachytes of the extinct vol-
canos of Auvergne, we may feel confidence in his designation
of this rock wherever he meets with it. We therefore con-
sider it as a rough porphyritic rock, composed almost entirely
of felspar, and once in a state of fusion. Mr Scrope particu-
larly mentions, as occurring in the bed beneath the tufa of
the Camaldoli, " a singular concretionary separation of the
augitic from the felspathose parts, the former appearing as
lenticular patches in a base consisting of the latter."" Breislak
describes the base of the rock as whitish, and containing crys-
tals of mica and specular iron ; and he draws some curious in-
ferences from the form of the cavities interspersed through it,
which he says contain basaltic crystals, sometimes resembling
pitch-stone, which undoubtedly correspond to the concretion-
ary augite of Scrope. The shape of the cavities he describes

• I have not here touched on the more general and abstract facts, which
lead us to the conclusion, that the sea had'formerly a higher level, the marlcs
it has left on the rocks of Capri, and this limestone coast of Italy, and the
occurrence of shells in the tufas.

j Phil Mag. New Series, i. 388.

X Campanie, torn. ii. p. 41, &c.

§ See Memoir on the Ponza Isles, Geol. Trans. New Series, vol. ii.

No. III. — Pausilipo and the Lago cCAgnano. 255

as lenticular, having the greater axes all parallel, and coin-
ciding with the direction in which the current, when fluid, (of
which he entertains no doubt,) must have progressed. Dr
Thompson considered this trachyte (if we may so call it) in-
termediate between true lavas and the tufaceous formations ;
for it must be distinguished, as Breislak remarks, from the
piperino of Rome and Albano, its name being nearly alike ;
but these being merely species of tufa exhibiting no marks of
fusion like the mass before us. Its situation, too, I consider
very interesting, since, as it is overlaid by the ordinary tufa of
Pausilipo, it must either have had a prior existence to that
substance, and appeared while the waters of the ocean retain-
ed their higher relative level, or it must have been subse-
quently elevated from below, like our trap rocks, which in
some points of view must be considered as the most probable
hypothesis, since Mr Scrope has failed in detecting any pecuo
liar geognostical position in trachyte, in a neighbouring dis-
trict to that we are now considering. *

Let us now descend from the elevated ridge to the basin in
which Lake Agnano is contained at the foot of the steep
southern descent of the hill of the Camaldoli ; and we must
here introduce a remark or two upon the origin and history
of this curious lake. After consulting all the authorities of
which I am possessed on this subject, and attentively con-
sidering the state of the localities as I myself observed them,
I feel unable to come to any decisive opinion on the sub-
ject. Certain it is that this lake is never mentioned by clas-
sic authors, and is first noticed by some writers of the middle
ages, under the name of Lacus Anclanus, supposed to have
been so called from a town named Angulanum, which is
thought to have stood on its banks, and which some still
absurdly maintain is to be seen in ruins under water, -[- a
fable not uncommon in its nature, and which, I believe, is en-
tirely refuted. The question which remains to be solved is,
why this lake, if it existed in the time of the Romans, is ne-
ver mentioned by their authors, in a region, the other features

" Geological Transadions, — uhi. sup.

"I" Ferrari, Guida di Napoli, and Breislak, ii. 48.

Z56 Mr Forbes's Physical Notices of the Bay of Naples.

of which we are so well acquainted with through their writ*
ings ; and if it did not then exist, what was its origin ? The
explanations which have been given may be reduced to two
classes ; that the Lake Agnano was nothing else anciently than
the fish-pond of Lucullus, or that it was formed by a volcanic
subsidence in the middle ages. The former opinion is not with-
out plausibility, and is strongly upheld by Eustace. * Clu-
verius seems also disposed to it. It is universally believed
that Lucullus had a villa on this spot, and ruins are shown on
the banks of the Lake, which may very probably have form-
ed part of it. We are told by Pliny that the ponds cost
more than the villa itself, which gives us a surprising idea of
their magnitude ; and we are likewise told that there was a
communication between them and the sea. An artificial cut
through a portion of the hills which bound the Lake I have
certainly observed, and considered it in this view ; but as
things stand at present, it seems unlikely that a low enough
level can exist for that purpose, but it is by no means impos-
sible, and would be worth a trial. I had intended to have
made one, but the accident which occurred to the barometer
which I destined for the measurement of Vesuvius disap-
pointed me. Others with Breislak suppose that the Lake of
Agnano owes its existence to volcanic action in the middle
ages ; and, as the former opinion derives most weight from his-
torical evidence, so does the present one from its physical con-
stitution, and I am disposed to think that the latter testimony
predominates. All writers seem to agree, that the hollow in
which the Lake of Agnano is situated displays the features of
a true, though much degraded, volcanic crater, and forms one
of a class of objects quite peculiar, of which we have undoubt-
ed examples in Lake Avernus, and the Lakes of Albano and
Nemi. I have ascertained, too, by examination, that there is
neither introduction or emission of water by streams in the
example before us, which is a frequent character of volcanic
lakes, and furnishes a presumption that Lucullus could not
have employed as a fish-pond a basin in which there is no free
current, and which sometimes approaches to stagnation, for

• Italy J iii. 430- Legliorn Edit.

No. III. — PausiUpo and the Logo cTJgnano. 257

we cannot suppose that his only pond would be that of sea
water; and it may pretty safely be affirmed, that no spring of
pure water occurs on the banks of this lake.

But here the difficulty arises, why does this lake appear not
to have existed under the Romans ? Some historical and Chris-
tian writers of the period of the decline of the empire allude to
the district of the Lucullan Villa, and the tower which was
employed as a fortification, and retained his name; but we have
not a word of the lake, which would probably have been the
case, if it had been the fish-pond then fallen into a state of
nature. The first mention of Anclanum was in the time of
the Normans, and Mazzochi assigns the 9th century as the
period of its formation ; but it seems more natural, if we are
to fix upon a hypothetical date, to suppose with Breislak that
the eruption of the Solfatara which took place in 1198, and
desolated the country round by earthquakes, shook the foun-
dations of -the valley, and made the water collect in its bottom.
The appearances of the country round well correspond with the
idea of volcanic action at no great depth, when we recollect that
the' Grotto Del Cane, the vapour baths of San Germano, and
the hot spring of La Pisciarella occur on its banks. Agnano
as it exists at present is a very agreeable spot, the hills around
which in some places rise abruptly from the shore being cover-
ed with copsewood. The water of the lake is dark-coloured,
but not stagnant, though, with that thoughtlessness of conse-
quences which so much characterizes the inhabitants of this
favoured climate, the practice of steeping flax was formerly
carried on here to such an extent in the hot season, as to ren-
der the air absolutely pestilential, and compel government to
put a stop to the practice.

In one of my visits to Agnano, (December 7th, 1826,) my at-
tention was forcibly directed to the peculiar colour of the water
of the lake near its edges. A crimson matter dyed it in zones,
parallel I think to the direction of the banks, and part of it
was thrown up upon the reeds near the Grotto Del Cane. On
examination, it had the appearance of an immense collection
of minute organic bodies, all of this uniform crimson colour.
I have reason to believe that this appearance continued at least
till March 1827. On my return from the Continent, I observ-

VOL. X. NO. II. APRIL 1829. »

258 Mr Forbes's Physical Notices of the Bay of Naples.

ed in the number of this Journal for April 1827, an inter-
esting account of a similar fact, observed on the Lake of Morat
in Switzerland, in 1825, by Professor Decandolle. It appears
to occur there every spring, and to last from November to
March or April, which coincides very well with my account.
It is then subject to many variations, disappearing in the night,
and during high winds. M. Decandolle found this colouring
matter to be composed of a new species of animals of the genus
Oscillatoria, and imputes their origin to the decomposition of
organic matter in its sluggish waters. Such an explanation will
apply equally to the Lake Agnano. These animals are de-
scribed as less than $oVo "^ ^" ^^^^ ^^ diameter, and have re-
. ceived the name of Oscillatoria ruhescens. When kept in bottles
for twenty-four hours they exhaled a fetid odour ; but the spe-
cimens I took from Agnano, though dried merely in paper,
emitted none, and even now, when macerated, have no smell what-
ever. The appearance of the matter in a dry state is compact,
homogeneous, and brittle, of a reddish brown colour. I shall
be happy to furnish anyone interested in the subject with
part of the minute quantity I possess of this substance, for the
purpose of microscopic examination.

Some authors have particularly described bubbles of air
which rise through the water of Lake Agnano. Hamilton
says this is so strong near the Grotto del Cane as to give the
appearance of ebullition, — a statement which is confirmed by
Ferrari, the Neapolitan topographer, who says it is observed
when the lake is full. Breislak denies it, and supposes the mis-
take to have risen from the motion of insects ; but there seems
no reason to doubt that so natural a phenomenon should oc-
cur, as it is nothing but aerial fluids which we know take their
rise under ground here, whether simply carbonic or sulphu-
reous, ascending through the fine felspathose and augitic sand
which composes the bottom of the Lake Agnano ; and from
the porous nature of the soil, nothing can be more easy to
imagine than that when the water assumes a higher level than
usual, a portion of it is imbibed, and gas developed. This
will explain the different relations of travellers on the subject.

At the south-east edge of the lake occurs the small emissary
of carbonic acid gas, which has so long been vaguely or inac-

No. III. — Pmisilipo and the Lago (TAgnano. 259

curately treated of, named the " Grotto del Cane ;" and the
reader need not fear that I shall trouble him with a long drawn
narration of this simple phenomenon. Ever since the de-
scription by Pliny of these " Charoneae Scorbes^' and " Spira-
cula Ditis *, travellers seem to have tried to outvie one another
in their description of the wonders of this little spot. Spallan-
zani exhausts almost as much space upon it as on Vesuvius ;
and in all the topographical works it receives its meed of ad-
miration or mystery. Professor Vairo of Naples long ago
asserted, that in the Grotto del Cane, the muscular fibres of
animals have no irritability ; that there is no electricity ; that
the loadstone draws no iron ; and that the needle is remark-
ably declining -[- ; — absurdities, to refute which, if they are
worth refutation, it is sufficient to consult the decisive experi-
ments of Breislak J. Without wasting time upon past errors,
we may collect in a few words the principal facts ascertained
regarding this grotto, and we may notice in the first place,
that it is certainly excavated from Pozzuolana,, and not out of
lava, as Ferber asserts §. It is about ten feet long and four
broad, and the height of the carbonic acid vapour at a mean,
eight Paris inches. Its temperature is considered by Breislak as
8° R. above that of the air ; but Mr Adolphus Murray found no
difference ; and I am disposed to consider the heat as accidental,
for which the great want of circulation in the cavern, and the
quantity of combustibles, burnt there by way of experiment,
will pretty well account. The composition of the mephitic va-
pour may be taken as follows : Oxygen 10 per cent, j car-
bonic acid 40 per cent. ; azote 50 per cent. It appears to
contain no sulphureous matter.

The editor of the French edition of Sir William Hamilton's
works II, who has subjoined numerous notes, justly remarks,
that one of the most surprising phenomena of the Grotto del
Cane is the continuance of its exhalations during so many

• II. 93.

T Ferber 's Travels, 177.

t Campanie, ii. 56 ; and in Spallanzani's Travels, i. 108.

§ P. 177. This author lays particular weight on this point, in which,
from the testimony of Breislak and my own observation, I am convinced
he is mistaken.

II The Abbe Giraud-Soulavie. Svo- Paris, 1781.

260 Mr Forbes's Physical Notices of the Bay of Naples.

ages, since not merely have Pliny and Seneca recounted the
general phenomena, but Tiberius actually killed two slaves by
the vapour, — an example which, if we may believe report, has
been repeated in more modern times *. The explanation offer-
ed by Spallanzani seems satisfactory, that since the basis of
this whole volcanic region is undoubtedly the Apennine lime-
stone, and as we have abundant proof of the present action of
heat in the immediate vicinity manifested by hot springs and
sulphureous exhalations, the inference is obvious, that the car-
bonic acid is disengaged from the limestone, and rises through
the cracks of the strata ; and if we are inclined to admit
that the descriptions of the ancients are too lofty for the pre-
sent condition of the vapour, we may easily see how the quan-
tity emitted may be gradually on the decline.

This opinion regarding the origin of the foul air, or Mofetta^
as it is called in Italy, is strengthened by the consideration
that the Grotto del Cane, though themost remarkable example
in this neighbourhood, it is by no means a solitary one. Ha-
milton-f* gives us several examples, particularly of mofette ap-
pearing in spots where they had not been before known. In
the excavations of Pompeii they are very abundant. I recol-
lect one underground drain near the temple of Isis being
pointed out to me as aboundirfg with them. Similar exhala-
tions occur at Naples and at Mount Vesuvius, the latter con-
taining some sulphuric acid, and most baneful to vegetable as
well as animal life. Those who interest themselves in the in-
fluence of gases upon the vegetable physiology would do well
to notice the relations of Breislak regarding the Vesuvian mo-
fette, which, though they are perhaps of a nature to excite
incredulity, seem to be warranted by the observations and ex-
periments of that able naturalist. He remarks, that " it is a
very extraordinary phenomenon that this mephitic vapour,
which destroys all vegetation, and kills in a few days trees and
•shrubs from the root, has no bad effect either upon olive or
pear trees. It is a fact confirmed by all the cultivators of the
district, and which I have sometimes verified by seeing these

• See Jorio, Pozzuoli e Contorui, 183.
t Campt Fhlegrcniy fol. Naples, i. 88.

No. III. — Pausilipo and the Lago d'Agnano. 261

two kinds of trees green and in full vigour in the midst of the
general destruction of all other plants."*

It is to exhalations such as these, and there seem to be
many more dangerous than that of the Grotto del Cane, as
those which occur at Sinuessa, that we must ascribe several of
the facts mentioned by the ancients, such as those Tartarean
waters, —

" Quam super baud ullae poterant impune volantes,
** Tendere iter pennis ;" '

expressions which apply to Lake Avernus, whose very name,
derived from the Greek 'Ao^vo?, seems to indicate the reality of
the statement ; but of this we shall have occasion to speak at
a future period. It has been asserted that water-fowl are
rarely to be seen on Lake Agnano. This, however, is a mistake.
For the theory of the evolution of mephitic vapours I may re-
fer the reader to Daubeny's work on Volcanos, p. 371 — 378.

When we advance from this lake towards the base of the
Solfatara, we enter a retired glen, and, soon after passing a
solitary cottage, reach a muddy rivulet, rolling in a bed full of
boulders in soft volcanic strata. This is the water of La Pis-
ciarella ; and, by ascending a little way, we reach the hot spring
itself, which is now covered with a small hut. Since I last
published some remarks on this spring,-|- I have collected the
observations of authors upon its temperature, which prove it
to be liable to remarkable alternations. Hamilton J declares
that he saw the thermometer in the spring rise to the boiling
point, though he admits that after rain he found it much

* Campanie, i. 221. Daubeny (Description of Volcanos, 170,) tells us,
that be has been assured that this paradoxical statement is not without
foundation. An interesting paper on the influence of gases on plants, by
Drs Turner and Christison, was published in this Journal, (vol. viii. 140 ;)
but the ingenious authors have not alluded to the influence of natural ex-
halations. Sulphurous and muriatic acid gases, however, which they chiefly
employed, are those produced by Vesuvius, and in this view the experi-
ments are very interesting. Towards the close they mention, that differ-
ent plants are very differently affected; and it would be interesting to sub-
ject the pear tree to this examination. The inquiry is well worthy of far-
ther investigation.

I See this Journal, No. xiv. p. 2Q5,

X Campi Phlegrcei, folio, i. 68.

3562 Mr Forbeis's Physical Notices of the Bay of Naples.

lower. Delia Torre* found it to be 68° R. = 185° Fahr.
From my own very careful observations, which were made in
the month of December 1826, when the temperature of the air
was 48°.5, the interior of the hut was 70°.5, and the warmest
part of the spring 11£°.5. The Abbe Giraud Soulavief stated
it so low as 1 01° Fahr. Humboldt, in his Personal Narra^
tive^X states the Pisciarelli of the Lake Agnano to have a tem-
perature of 93° Cent. = 199°.4 Fahr. At the same time there
seems to be some mistake in this part of Humboldt's work ;
for a few pages farther on, when speaking of the hot springs
of Nueva Valencia in South America, one of which has the
temperature of 90°.3 Cent. = 194.5 Fahr. he considers it the
warmest in the world, except that of Urijno in Japan, said to
be pure water at 100° Cent. Humboldt seems to be too gene-
ral in this assertion, not only in the example he himself gives
of the Pisciarella, but Dr Webster || has found the tempera-
ture of several springs in St Michael's, one of the Azores, to
be 207°, 203°, and 200° respectively. The Pisciarella, how-
ever, probably never attains now the temperature at which Ha-
milton and others observed it. Breislak§ notices some changes
which it seems to have experienced towards the close of the
last century, apparently by the falling in of the soil, which may
have materially affected it. It would appear, however, to have
been always very sensible to the effects of the weather, and par-
ticularly to the percolation of rain water.

The water of this spring contains sulphate of alumina, some
uncombined sulphuric acid, a little sulphur, and sulphate of
iron in great abundance. So predominant is the last salt, that,
if the water be mixed with galls, it immediately becomes black,
and by evaporation forms very tolerable writing ink, as I
proved experimentally. The origin of these ingredients is
easily pointed out. The alumina and vitriol it derives from
the decomposed volcanic strata of the hill from which it issues,
appropriately named Monte Secco ; and the abundant streams
of sulphuretted hydrogen gas which rise through the water,
and give it the appearance of ebuUition, by uniting with the

• Storia del Vesuvio, 4to, Napoli.

+ In his notes to the French edition of Hamilton's works, 8vo, p. 445.
+ Vol. iv. p. 171. II Edtn. Phil. Joum. vi. 308. § Campanie, ii. 66.

No. III. — PausUipo and the Lago (TAgnano. 263

oxygen of the atmosphere, form water on the one hand, and
deposit part of the sulphur, and, on the other, sulphuric acid
is produced; or rather, according to Daubeny, hypo-sulphur-
ous acid. Monte Secco forms the eastern boundary of the
hill of the Solfatara, and will therefore come to be considered
as to structure in a more general manner afterwards. - 1 may
mention, however, that its basis seems to be principally decom-
posed lava, which assumes a white and plastic condition, being
a union of felspar and silex in a minute state of division. The
vapours of the Pisciarella seem to cause the most compact
lavas to exfoliate with great ease, the constituents of which,
suspended in the water, are deposited, according to Breislak,
in beds of clay and siliceous sinter. The range of hills of
which Monte Secco forms a member, seem to have been named
by the ancients Colles Leucogaei; and Pliny* mentions waters
good for the eyes, as existing between Puteoli and Neapolis,
under the title of Fontes Leucogaei, which some have imagined
were identical with the Pisciarella ; but Breislak shrewdly re-
marks, that, from the component parts of this , spring, we
should not be tempted to consider it a very salutary lotion for
the eyes.-[-

We shall now shortly notice the last conspicuous feature of
the interesting circuit to which this paper limits us. The val-
ley, or rather basin of Astroni, lies to the north of the Lake Ag-
nano, and between the hills of the Solfatara and the Camal-
doli. It is one of the best marked- extinct volcanic craters
in existence, and besides, one of the most agreeable spots
\ ' in the whole range of the Bay of Naples. It is a hollow in a
truncated cone like a regular volcano, and its size has been
variously estimated, apparently from the small attention
which this delightful spot has excited, so that probably
few of the visitors at Naples have ever approached it, as the
guide-books rai'ely mention it, or leave it out altogether.

• Nat. Hist. lib. xxxi. 2.

t The fountains mentioned by Pliny were probably similar to those
which rose in the academic villa of Cicero, and which have b^en recorded
in verse by his freedman Tullius: —

Hinc etiam apparent lymphae non ante reperta^,
Languida quae infuso lumine rorc levant.

264 Mr Forbes's Physical Notices of the Bay of Naples.

Its circumference has been estimated at 2^ *, 3 f , 4J J, and 6
miles §. We shall not probably go far wrong if we consider
the road made round the bottom 2J miles, and the circumfe-
rence at top 4. Its depth is very considerable, and the sides
precipitous, and even overhanging. Part of the edge of the
crater is cut down to facilitate the descent at one place, which
is still very steep. It affords an interesting section represented
by Hamilton, Plate xix. This spot must once have been
the seat of continued volcanic fires at a period subsequent to
the formation of the tufaceous hills below, and, I have little
doubt, subsequent also to the retirement of the waters of the sea.
This seems demonstrated by the absence of the degrading ef-
fects of water ; and Astroni is happily placed among the sur-
rounding eminences, to exhibit the two conditions of ancient
and immemorially extinct volcanos. I give it merely as a
hint, not being qualified to speak from experience on the com-
parison, that perhaps Astroni has a geological antiquity resem-
bling that of the extinct volcanos of the Vivarais, beyond the
memory of man, but similar in constitution to craters which
have suffered recorded paroxysms, such as the Solfatara in
1198.

In conformation, this crater exhibits not merely tufa and
pumiceous conglomerates, but beds of real lava. Breislak
seems to say, that obsidian is to be reckoned among the pro-
duction^of Astroni || ; but I did not meet with any, and it is
not usually mentioned. " He also particularly notices a beau-
tiful siliceous incrustation, which, from his description, must,
I think, be fiorite. Both this substance and obsidian occur in
the Island of Ischia. As we have already noticed that the
walls of the crater are precipitous, so the bottom is flat and
extensive, upon which rise several parasitic cones, as Scrope
terms them ^, three of which ate transformed into lakes. The
distinctness of these phenomena are sufficient to prove the later
date of this volcanic crater. It has been asserted that there
are mineral springs here which supply the lakes, particularly

• Eustace. t Breislak and Daubeny. t Starke- § Hamilton.
II " L'interieure de ce cratere abonde en verresnoirs, qu'un principe de
decomposition rend ties fTagihs."'—Campanie^ ii. 64>.
% See his Considerations on Volcanos, p. 165.

No. III. — Pausilipo arid the Lago d'Agnano. ^ZQ5

by Carletti, a modern Italian writer on this region, who so
late as 1787 gave a marvellous account of their contents ; but
this would appear to be an absolute fiction.

In its present condition, Astroni is a richly wooded hollow,
or (to use the only word which can express its form) crater,
which, particularly in winter when I visited it, from the abun-
dance of evergreens which clothe its precipices and chasms,
exhibits a scene of the most romantic seclusion. Its summit
is surrounded by a wall, which is rendered hardly necessary,
from the barrier with which nature has furnished it ; and it
forms a delightful royal hunting park. Strangers are most li-
berally admitted; and none should neglect the opportunity of
enjoying a tranquillity so unique within two or three miles of
such a city as Naples. Its thickets are abundantly stocked
with wild boar, — a noble animal of its kind, — which is extremely
active, and shuns the approach of man. They generally f^ed
in herds, and are the favourite objects of the royal chace in this
part of Italy. A single hunting cottage does not interrupt
the repose of this sequestered region ; and the painter might
find many delightful subjects for his pencil, in the combina-
tion of the fine foliage of majestic trees, the craggy eminences
of the rudely piled lava, and the little lakes already mentioned,
which serve to diversify the scene. It is interesting to reflect
that the delightful scenery of Astroni was once realized in the
now desolate crater of Vesuvius. Previous to 1631, for a con-
siderable period of years, that great chasm was wooded like
Astroni, and like it was stocked with wild boar, and had its
miniature lakes.* It is impossible to divine whether the qui-
escent spot now before us may not again be disembowelled by
volcanic ravages after a longer repose, but in a condition simi-
lar to the crater of Vesuvius.

We have now surveyed in sufficient detail the region which
we proposed for our present consideration, and have made the
circuit of several ranges of hills, which are of great interest in
their constitution to the physical observer, and lead him, as I
have already observed, with great ease to several remarkable
conclusions. Some of these we endeavoured to draw, as con-
nected with the theory and origin of volcanos ; and when we

See No. I. of these Notices in this Journal, October 1828, p. 194.

266 Mr Forbes's Physical Notices of the Bay of Naples.

have completed the view of the Bay of Naples, some more ge-
neral consequences will probably present themselves. To pro-
ceed analytically from phenomena to hypotheses, and from the
present to the past or future, should be the endeavour of the
observer of nature ; and before we can hope to account sa-
tisfactorily for the appearances of extinct volcanic agency,
which we have now been describing, we must deduce a foun-
dation of facts from craters in a state of present activity. It
would be unnecessary, therefore, to speculate farther upon the
origin of the tufaceous hills of the Campi Phlegraei, till we are
prepared to take a more extensive view of the subject.

The substance named Pozzuolana I have not here touched
upon, because, though some have imagined it to form the basis
of the common tufas of Naples, in its more useful form it is
best seen in the Bay of Pozzuoli, from which it took its name,
both ancient and modern *. We shall therefore speak of it
when we come to consider that quarter.

The district we have described is not less interestinor, from
its picturesque or gently beautiful features, than for its physi-
cal importance. Imaginative as well as natural beauties com-
bine to enhance the scene, and Parthenope, while she enjoys
the lustre of classical and poetic associations, is surrounded by
the lavish profusion of nature'*s most attractive charms ;
" Earth, sea, and sky, the brightest in the world !"

We cannot doubt that the Italian poets, modern as well as
ancient, have embellished their descriptions with scenes taken
from the Phlegraean fields ; and Tasso in particular, who was
a native of this part of Italy, seems to have had in his view,
when describing the enchanted gardens of Armida, scenes like
those of Pausilipo or Astroni.

" Acque stagnanti, mobili cristalli
Fior vari e varie piante, erbe diverse
Apriche coUinette, ombrose valli
Selve e spelunche, in una vista ofFerse."

Ger. Lib. xvi. 9.

• It is the Pulvis Fvieolanus of Vitruvius.

Meteorological Register for 1822, S^c. 267

AiiT. XI. — Abstract of the Meteorological Register for 1822,
1823, 1824, and 1825, from Observations made by the Svat-
geons of the Army at the Military Posts of the United States
Army. Prepared under the direction of Joseph Lovell,
M. D. Surgeon-General of the United States Army.

It is with a satisfaction of a very pecuUar kind that we ob-
serve the great exertions made in the cause of science, not only
by the general government of the United States, but even by
the local governments of that extensive and interesting country.
We have already seen (see this Journal, vol. viii. No. xvi.
p. 303,) that the legislature of the State of New York has en-
joined the Regents of the different Universities within their
bounds to make annual returns of the state of the thermome-
ter, rain-guage, and weather, and that the first report has been
given to the public. Long before this, in 1821, Mr Calhoun,
Secretary of 3tate for the War Department, had suggested
and ordered to be carried into effect a regular series of meteo-
rological observations to be made by the surgeons of the
United States army. This great work, which will immortalize
the name of Mr Calhoun, has been carried into effect for four
complete years; and, as no account of the register has been pub-
lished in any of our scientific journals, we trust our readers
will be gratified with the following abstract of it. We are
enabled to do this through the kindness of Captain Basil Hall,
who has been so good as to put into our hands a copy of the
printed report.

" On the question whether in a series of years there be any
material change in the climate of a given district of country ;
and if so, how far it depends upon cultivation of the soil, den-
sity of population, &c. the most contradictory opinions have
been advanced. While one contends, that, as population in-
creases and cultivation extends, the climate becomes warmer,
another is equally convinced that it becomes colder, and a
third, that there is no change in this respect. These opinions
are for the most part founded on a comparison of the climate
of Europe at the present day with what it is supposed to have
been two thousand years ago ; and their great discrepancy may

268 Meteorological Register for 1823-4-5, kept at the

in some measure be accounted for from the circumstance, that
the facts are few and the period of observation remote ; while
the changes, if any, have been exceedingly slow, and their ratio
to the alleged causes exceedingly uncertain.

" The United States, however, appear to offer an opportu-
nity of bringing the question to the test of experiment and ob-
servation. For here within the memory of many now living,
the face of whole districts of country has been entirely chang-
ed ; and in several of the States two centuries have effected
as much as two thousand years in many parts of Europe. In
this respect, the ' Landing of the Pilgrims' in 1620 is as re-
mote a period as that of the' invasion of Gaul or of Britain by
Julius Caesar.

" The time for improving this opportunity, however, like
that for recording the history, language, manners, and customs
of the aborigines of the country, is fast passing away ; and in a
few generations, both these sons of the forest and the intermi-
nable wilderness they inhabited will, for all useful purposes,
be as though they had never been. As, therefore, the military
posts within the United States afford every convenience for
making numerous observations over an extensive district of
country, and regular diaries of the weather have for some
years past been kept at most of them, the following tables have
been prepared in the form that appears best calculated for re-
ference, in order to preserve the facts thus collected.

" The first twelve tables for each year give the mean of the
observations at the several posts for each month, and the thir-
teenth the mean for the whole year. The last, or general
table, gives the average of all the observations at the several
stations, and also the average for the several years, calculated
in the manner hereafter stated. Should it be practicable to
obtain similar observations for eight or ten years, it is proposed
to collect, if possible, such as may have been made at an early
period after the settlement of the country, in order to ascertain
what changes, if any, have taken place, either in the mean
temperature, the range of the thermometer, the course of the
winds, or the weather in the Atlantic States.

" The posts at which these observations were made are situ-
ated between 9.T bT and 46^39' of north latitude, and be-

Military Posts of the United States. 269

tween 67° 04' and 95° 43' of lontritude west from Greenwich ;
embracing an extent of 18° 42' of latitude, and 28° 39' of longi-
tude. The elevation of the north-western or interior stations
above those on the Atlantic coast has not been accurately as-
certained. The following, however, is believed to be near the
truth. Fort Brady, situated at the outlet of Lake Superior,
is 595 feet above the level of tide water ; Fort Howard, at the
southern extremity of Green Bay, which empties into Lake
Michigan, 600 feet ; Fort Crawford, at Praire du Chien, near
the junction of the Wisconsan and Mississippi rivers, 580 feet ;
Fort Snelling, near the junction of the St Peters and Missis-
sippi rivers, 780 feet ; Council Bluffs, a few miles above the
junction of the Platte and Missouri rivers, 800 feet. Baton
Rouge, on the Mississippi, 120 miles above New Orleans, and
Cantonment Jesup, near the Sabine river, 25 miles from Natch-
itoches, are in Louisiana ; Cantonment Clinch, near Pensaco-
la. Cantonment Brooke, near Tampa Bay, and St Augustine,
in Florida. Fort Moultrie is in the harbour of Charleston,
South Carolina ; Fort Johnston near Smithville, North Caro-
lina ; Fort Severn at Annapolis in Maryland ; Fort Mifflin in
the Delaware, 6 miles below Philadelphia ; Fort Columbus in
the harbour of New York ; Fort Wolcott in the harbour of
Newport ; and Fort Sullivan near Eastport, in the State of
Maine. The observations at the city of Washington are in-
troduced by way of comparison, as the latitude of this city is
very nearly the same with that of the centre of the several
miUtary posts. They were made by the Rev. Mr Little, by
whom they were very politely furnished for the present pur-
pose.

" Although, from the circumstances under which these ob-
servations were made at several of the posts, they may not be
as accurate as could be wished, yet they are perhaps suffici-
ently so for the purpose of general abstracts ; for the mean of
each month being deduced from 90, and of each year from
1095 observations, occasional errors would not materially af-
fect the general result.

" The chief object at present being to record facts, the fol-
lowing remarks are premised merely for the convenience of
those who may be curious in these jnatters without wishing

270 Meteorological Reguterfor 1823-^5, Jcept at the

the trouble of tedious calculations. In order to ascertdn the
means for the several years, as given in the last table, the ex-
treme stations are taken, and as many intermediate ones, at the
north and south respectively, as are found to be equi-distant
from them, or nearly so. Thus in 1822, Fort Snelling is the
extreme northern, and Cantonment Clinch the extreme south-
ern post; Council Bluffs is 3° 28' south of the former, and
Fort Johnston 3° 36'' north of the latter, &c. The aggregate
of these should give the mean of the centre of the district of
country in which the observations were made ; and the result
appears to be near the truth. For the latitude of the city of
Washington is 38° 53^, and the average mean temperature is
56.56 ; the centre of the several stations at which these obser-
vations were made is in latitude 38° 13', and the average mean
temperature is 56.52. In comparing the eastern and western
posts, those in about the same latitude are of course taken ;
thus. Council Bluffs is 24° 25' west, and but 0°05' north of
Fort Wolcott ; Fort Snelling is 26° 04' west, and but 0° 09'
north of Fort Sullivan. To prevent the constant repetition
of the terms east and west, the numbers only are stated ; it
being always understood that the first relates to the east and
the second to the west; thus, in January 1822 the means are
stated to be 22.20 and 16.25, that is, 22.20 at the east, and
16.25 at the west.

" In 1822 the aggregate mean temperature of the year was
57.06; the highest degree 108; the lowest — 29; and the range
1S7. The proportion of winds was N. 5.07, S. W. 4.95,
N. W. 4.93, S. 4.60, S. E. 3.39, W. 3.10, N. E. 2.67, E.
1.71. The proportion of weather, fair 18.90, cloudy 5.0S,
rain 5.63, snow 0.85. At Fort Snelling, the most northern
station, the mean for the year was 44.32 ; the highest degree
92, the lowest — 29, and the range 121. At Cantonment
Clinch, the most southern station, the mean for the year was
68.97, the highest degree 93, the lowest 20, and the range 73.
On comparing the eastern and western posts, it appears that at
the former the mean temperature of the winter months is much
higher, and that of the summer months much lower than at
the latter. Thus in January it is 22.20 and 16.35, February
27.40 and 26.40, March 35.52 and 41.10, April 42.31 and

Military Posts of the United States. ^1

46.53, May 55.21 and 62.60, June 6^6^ and 72.10, July
68.33 and 77.54, Auo-ust 66.52 and 75.02, September 6^.54^
and 64.19, October 51.25 and 45.84, November 42.29 and
32.96, December 29.55 and 80.03. During the six winter
months the means are 34.73 and 28.44; being 6.26 higher at
the east, and during the summer months they are 69.76 and
66.33 ; being 6.67 lower at the east than at the west ; making
but a fractional difference for the year, which was 47.24 at the
east, and 47.38 at the west. The highest degrees were 88 and
108, the lowest — 9 and — 29, the ranges 97 and 137 ; and it
was greatest at the west, not only for the year, but also for
every month except July and August, when it was about the
same. The course of the winds was N. 3.54 and 5.08, N. W.
6.29 and 7.25, N. E. 1.91 and 3.08, E. 1,21 and 0.96, S. E.
17.9 and 3.63, S. 504 and 304, S. W. 7.37 and 5.37, W. 3.26
and 1.96. Weather, fair 18.34 and 19.75, cloudy 7.37 and
4.17, raih 4.00 and 4.33, snow 0.34 and 2.16. Prevailing
winds at the east, S. W. N. W. and S. at the west, N. W.
S. W. and N. The proportion of fair weather and rain was
nearly equal ; of cloudy weather much more ; and of snow
much less, at the east.

" In 1823 the aggregate mean temperature of the year was
55.22; the highest degree 100; the lowest — 38; and the
range 138. The proportion of winds was S. W. 7.22, N. E.
4.84, S.E. 4.10, N.W. 3.85, S. 3.19, N. 3.15, W. 2.29,
E. 1.65. Weather, fair 16.48, cloudy 6.16, rain 5.98,
snow 1.77. At Fort Brady, the most northern post, the
mean of the year was 39.66 ; the highest degree 90 ; the low-
est — 30 ; and the range 120. At Cantonment Clinch, the most
southern station, the mean was 68.25 ; the highest degree 94 ;
the lowest 11 ; and the range 83. On comparing the eastern
with the western posts, the mean of the winter months for this
year also is higher, and of the summer months lower, at the
east. Thus in January it is 24. 12 and 21 .05, February 21.90
and 15.62, March 32.65 and 32.42, April 42.41 and 48.82,
May 51.19 and 57.02, June 64.60 and 72.50, July 66.76 and
75.36, August 66,65 and 72.89, September 58.79 and 60.14,
October 49.92 and 49.12, November 35.79 and 35.67, De-
cember 32.05 and g3.77. During the winter months the

272 Meteorological Register for 1823-4-5, kept at the

means are 32.73 and 29.61, being 3.12 higher at the east ; and
during the summer months 58.40 and 64.45, being 6.05 lozaer
at the east. The means for the year are 45.50 and 47.03,
being 1 .53 higher at the west, where the winter was compa-
ratively warmer than in 1822. The highest degrees were 90
and 102, the lowest — 10 and — 30 ; the ranges 100 and 132.
Course of the winds, N. 3 and 2.03, N. W. 7.50 and 2.79,
N. E. 2.83 and 6.87, E. 1.24 and 1.87, S.E. 1.83 and 2.23,
S. 5.08 and 3.20, S. W. 5.95 and 9.50, W. 2.95 and 1.83.
Weather, fair 15.12 and 18.41, cloudy 9.62 and 7.95, rain
4.16 and 2.40, snow 1.50 and 1.58. Prevailing winds at the
East N. W., S. W. and S. ; at the West S. W., N. E. and S.
The proportion of fair weather was considerably less, of
cloudy weather and rain considerably greater, at the east ;
the proportion of snow about the same.

In 1824 the aggregate mean temperature of the year was
55.56 ; the highest degree 96; lowest — 33 ; and the range 129.
The proportion of winds, S. 5.33, S. W. 4.73, N. W. 4.65,
N. 3.85, S. E. 3.83, W. 3.40, N. E. 2.84, E. 1.79. The pro-
portion of weather, fair 17.55, cloudy 5.03, rain 6.29, snow
1 .49. At Fort Brady, the most northern post, the mean tem-
perature was 40.94 ; the highest degree 89, the lowest — 33 ;
and the range 122. At Cantonment Clinch, the most south-
ern station, the ihean temperature was 69.10, highest degree
95, lowest 24, range 71. On comparing the eastern and west-
ern posts, the means for January were 27-22 and 25.82, Fe-
bruary 26.62 and 22.70, March 33.45 and 28.45, April 44.12,
and 44,78, May 50.61 and 58.43, June 60.77 and 66.28,
July 67.49 and 74.49, August 65.61 and 71.53, September
60.44 and 62.00, October 49-96 and 46.91, November 38.50
and 30.28, December 32.41 and 26.53. During the winter
months the means were 34.69 and 30.11, being 4.58 higher
at the east; and during the summer months 58.17 and 6292,
being 4.75 lower at the east. The means for the year 46.43
and 46.51, a difference of but 0.08. The highest degrees
were 86 and 103, the lowest — 19 and — "21, the range 105 and
124. Course of the winds, N. 3.16 and 4.45, N. W. 6.83 and
1.20, N. E. 2.58 and 6.70, E. 1.50 and 1.00, S.E. 1.70 and
187, S. 4.28 and 6.78, S. W. 6.33 and 8.12, W. 3.45 and 0.36.

Military Posts of the United States. 273

Weather, fair 16.58 and 18.04, cloudy 8.50 and 7.04, rain
4.70 and 3.33, snow 0.70 and 2.08. The prevailing winds at
the east were N. W., S. W. and S. ; at the West S. W., S.
and N. E. The proportion of fair weather was less, and of
cloudy weather and rain greater, at the east, the proportion of
snow much less.

" In 1825 the aggregate mean temperature of the year was
58.27 ; the highest degree 102; the lowest — 25 ; and the range
127. The proportion of winds, S. E. 5.52, N. W. 4,81, N.E.
4.72, W. 3.24, N. 3.23, S. W. 3.09, S. 2.79, E. 1.45. The
proportion of weather, fair 16.91, cloudy 5.67, rain 6.49,
snow 1.32. At Fort Brady, the most northern station, the
mean for the year was 40.60 ; highest degree 89 ; lowest — 25 ;
range 114. At Cantonment Brooke, the most southern sta-
tion, the mean for the year was 72.37 ; the highest degree 92 ;
the lowest 40 ; range 52. On comparing the eastern and west-
ern posts, the means in January were 26.34 and 1 7.63, Febru-
ary 27.67 and 29.58, March 36.89 and 38.31, April 45.12
and 57.32, May 53.37 and 63.94, June 65.04 and 71.86, July
70.98 and 75.42, August 68.12 and 74.83, September 59-86
and 63.60, October 51.94 and 50.36, November 41.1S and
38.50, December 31.65 and 19.26. During the six winter
months the means were 35.94 and 32.27, being 3.67 higher at
the east ; and during the summer months 60.41 and 67.83,
being 7.42 lower at the east. The means for the year were
48.17 and 50.05, being 1.88 warmer at the west ; the highest
degrees were 94? and 102, the lowest — 5 and — 25, the ranges
99 and 127. The course of the winds was N. 2.91 and 4.03,
N. W. 6.25 and 5.74, N. E. 3.50 and 2.16, E. 1.54 and 1.50,
S.E. 1.62 and 4.58, S. 3.62 and 5.29, S. W. 7.83 and 4.37,
W. 3.54 and 2.66. Weather, fair 16.53 and 16.25, cloudy
9.62 and Q.m, rain 3.62 and 6.12, snow 0.60 and 1.41. Pre-
vailing winds at the East S. W., N. W. and S. ; at the West
N. W., S. and S. E. The proportion of fair weather was
about the same; of cloudy considerably greater; and of rain
and snow much less, at the east.

" By the last table it appears that the aggregate mean tem-
perature was highest in 1825 and lowest in 1823, there being,
however, but a fractional difference between this and the fol-

VOL. X. NO. II. APRIL. 1829- S

274 Meteorological Register Jot' 3 8^3-4*-5, kept at the

lowing year. The average of the whole period is 56.52, being
about one degree lower than at Bourdeaux in latitude 44° 50''.
The range was greatest in 1822 and 1823, and nearly equal ;
and several degrees less in 1824 and 1825, being least in the
latter year. The N., N. W., W. and E. winds are most uni-
form in the several years ; the rest are more variable. The
prevailing winds are S. W., N. W., and S. E. The propor-
tion of fair weather was greatest in 1822, and least in 1823,
which, however, differed but little from 1825. The proportion
of cloudy weather, rain, and snow, is pretty equal, except that
there was much less snow in 1822. The aggregate mean for
the whole period was, fair 17.46, cloudy 5.47, rain 6.10,
snow 1.36.

" In 1822 the mean temperature at the east and west was
nearly equal. In 1823, 1.74 lower at the east, and but 0.33
lower at the west, than in the previous year ; the winter being
comparatively milder at the west. In 1 824, the mean tempe-
rature was again nearly the same, but about one degree lower
than in 1822. In 1825, it was higher than in any previous
year, and 1 .88 higher at the west than at the east. The ave-
rage for the four years was 46.83 and 47.74, being 0.91 high-
er at the west. In 1822 the range was 40° greater at the
west; in 1823 it was 32° greater; in 1824, 19°; and in 1825,
25°. The greatest proportion of fair weather, both at the east
and west, was in 1822 ; with rather the most at the west. In
1823 there was much less at the east, and somewhat less at
the west, than in the former year. In 1824, there was rather
more at the east, and about the same at the west as in 1823 ;
and in 1825 it was about the same at the east, and consider-
ably less at the west, than in the previous year. The propor-
tion of rain was nearly the same at the east during the four
years, but somewhat less in 1825. There was a great differ-
ence at the west, being much greater in 1825, than in any
other year, and much less in 1823. The proportion of snow
was much the greatest at the east in 1 823, and least in 1822 ;
at the west it was greatest in 1822 and 1824, and least in
1825. The average for the four years was, fair 16.64 and
18.11, cloudy 8.86 and 6.44, rain 4.12 and 4.04, snow 0.78
and 2.05 ; being rather more fair, and less cloudy weather.

Military Posts of the United States.

215

with about the same proportion of rain, and much mcilre snow,
at the west. t^^> ^^Rt

" The following table may serve to compare the annual mean
temperature at some of the military posts in the United States,
with that at several places on the other side of the Atlantic,
and shows that it is considerably greater at the latter, and
especially in the higher latitudes.

Places.

North
Latitude.

Longitude.

Mean Tempe-
rature.

Petersburg,

59" 5&

30°24' E.

38° 80

Stockholm,

59 20

18 00 E.

42 S9

Edinburgh,

55 57

3 00 W.

47 70

Berlin,

5% 32

13 31 E.

49 00

Leyden,

52 10

4 32 E.

52 25

London,
Rouen,

51 31
49 26

51 90
51 00

1 00 W.

Paris,

48 50

2 25 E.

52 00

Vienna,

48 12

16 22 E.

51 53

Nantes,

47 13

1 28 E.

55 53

Poitiers,

46 39

0 30 E.

53 80

Fort Brady,

46 39

84 43 W.

41 37

Padua,

4i 23

12 00 E.

52 20

Fort Snelling,

44 53

93 08 W.

45 00

Bourdeaux,

44 50

0 26 W.

57 60

Fort Sullivan,

44 44

67 04 W.

42 44

Fort Howard,

44 40

87 00 W.

44 50

Marseilles,

43 19

5 27 E.

61 80

Fort Crawford,

43 03

90 53 W.

45 52

Fort Wolcott,

41 30

71 18 W.

51 02

Council Bluffs,

41 25

95 43 W.

50 82

Pekin,

39 54

116 29 W.

55 50

Washington,

38 53

76 55 W.

56 5Q

Algiers,

36 49

2 17 E.

72 00

Fort Johnston,

34 00

78 05 W.

QQ 68

Cantonment Clinch,

30 24

87 14 W.

68 77

Grand Cairo,

30 00

31 23 E.

73 00

St Augustine,

29 50

81 27 W.

72 23

From this it appears that in the higher latitudes the average
difference for the same degree of mean temperature is 1 4° 30',

276 Meteorological Register for 1823-4-5, kept at the

and in the lower ones 7° SCV, the mean of which is 11°. Thus
the mean temperature at Stockholm, in latitude 59° 2(y, is
about the same as at Fort Sullivan, in latitude 44° 44' ; while
that at Rouen, in latitude 49° 26', is about the same as at
Fort Wolcott, in latitude 41° 2(y ; and at St Augustine, in la-
titude 29° 50' it is but 0.77 lower than at Grand Cairo, in la-
titude 30«."

Jos. LOVELL.

Before we proceed to give the general abstract of all the ob-
servations at the different statipns, we shall give the situation
and elevation of the places of observation, so far as they have
been determined.

N. Lat.

W. Long.

in fee

Fort Brady,

46°39^

84° 43'

595

Fort Snelling,

44 53

93 08

Fort Sullivan,

44 44

67 04

Fort Howard,

44 40

87 0

600

Fort Crawford,

43 oa

90 53

580

Fort Wolcott,

41 30

71 18

Council Bluffs,

41 25

95 43

800

Fort Columbus,

40 2

74 02

Fort Mifflin,

39 5

75 12

Fort Severn,

38 58

76 27

Washington,

38 53

76 55

Fort Johnston,

34 0

78 05

Fort Moultrie,

32 42

79 56

Cant. Jesup,

81 30

93 47

Baton Rouge,

30 26

91 18

Cant. Clinch,

SO 24

87 14

St Augustine,

29 50

81 27

Cant. Brooke,

27 57

82 35

Mean,

38° 10'

82°36'

The general results of all the meteorological observations
are given in three tables :—

The following table contains the temperature at 7'* a. m.
2** p. M., and 9^^ p. m., — the mean annual temperature, — the
maximum, — minimum and range on an average of three years.

Military Posts of the United States. 277

General Annual Results for 1823-4-5.

Thermometer.

riaces of Observation.

Mean Temperature. 1) g p.

II 1

vii. ii. ix. tc'^ *^

Fort Brady,

36.69 49.06 38.38 41.37

90 .

-S3 123

Fort Snelling,

39.96 52.34 42.70 45.00

—29 125

Fort Sullivan,

38.26 49.51 39.66 42.44

—19 113

Fort Howard,

37.81 52.98 42.71 44.50

100

—38 138

Fort Crawford,

39.06 53.92 43.58 45.52

—28 124

Fort Wolcott,

48.54 56.39 48.14 51.02

— 1 89

Council Bluffs,

44.22 60.14 48.11 50.82

108

—21 129

Fort Columbus,

48.37 59.77 50.34 52.82

104

— 3 107

Fort Mifflin,

51.68 63.31 50.85 55.28

6 90

Fort Severn,

53.40 62.11 56.70 57.40

8 84

Washington,

52.23 62.18 66M m,5Q

10 85

Fort Johnston,

63.98 69.38 66.68 66.68

26 66

Fort Moultrie,

61.93 67.81 63.75 64.49

19 73

Cant. Jesup,

61.83 74.89 68.22 68.31

7 90

Baton Rouge,

62.87 74.54 66.82 68.07

18 81

Cant. Clinch,

64.43 74.12 67.77 68.77

11 84

St. Augustine,

70.94 74.46 71.29 72.23

42 52

Cant. Brooke,

68.64 79.05 69-42 72.37

40 52

1822 52.25 6S.47 55.48 57.06 108 —29 137
Average o/r ^ggg 51^6 60.68 53.72 55.22 100 —38 138

the severGLL J

.,.nr. 1 1824 51.27 61.22 53.90 55.m 96 —33 129

years, ■

1825 54.48 63.56 56.78 58.27 102 —25 127

Average, 52.31 62.24 54.97 56.52 108 —38 146

The following table shows the state of the winds, the whole
numbers in each column being the number of days in the
month of 30 days that the wind blows from any particular
quarter.

278 Meteorological Register fw 1823-4-5, kept at the

General Anminl Results for 182^4-5.
Winds.

N. N.W. N.E. E. S.E. S. S.W. W. .-a .

Places of Observation. — > ^

Days. Days. Days. Days. Days. Days. Days. Days. £ "^

Fort Brady, 1.74 4.77 1.05 2.24 7.24 2.60 2.27 8.24 W.

Fort Snelling, 2.88 7.13 2.33 1.16 4.02 3.52 6.05 3.24 N.W-

Fort Sullivan, 3.26 6.89 2.04 2.08 0.79 7.02 3.68 4.77 S.

Fort Howard, 0.70 0.70 11.52 0.19 0.08 0.39 16.04 0.78 S.W.

Fort Crawford, 5.58 7.12 1.04 0.29 4.12 5.70 3.04 1.58 N.W.

Fort Wolcott, 3.04 6.54 3.37 0.66 2.68 2.00 10.06 1.83 S.W.

Council BlufFs, 5.89 4.52 2.12 1.83 4.02 7.39 3.06 1.60 S.

Fort Columbus, 0.72 9.02 3.49 0.87 4.04 3.91 6.29 2.06 N.W.

Fort Mifflin, 0.50 6.37 4.54 0.74 6.20 1.24 8.20 2.62 S.W.

Fort Severn, 3.08 6.00 4.00 2.00 3.33 6.91 2.16 2.33 S.

Washington, 2.62 7.47 4.97 1.05 3.19 2.66 7.63 0.74 S.W.

Fort Johnston, 8.79 3.29 1.31 1.60 0.64 8.97 1.56 4.24 S.

Fort Moultrie, 1.78 1.15 6.85 3.80 5.59 5.07 4.41 1.73 N.E.

Cant. Jesup, 2.38 2.99 4.38 3.80 7.05 3.28 4.55 1.97 S.E.

Baton Rouge, 4.58 3.00 2.50 2.67 5.00 4.84 4.75 3.08 S.E.

Cant. Clinch, 2.05 4.10 4.13 1.47 7.11 2.05 8.67 0.80 S.W.

St Augustine, 1.08 2.91 12.50 1.75 7.50 0.75 2.50 1.41 N.E.

Cant. Brooke, 0.16 4.00 7.08 3.00 4.58 2.83 6.25 2.50 N.E.

1822 5.07 4 93 2^7 1.71 3.39 4.60 4.95 3.10 N.

Average of^ 1823 3.15 3.85 4.84 1.65 4.10 3.19 7.22 2.29 S.W.

1824 3.85 4.65 2.84 1.79 3.83 5.33 4.73 3.40 S.

1825 3.23 4.81 4.72 1.45 5.52 2.79 3.09 3.24 S.E.

the several
years

Average, 3.82 4.56 3.77 1.65 4.21 3.98 5.00 3.01 S.W.

The following table shows the average state of the weather
during all the years of observation, the numbers representing
the days and decimals of a day in the months of 80 days that
were/fli^j &c.

Military Posts of the United States.

279

General Annual Results for 1823-4-5.

Weather.

Fair.

Cloudy.

Rain.

Snow.

•2

Places of Observation.

Days.

Fort Brady,

13.30

3.27

7.83

6.02

Fair.

Fort Snelling,

16.94

5.50

5.77

2.22

Fair.

Fort Sullivan,

17.91

9.39

2.31

0.81

Fair.

Fort Howard,

15.47

7.98

4.56

2.42

Fair.

Fort Crawford,

16.80

6.29

3.87

1.33

Fair.

Fort Woicott,

15.31

8.16

5.94

1.02

Fair.

Council Bluffs,

19.68

6.54

2.95

1.25

Fair.

Fort Columbus,

m41

3.56

5.47

0.98

Fair.

Fort Mifflin,

Sl.SO

5.12

5.20

0.41

Fair.

Fort Severn,

19.67

4.50

5.08

1.17

Fair.

Washington,

17.30

6.05

6.44

0.63

Fair.

Fort Johnston,

16.87

7.60

5.85

0.12

Fair.

Fort Moultrie,

22.89

2.48

5.00

0.02

Fair.

Cant. Jesup,

18.63

4.49

7.25

0.05

Fair.

Baton Rouge,

20.16

4.08

6.16

Fair.

Cant. Clinch,

18.69

2.27

9.46

Fair.

St Augustine,

20.66

S.9I

5.83

Fair.

Cant. Brooke,

18.16

3.91

8.33

Fair.

.\sm

18.90

5.03

5.63

0.85

Fair.

Average of\ 18^3

16.48

6.16

5.98

1.77

Fair.

tlie several < -i c><^a

17.55

5.03

6.29

1.49

Fair.

"'""' I 1825

16.91

5.67

6.49

1.32

Fair.

Average, 17.46 5.47 6.10 1.36 Fair.

The thermometrical observations recorded in the preceding
tables were made at three different hours of each day, namely,
7'' A. M., 2h p. M., and 9^ p. m, the hours recommended by Pro-
fessor Dewey of Williamston, in the United States, giving, by
taking their mean, the mean daily temperature throughout the
year. According to the hourly meteorological observations
made at Leith-Fort, (see this Journal^ vol. v. No. ix. p. 18,)
the mean of the hours 7, 2, and 9> selected by Professor Dewey,
is about three quarters of a degree above the true mean of the
day ; and though the observations upon which Professor Dewey
proceeded were made in America, yet, as they were not made for
a whole year, we may be allowed to place more confidence in the
Leith results ; and for this reason to conclude that all the ag-

280 Mr Threlkeld's Therrnometrical Observations

gregate mean temperatures in the preceding table should be
diminished by about fths of a degree.

By examining the preceding observations, it appears that
at all the stations the time of the evening at which the mean
temperature occurs is before 9'' p. m. and after T' a. m.

If we compute the mean temperature of a point correspond-
mg with the mean position of all the above stations by means
of Dr Brewster's General Formula for the Western Hemi-
sphere of the globe, we shall have

Mean temperature by Formula, - 54°80

Do. observed, - - 56 52

Difference, - - 1°72

The observed mean temperature ought, from what has been
above stated, to be diminished about fths of a degree ; and it
requires also to be increased, in order to reduce the mean tem-
perature of the elevated stations to the level of the sea ; but as
the elevations of several of the stations are not known, it is out
of our power to apply the requisite correction.

Art. XII. — Thermometrical Observations made at Raiatea,
one of the Society Islands^ hi 182^. By the Rev. L. E.
Threlkeld.*

The following series of very valuable observations were made
in 1822, by the Rev. L. E. Threlkeld, one of the missionaries
at Raiatea or UHetea, one of the Society Islands. It is si-
tuated in west long. 151°30/, and south latitude 16°40'.

The tide at Raiatea, which rises about two feet, is never at any
time affected by the moon, and is always highest at 12 o'clock.

Although the quantity of rain which fell in this island was
not measured, yet the number of rainy days is marked in the
Journal, and are as follows : —

January, 18 May

February, 20 June,

March, 20 July,

April, 21 August,

Number of rainy days, 222
• The Etlitoi:.has been indebted for these observations to James Dunlop, Esq.
I From the 22d till the 31st of July no account of the rainy days was kept.

September,

October,

November,

December,

made at Raiatea, one of the Society Islands. 281

The following table shows the mean temperature of the different
months of 1822, by morning, noon, and evening observations :

1822.

Morning.

Noon.

Evening.

January,

74°.7

82^.

79°.5

Febrifary,

79,2

82.6

80.2

March,

83.4

80.3

April,

77.3

82.4

78.6

May,

76.6

80.8

77.8

June,

79.3

79.6

76.3

July,

73.8

78.3

August,

75.9

80.1

77.5

September,

75.4

76.9

October,

76.1

80.2

77.5

November,

75.6

December,

76.3
Mean, 76°.6

81 .6

79.7

81°.00

77°94

Mean annual temperature for 1822 by the table, 78^51.

It is obvious, however, that, as there was no night observa-
tions to balance those made at noon, we must reject the noon
observations, in order to obtain the correct mean temperature.
We shall thus obtain, —

Mean temperature for 1822, - - 76°.77

Mean temperature calculated by Dr Brewster's

General formula, - - - 76 .11

*• Error of the formula, 0°.66

The above result gives for the temperature of the equator
80°. 14 differing only 0.3 from the measure obtained in No.
XV. p. 67.

In the 10th Number of this Journal^ p. 370, we have given
the mean temperature of Hawai, one of the Sandwich Islands,
situated nearly in the same longitude, viz. in 155^° (west
long.,) and in a parallel of latitude a little more north than
that of Raiatea is south of the equator, as ascertained by
the American Missionaries in 1822. The mean temperature
of Hawai was 75°.19j the temperature calculated by the For-
mula 74°.77, giving an error of only 0°.33. Hence we may
conclude that the formula represents very accurately the mean
temperature of that part of the globe.

282 Mr Tregaskis on the Elastic force of Vapour.

Art. XIII. — Notice on the Elastic Fcyrce of Vapour. By Ri-
chard Tregaskis, Esq. Communicated by the Author.

The freezing point being zero, call the temperature and the
force at any given distance above it — unity. Raise the tem-
perature from that point, till the force be doubled, and it will be
found that Jth only is added to the temperature. Here the
temperature is IJth; the force 2. And hence l|th, or 1.2
(not 14 reduced to 1.2, as printed on page 69 of the last Num-
ber,) is the ratio of temperature, 2 the ratio of force.

That this law continues in operation from 15 to 240 inches
of mercury, appears from the following table :- —

The force of steam at various temperatures in inches of
mercury.

By Experiment. By Calculation.

Abov6

Fahr. Inches. Freezing. ^^^^^' Inches.

^^^ JL« ^T"''°""'l 150» 182° IS

15.86 Dalton, J

212 30 Atmospheric pressure, 180 212 30

248.5 60.40 Ure, - 216 248 60

Ifa Jo^-^^ ?'':, 1 259.2 291.2 120

293 120 Southern, J

343.6 240 Southern, - 311.04 343.04 240
The experiments in Article X. of the last Number did not

appear on the same page with the calculation. This circum-
stance, which made the comparison difficult, together with an
error of the press noticed above, which rendered that part of
the article obscure, will, it is hoped, be accepted as an apo-
logy for introducing the subject again.

Art. XIV. — Descriptionqf some remarJcahle Nebulce and Clus-
ters of Stars in the Southern Hemisphere, observed at Pa-
ramatta in New South Wales.* By James Dunlop, Esq.

The following nebulae and clusters of stars in the southern
hemisphere were observed by me. at my house in Paramatta,

• This is an abstract of Mr Dunlop's large and valuable Catalogue
published in the Fhil Trans, 1828, p. 113. It is illustrated by seven
large Plates, which it is impossible to copy into a Journal.

Mr Dunlop's Catalogue qf'NebuIce, Sfc. 283

»
situated about 6" of a degree south and about 1^78 of time

east of the Brisbane Observatory. The observations were
made in the open air, with an excellent nine-feet reflecting te-
lescope, the clear aperture of the large mirror being nine
inches. This telescope was occasionally fitted up as a meri-
dian telescope, with a strong iron axis firmly attached to the
lower side of the tube nearly opposite the cell of the large mir-
ror, and the ends of the axis rested in brass Y's, which were
screwed to blocks of wood let into the ground about 18
inches, and projecting about 4 inches above the ground ; one
end of the axis carried a brass semicircle divided into half de-
grees, and read off by a vernier to minutes. The position and
index error of the instrument were ascertained by the passage
of known stars. The eye end of the telescope was raised or
lowered by a cord over a pulley attached to a strong wooden
post let into the ground about two feet : with this apparatus I
have observed a sweep of eight or ten degrees in breadth with
very little deviation of the instrument from the plane of the
meridian, and the tremor was very little even with a considera-
ble magnifying power. I made drawings or representations of
a great number of the nebulae and clusters at the time of ob-
servation, several of which are annexed to this paper ; and also
very correct? drawings of the Nebulae major and minor, to-
gether with a representation of the milky nebulosity surround-
ing the star tj Robur Caroli. The places of the small stars in
the Nebulae major and minor, and also those accompanying
the ri Robur Caroli, I ascertained by the mural circle in the
year 1825, at which time I was preparing to commence a ge-
neral survey of the southern hemisphere. These stars being
laid down upon the chart, enabled me to delineate the nebulo-
sity very accurately.

The nebulae are arranged in the order of their south polar
distances to the nearest minute for 1827, and in zones for each
degree in the order of their righ^ ascension. The column on
the right hand shows the number of times the object has been
observed.

The reductions and arrangement have been principally made
since my return to Europe ; and I trust this catalogue of the
nebulae will be found an acceptable addition to that knowledge

284 Mr Durilop's Catahgue of Nebulw and

which the Brisbane Observatory has been the means of putting
the world in possession of, respecting that important and hi-
therto but little known portion of the heavens.

Mr Dunlop then proceeds to give his observations in detail
on no fewer than 629 different nebulae ; but as it is impossible
in a work like this to reprint so large a catalogue, we have se-
lected the most curious and interesting nebulae, and those
which are most likely to attract the notice of the philosopher
in his speculations on the construction of the heavens.

No. 18. R. Asc. 0^ 16™ 28«. S. Pol. Dist. 16° 59'.
47 Toucan, Bode.

This is a beautiful large round nebula, about 8' diameter,
very gradually condensed to the centre. This beautiful globe
of light is easily resolvable into stars of a dusky colour. The
compression to the centre is very great, and the stars are con-
siderably scattered south preceding and north following. —
No. 62. R. Asc. 0*^ 57™ 32^ S. Pol. Dist. 18° 15'.

A beautiful bright round nebula, about 4' diameter, exceed-
ingly condensed. This is a good representation of the 2d of
the Connaissance des Tems in figure, colour, and distance ; it
is but a very little easier resolved, rather a brighter white, and
perhaps more compact and globular. This is a beautiful^
globe of white light ; resolvable : the stars are very little scat
tered.

No. 67. R. Asc. 12'^ 11™ 4^. S. Pol. Dist. 18° 24'.

A star of the 6th magnitude, with a beautiful well-definec
milky ray proceeding from it south following ; the ray is C(
nical, and the star appears in the point of the cone, and th<
broad or south following extremity is circular, or rounded offJi
The ray is about 7' in length and nearly 2' in breadth at th<
broadest part, near the southern extremity. With the sweep-j
ing power this appears like a star with a very faint milky raj
south following, the ray gradually spreading in breadth froi
the star, and rounded off at the broader end. But with
higher power it is not a star with a ray, but a very faint nebu-
la, and the star is not involved or connected with it : I shouh
call it a very faint nebula of a long oval shape, the smaller end'

Clusters of Stars in the Southern Hemisphere. 285

towards the star ; this is easily resolvable into extremely mi-
nute points or stars, but I cannot discover the slightest indica-
tions of attraction or condensation towards any part of it. I
certainly had not the least suspicion of this object being resol-
vable when I discovered it with the sweeping power, nor even
when I examined it a second time ; it is a beautiful object, of
a uniform faint light.

No. 107. R. Asc. 5'^ 52'" 20^ S. Pol. Dist. 19° 46'.

A very pretty double nebula, with a star in the preceding
side of the largest, and a very small star in the south margin
of the smallest nebula.

No. 142. R. Asc. 5*^ 39"^ 30^. S. Pol. Dist. 20° 45^.
30 Doradus, Bode

Is a pretty large ill-defined nebula, of an irregular branch-
ed figure, with a pretty bright small star in the south side of
the centre, which gives it the appearance of a nucleus. This
is resolvable into very minute stars.

N.B. The 30 Doradus is surrounded by a number of
nebulae of considerable magnitudes, nine or ten in number,
with the 30 Doradus in the centre.

No. 152. R. Asc. 5^ 43"^ 50^ S. Pol. Dist. ^0" V.

A cluster of six or seven small nebula?, forming a square
figure 5' or 6' diameter, with several minute stars mixt. This
is a very pretty group of nebula?.

No. 164. R. Asc. 12'^ 49"^ 0«. S. Pol. Dist. 20° 6'.
12 Muscae, Bode.

This is a pretty bright round nebula, about 4' diameter,
moderately condensed to the centre. This, with the sweeping
power, has the appearance of a globe of nebulous matter with
very small stars in the north following margin. But with a power
sufiicient to resolve it, the globular appearance vanishes in a
very considerable degree ; and the brightest and most conden-
sed part is to the preceding side of the centre, with the stars
considerably scattered on the north following side. Resolva-
ble into stars of mixt small magnitudes. A small nebula pre-
cedes this.

No. 175. R. Asc. 5"" 22^" 7». S. Pol. Dist. 21° 50'.

A pretty large rather faint nebula, about 5' diameter, irre-

^tS6 Mr Dunlop's Catalogue of Nebuloe and

gular figure, partly resolvable into stars of mixt magnitudes.
The nebulous matter has several seats of attraction, or rather
it is a cluster of small nebulas with strong nebulosity common
to all.

No. 198. R. Asc. Q^ 6"^ 9.T S. Pol. Dist. *^r m^.
A pretty strong ray of nebula following a small star ; but
the small star is not involved. The ray is about 2' long and
50" broad, with a bright point or nucleus near the preceding
extremity.

No. 9.m. R. Asc. 11^ 40"^ 9^ S. Pol. Dist. 26° 8'.
A very small nebula, very bright immediately at the centre ;
the bright point is nearly equal in brightness to one of the mi-
nute stars north of the nebula. I do not think the bright
point is a star, but a very highly condensed nucleus, surround-
ed by a faint chevelure, not more than 10" diameter. Another
very minute nebula precedes this.

No. 271. R. Asc. llh 11m 36^ S. Pol. Dist. 27°28'.
A rather bright nebula, about 9>y or 3' long and 1' broad,
in the form of a crescent, the convex side preceding ; no con-
densation of the nebulous matter towards any point. This is
easily resolvable into many stars of some considerable magni-
tude, arranged in pretty regular lines, with the nebula remain-
ing, which is also resolvable into extremely minute stars. This
is probably two clusters in the same line. '

No. 278. R. Asc. 16^ 19"^ T- S. Pol. Dist. 27° 18'.
A pretty well-defined small nebula, extending in the parallel
of the equator, rather a little south preceding, and north fol-
lowing, about \^' long, and 25" broad, with a star of the lltH
or 12th magnitude in the centre. The nebula is nearly equallj?
bright, and the star is in the centre.

No. 289. R. Asc. IP 29"^ 20^ S. Pol. Dist. 29° 16'
A pretty large cluster of stars of mixt magnitudes, about'
10' diameter. The greater number of the stars are of a pale
white colour. There is a red star near the preceding side^
another of the same size and colour near the following side;
another small red star near the centre ; and a yellow star near
the south following extremity, all in the cluster.

No. 295. R. Asc. 18*^ 54™ 3'. S. Pol. Dist. 29° 45'.
A pretty large and very bright nebula, 5' or 6' diameter,

Chisters of Stars in the Southern HemAsphere. 287

irregular round figure, easily resolved into a cluster of small
stars, exceedingly compressed at the centre. The bright part
of the centre is occasioned by a group of stars of some consi-
derable magnitude when compared with those of the nebula.
I am inclined to think that this may be two clusters in the
same line ; the bright part is a little south of the centre of the
large nebula.

No. 309. R. Asc. IQh 38"\ 0^ S. Pol. Dist. 3P iW.

■/j Roboris Caroli, Bode.
Is a bright star of the 3d magnitude, surrounded by a mul-
titude of small stars, and pretty strong nebulosity ; very simi-
lar in its nature to that in Orion, but not so bright. The ne-
bulosity is pretty strongly marked ; that on the south side is
very unequal in brightness, and the different portions of the
nebulosity are completely detached, as represented in the figure.
There is much nebulosity in this place, and very much exten-
sive nebulosity throughout the Robur Caroli, which is also
very rich in small stars.

No. 311. R. Asc. W 50^ 30^ S. Pol. Dist. 3P 1&.
A very faint pretty large nebula, about 6' or 8' diameter,
round figure, resolvable into very minute stars. Several stars
of some considerable magnitude appear scattered among the
minute stars of the nebula, but they are only the continuation
of a branch of small stars which run over the place where the
nebula is ; the stars in the nebula are very gradually, but not
much, compressed to the centre.

No. 332. R. Asc. 10'^ 10™ Qk S. Pol. Dist. 33° 57'.

A very faint ray of nebula, about 9! broad, and 6' or T long,

joining two small stars at the south following extremity, which

are very slightly involved, but their lustre is not diminished

: from that of similar small stars in the field. The north ex-

i tremity also joins a group of small stars, but they are not in-

j volved.

! No. 357. R. Asc. 14^ \5^. 0\ S. Pol. Dist. 36° IT.
A very extensive cluster of stars of mixed small magni-
tudes ; the stars appear to be either congregating together in
different parts of the cluster, or breaking up ; there are seve-
] tal groups already formed, the whole cluster is composed of

288 Mr Dunlop's Catalogue of Nehulce and

lines of stars, but no general attraction towards any particular
point.

No. 366. R. Asc. \1^ ST'" 10^. S. Pol. Dist. 36° 25'.

A pretty large nebula, extended nearly in the parallel of
the equator, brightest and broadest in the middle ; a group of
very small stars in the middle give it the appearance of a nu-
cleus, but they are not connected with the nebula, but are si-
milar to other small stars in this place, which are arranged in
groups. The nebula is resolvable into stars.

No. 388. R. Asc. 13^ 36™ 0^ S. Pol. Dist. 39° 32'.

A bright exceedingly well-defined rather elliptical nebula,
about V diameter, exceedingly condensed almost to the very
edge, and gradually a little brighter to the centre. This is
about 6' north of M Centauri. — I have strong suspicion that
this is resolvable into stars.

No. 389. R. Asc. 15^^ 16™ 34\ S. Pol. Dist. 39° 59'.

A very fine round pretty bright nebula, about 3' diameter,
gradually brighter towards the centre, and well-defined at the
margin : this is resolvable. With a power of 260 it has a
beautiful globular appearance. The stars are considerably
scattered on the south side.

No. 408. R. Asc. 0" 47- 35^ S. Pol. Dist. 41° 38'.

A pretty large rather ill-defined nebula, of a round figure,
with a bright point, or small nucleus near the centre ; the ne-
bula is extremely faint almost to the very centre. There is a
star of the 8th or 9th magnitude near the south preceding side,
but not involved.

No. 411. R. Asc. 12^ BB'' 30^ S. Pol. Dist. 41° 31'.

A beautiful long nebula, about 10' long, and 2' broad, form-
ing an angle with the meridian, about 30° south preceding and
north following ; the brightest and broadest part is rather
nearer the south preceding extremity than the centre, and it
gradually diminishes in breadth and brightness towards the
extremities, but the breadth is much better defined than the
length. A small star near the north, and a smaller star near
the south extremity, but neither of them is involved in the ne-
bula. I have strong suspicions that this nebula is resolvable
into stars, with very slight compression towards the centre.
I have no doubt but it is resolvable. I can see the stars,

Clusters of Stars in the Soiithern Hemisphere. S89

they are merely points. This is north following the 1st g Cen-
tauri.

No. 440. R. Asc. 13^^ 16™ 0\ S. Pol. Dist. 43° 26'.
w Centauri (Bode)
Is a beautiful large bright round nebula, about 10' or 1 2' dia-
meter, easily resolvable to the very centre; it is a beautiful globe
of stars very gradually and moderately compressed to the cen-
tre ; the stars are rather scattered preceding and following, and
the greatest condensation is rather north of the centre ; the
stars are of slightly mixed magnitudes, of a white colour.
This is the largest bright nebula in the southern hemisphere.
No. 446. R. Asc. 11^ S^ 55^ S. Pol. Dist. 44° 2V.
A very minute star in the centre of a small round nebula,
about 15" diameter; this has very much the appearance of a
small star surrounded by an atmosphere. There is a similar
small star near the following margin, not involved.

No. 457. R. Asc. 17^ SS'" 40^ S. Pol. Dist. 45° 22^.
A beautiful round nebula, about 5' diameter, with a bright
round well-defined disc or nucleus, about 15" diameter, exact-
ly in the centre; this has the appearance of a planet surround-
ed by an extremely faint diluted atmosphere ; there is a small
star involved in the faint atmosphere ; the atmosphere is at
least 6' diameter.

No. 473. R. Asc. 17^^ 55^^ 14% S. Pol. Dist. 46° 22.
A very bright round highly condensed nebula, about 3' dia-
meter. I can resolve a considerable portion round the margin,
but the compression is so great near the centre, that it would
require a very high power, as well as light, to separate the
stars ; the stars are rather dusky.

No. 482. R. Asc. 13^^ 14™ 44». S. Pol. Dist. 47^ 45'.
A very singular double nebula, about 2^' long and 1' broad,
a little unequal : there is a pretty bright small star in the
south extremity of the southernmost of the two, resembling a
bright nucleus : the northern and rather smaller nebula is faint
in the middle, and has the appearance of a condensation of the
nebulous matter near each extremity. These two nebulae are
completely distinct from each other, and no connection of the
nebulous matters between them. There is a very minute star
in the dark space between the preceding extremities of the

VOL. X. NO. II. APRII^ 1829. T

290 Mr Dunloyrs Catalogue of Nebula; and

nebula ; they are extended in the parallel of the equator
nearly.

No. 486. R. Asc. 18^ 39™ 20^ S. Pol. Dist. 47° 44'.

A very singular body resembling a star, with a very faint di-
luted atmosphere, 8" or 10" diameter; it is paler than a star
of the same magnitude, and precedes a pretty bright star.
No. 501. K. Asc. 17*^ 37"^ 48^ S. Pol. Dist. 48" 4P.

Two very small stars, with a small nebula between them ;
both the stars are involved in the nebula, but the nebula is not
in a line between the stars.

No. 507. R. Asc. 0^ 6™ 50^ S. Pol. Dist. 49° 50'.

A beautiful long nebula, about 25" in length ; position north
preceding, and south following, a little brighter towards the
middle, but extremely faint and diluted to the extremities. I
see several minute points or stars in it, as it were through the
nebula : the nebulous matter of the south extremity is ex-
tremely rare, and of a delicate bluish hue. This is a beauti-
ful object.

No. 508. R. Asc. 5^ 7"^ 0^ S. Pol. Dist. W 45'.

An exceedingly bright, round, well-defined nebula, about 1|'
diameter, exceedingly condensed, almost to the very margin.
This is the brightest small nebula that I have seen. I tried
several magnifying powers on this beautiful globe ; a considera-
ble portion round the margin is resolvable, but the compres-
sion to the centre is so great, that I cannot reasonably expect
to separate the stars. I coxipared this with the 68 Conn, des
Terns, and this nebula greatly exceeds the 68 in condensation
and brightness.

No. 564. R. Asc. 9'^ 8"^ IT. S. Pol. Dist. 53° 53'.

A pretty large faint nebula of a round figure, & or 8^ dia-
meter ; the nebulosity is faintly diffused to a considerable ex-
tent. There is a small nebula in the north preceding side,
which is probably a condensation of the faint diffused nebulous
matter ; the large nebula is resolvable into stars with nebula
remaining.

No. 573. R. Asc. 18^^ 49" 15«. S. Pol. Dist. 53° 10^

A beautiful bright round nebula, about Sy diameter, mo-
derately and gradually condensed to the centre. This is re-
solvable. The moderate condensation, and the bluish colour

Chisters of Stars in the Southern Hemisphere. 291

of the stars which compose it, give it a very soft and pleasant
appearance. This is rather difficult to resolve, although the
condensation is not very great.

No. 588. R. Asc. 19^^ 58" 30^ S. Pol. Dist. 54^ 7-

A very curious nebula, very faint and well-defined, with an
exceedingly bright point in the centre, resembling a small
star surrounded by an atmosphere about 30" diameter ; the
bright point is exactly in the centre, a bright star IS' or 15'
south.

No. 611. R. Asc. 1# 51" 8«. S. Pol. Dist. 5T 39'.

A very singular body resembling a star with a burr. The
light is equal to that of a star of the 7th and 8th magnitude,
and the diameter is not sensibly larger, with various magnify-
ing powers. This has the appearance of a bright nucleus, sur-
rounded by a strong brush of light ; and the nebulosity sur-
rounding the bright point has not that softness which nebula?
in general possess. I consider this different from nebulae in
general.

No. 628. R. Asc. 13"^ 15"' 3^. S. Pol. Dist. 61° 2^.
185 Centauri (Bode.)

Is a very beautiful round nebula, with an exceedingly bright
well-defined planetary disk or nucleus, about T or 8'' diame-
ter, surrounded by a luminous atmosphere or chevelure, about
& diameter. The nebulous matter is rather a little brighter
towards the edge of the planetary disk, but very slightly so.
I can see several extremely minute points or stars in the che-
^ velure, but I do not consider them as indications- of its being
resolvable, although I have no doubt it is composed of stars.

He next proceeds to give the following description of the
famous Magellanic clouds under the name of Nebula Minor
and Major.

The Nebula Minor, to the naked eye, has very much the
appearance of a small cirrus-cloud; and through the tele-
scope, it has very much the appearance of one of the brighter
portions of the Milky Way, although it is not so rich in stars
of all the variety of small magnitudes, with which the bright-
jer parts of the Milky Way in general abound, and therefore it

^2 Mr Dunlop's Catalog'iie q/' Nehulce and

is probably a beautiful specimen of the nebulosity of which
the remote portion of that magnificent zone is composed.

Its situation in the heavens is between 0'' 27' and 1'^ 6' or
T in right ascension, and between 74° 30^ and 72° 53' in south
declination. Its position is oblique to the equator, south pre-
ceding and north following ; and its form is nearly that of a
parallelogram about two degrees long and fully one degree
broad, and may be arranged according to its natural general
appearance, into bright, faint, and very faint nebulosity. The
bright nebula forms the south extremity and the preceding
side, and is equal to the breadth of the nebula at the south
end, and gradually diminishing in breadth and brightness till
it termifiates in an accumulation of the nebulous matter in the
north extremity. The bright portion of the nebulous matter
is not uniformly bright, but has something the appearance of
small cumular clouds, although not very decidedly marked,
and which I cannot well delineate. The faint nebula which
is on the following side, is broad at the north extremity and
gradually diminishing in breadth to where, with the other
faint shade, it joins the following side of the brighter portion
of the nebula, near the south extremity. The very faint shade
is also on the following side, and extends from the northern
to the southern extremity of the nebula, and is rather more
Strongly marked at what I would call its terminating border,
than where it joins or blends with the faint shade ; and I sus-
pect it is faintly connected with a patch of faint nebula which
follows at a little distance.

There are two pretty bright small nebulae situated in the
following margin of the bright shade, and a considerable num-
ber of faint nebulae and accumulations of the nebulous matter
variously situated throughout, and also in the patch which
follows ; but they are described in the general catalogue.

The figure of the Nebula Major is so irregular, and divided
into so many parcels, that without the assistance of letters of
reference it will be impossible for me to attempt a description.
However, the appearance and construction of the different ne-
bulae which compose it, are more minutely described in the ge-
neral catalogue. I will here only attempt to describe the ap-
parent connection of one portion or branch of the nebulous

Clusters of Stars in the Southern Hemisphere. 29'^

matter with another. I find the existence of extensively dif-
fused faint nebulosity throughout a great portion of this quar-
ter of the heavens, from the Robur Caroli to the Nebula Ma-
jor, and I can even trace its existence in the vicinity of Nebu-
la Minor.

The Nebula Major is situated between 4^1 46' and 6'^ 3' in
right ascension, and between Q&^ 30' and 71° 30' of south de-
clination ; but the body or principal portion of the nebula is
situated between 5'^ 7' and 5>^ 40' in right ascension, and be-
tween 69° and 71° of south declination, and is composed of
very strong bright nebula, very rich in small nebulae and clus-
tering stars of all the variety of small magnitudes : I compar-
ed this portion of the nebula Avith Sobieski*'s Shield, which in
this latitude is near the zenith. The observation says, " The
Nebula Major very much resembles the brightness in Sobies-
ki's Shield ; it is scarcely so large, but I think it is equally
bright." Another observation says, " The ridge or brighter
portion of Nebula Major is more condensed than the Shield." ,

The bright ridge or body of the nebula is extended obli-
quely to the equator, north preceding and south following,
and the following extremity breaks off rather suddenly, faint,
decreasing in brightness in a south following direction to the
distance of fully a degree and a half towards the star /5, which
is slightly involved in the narrow extremity : preceding the
star marked 7, a considerable increase of the brightness of the
nebulous matter takes place ; another accumulation takes place
at b about 15' diameter. There is a small star north with a
small nebula preceding, but neither of them are involved in
the accumulation of the nebulous matter, b and £ are connect-
ed by streams of unequal brightness, g is pretty large and is
rich in small stars and nebulae : opposite h and s, towards the
principal body of the nebula, the nebulous matter is very faint
and of unequal brightness ; s is south following a beautiful
group of nebulae of various forms and magnitudes, on a ground
of strong nebulosity common to all, with the 30 Doradus (Bode)
in the centre.

South of the 30 Doradus a pretty bright accumulation of
the nebulous matter takes place, extended, preceding and fol-
lowing, and is joined by pretty strong nebula to the arm x,

294 Mr Duiilop's Catalogue of Nebulae and

which proceeds in a northerly direction from the body of the
nebula ; the bright star near the north extremity of the arm
is not involved in the bright nebula. Between the arms % and
X the nebula is very faint, and the bright accumulations of the
nebulous matter on the north side are all connected together
by nebulosity of various brightness, and are connected to the
main body by the arms x and X ; and I strongly suspect the
nebula at (p is connected by very faint nebula with the group
surrounding the 30 Doradus. The accumulation of the nebu-
lous matter at t, is connected with the preceding extremity of
the body of the nebula, by nebula increasing in brightness to-
wards the neck of the body, but I cannot say that the -^ is
connected with the g. Two arms proceed from the neck to-
wards the south, which are connected by faint nebula between
them, which gradually increases in brightness towards the
junction of the arms; between the arm ri and the body, the
nebulosity is faint, of various shades of brightness, and from
the arms n and v, to the head g, the nebulosity is of various
degrees of brightness.

I have made a very good general representation of the va-
rious appearances of the Milky Way, from the Robur Caroli to
where it crosses the zenith in Scorpio. This was generally
made by the naked eye, except in particular places where I
suspected an opening or separation of the nebulous matter,
when I applied the telescope. However, the dark space on
the east side of the Cross, or the black cloud as it is called, is
very accurately laid down by the telescope ; the darkness in
this space is occasioned by a vacancy or want of stars ; it con-
tains only two or three of the 7th magnitude, and very few of
the 8th or 9th magnitude. I may here remark that the Ne-
bula Minor is not so bright as the Nebula Major.

Neither of the two nebulae, Major and Minor, are at present
in the place assigned to them by Lacaille ; and it has been
suspected that nebulous appearances change their form and
also their situation. Yet, although the situation of these ne-
bulae, as given by Lacaille and compared with their present
situation, would be favourable to such a surmise, still we must
consider the dimensions of the instruments with which he made
his observations, and make a reasonable allowance.

Clusters of Stars in the Southern Hemisphere, 295

However, the 30 Doradus is at present involved in pretty
strong and pretty bright nebula, and is also situated very near
the brightest part of the Nebula Major ; and it would be singu-
lar if its relative situation was the same when Lacaille observed
it as it at present is ; that he should have assigned to it a place
in the Dorado and not in the Nebula Major, to which, from its
nature, it was not only nearly allied, but in which it was actual-
ly involved. This circumstance, it must be confessed, is fa-
vourable to the conjecture ; and the 47 Toucani is similarly
situated, with respect to distance, from the Nebula Minor, al-
though it is not involved in nebulosity or connected witli tlie
nebula.

When reflecting on these circumstances, I was led to exa-
mine the present state of these nebulae, and find that scarcely
any nebulse exist in a high state of condensation, and very few
in a state of moderate condensation towards the centre. A con-
siderable number appear a little brighter towards ^the centre,
and several have minute bright points immediately at the cen-
tre. Others have small or very minute stars variously situated
in them, but many of those bright points in or near the cen-
tre may be stars, for the Nebula Major in particular is very
rich in small stars. But the greater number of the nebulae
appear only like condensations of the general nebulous matter,
into faint nebulae of various forms and magnitudes, generally
not well-defined ; and many of the larger nebulous appear-
ances are resolvable into stars of mixed small magnitudes ; and
a great portion of the large cloud is resolvable into innumera
ble stars of all the variety of small magnitudes with strong ne-
bula remaining, very similar to the brighter parts of the Milky
Way. And whether the remaining nebulous appearance may
not be occasioned by millions of stars disguised by their dis-
tance, is what I cannot say.

But a critical examination of these nebulae would not only
be a valuable treasure for the present generation to possess,
but an invaluable inheritance for them to transmit to posterity.
For it must be by the comparison of observations, made at dis-
tant periods of time, that we can draw any satisfactory conclu-
sions concerning the breaking up or the greater condensation
of the nebulous matter. It seems beyond a doubt that stars

296 Mr Herschers Table of the

must assume a nebulous appearance when situated at immense
distances ; but whether all nebulous appearances are occasion-
ed by stars, is a problem apparently beyond the reach of man
to resolve, without the assistance of analogy, which ought not
to be trusted too freely, especially with objects almost equally
beyond the reach of our hands and telescopes. Several of the
very faint and delicate nebulae can be resolved into stars, and
also many of the brighter nebulae are composed of stars ; but
there are a greater number which have not yet been resolved
or shown to consist of stars ; and it is not improbable, that
" shining matter may exist in a state different from that of the
starry."

Art. XV. — Table of the Refractive Powers of several Bodies,
according to the observations of J. F. W, Herschel, Esq,
F. P. R. S. Sfc. With remarks by the Editor.

In his Treatise on Light, Mr Herschel has published a very
copious table of refractive powers, compiled from the observa-
tions of preceding authors, and he has inserted in it vari-
ous observations of his own, which, from the accuracy with
which they were made, possess very great value. From the
importance which is now beginning to be attached to the opti-
cal properties of minerals, as affording the most precise dis-
tinctive characters, both our optical and mincralogical readers
will be glad to see these measures of Mr Herschel collected
from the table in which they occur.

Table of Mr HerscheVs Measures of the Refractive Powers of
several Bodies*,

Saturated aqueous solution of alum, - - 1 .356

Alcohol (rectified spirits,) _ _ - J. 372

Muriatic acid (spec. grav. 1.134,) - - - 1.392

Sulphuric acid, - - - - 1.430

Oil of turpentine (common,) - . - 1.486

Oil of olives, - - - - * ' 1.4705

Nut oil (perhaps impure,) , . _ 1.490

* From his Essay on Light, §.1116.

Refractive Powers of several Bodies. 29*?

Rochelle salt (mean green rays,) - - 1.4985

. . (mean red,) - - - . 1.4929

English plate glass (extreme red,) - - 1.513S

Crown glass, a prism by Dollond (extreme red,) 1.526

another do. do. - 1.5301

Apophyllite (leucocy elite,) _ - - 1.5431

Hyposulphate of lime (mean red,) - - 1.561

. (mean yellow green,) - 1.566

Flint glass, - - . _ - 1.578

' a prism by Dollond - - > 1.589

. (extreme red,) - 1.585

I a prism by Dollond (extreme red,) - 1.601

do. marked " heavy" (extreme red) - 1.602

Hyposulphite of lime, least refraction, - - 1.583"

greatest refraction, - 1.628

■ strontia, least refraction, - - 1.608

greatest refraction, - 1.651

Sulphate of barytes, ordinary refraction (along the axis)

for yellow green rays, _ - - 1.6460

. another specimen do. red rays, 1.6459

for yellow green rays, - 1.6491

Chloruret of sulphur, . _ _ - 1.67

Nitrate of bismuth, least refraction about - 1.67

■ greatest about - 1.89

\ Hyposulphite of soda and silver, least refraction, 1.735

. __ greatest do. - 1.785

Spinelle ruby, . - - - 1.756

Rubellite, ... - - 1.768

Labrador hornblende, - - - - 1.80

Silicate of lead, atom to atom, - - 2.123

Nitrate of lead (bioxal, ? quadro-nitrate) or six-sided

prisms, ordinary refraction, . - - 2.322

At the end of the table from which the preceding measures
are taken, Mr Herschel has made the following appropriate
remarks.

" In casting our eyes down the foregoing table, we cannot
but be struck with the looseness and vagueness of those re-
sults which refer to bodies whose chemical nature is in any
respect determinate. The refractive indices assigned to the

29a Mr HerschePs Table of the

different oils, acids, &c. though no doubt accurately determin-
ed from the particular specimens under examination, are yet,
as scientific data, deprived of most of their interest from the im-
possibility of stating precisely what was the substance exa-
mined. Most of the fixed oils are probably (as appears from
the researches of Chevreul) compounds in very variable pro-
portions of two distinct substances, a solid concrete matter
(stearine,) and a liquid (elaine,) and it is presumable that no
two specimens of the same oil agree in the proportions. This
is probably, peculiarly the case with the oil of anise-seed*,
which congeals almost entirely with a very moderate degree
of cold. An accurate re-examination of the refractive and dis-
persive powers of natural bodies, of strictly determinate chemi-
cal composition, and identifiable nature, though doubtless a
task of great labour and extent, would be a most valuable
present to optical science."

At the end of the table of dispersive powers, which Mr
Herschel gives from Dr Brewster's Treatise on New Philosophy
cal instruments, he adds " respecting the results in this table,
the remark applied to that of refractive indices may yet be
more strongly urged. The whole stands in need of a radical
reinvestigation.'"

Although we entirely agree with Mr Herscliel in all these
remarks, yet, as they are particularly applicable to our ob-
servations, which form the greater part of the tables referred
to, we think it necessary to add the following explanations.
• In order to obtain uniform measures of the refractive pow-
ers of oils and other fluids, it is absolutely necessary to deter-
mine their specific gravities, and the temperatures at which
the observations are made. But even if we do this, we shall
find that the same oil, especially if it is procured in small
quantities, will give different results, even at the same tempe-
rature. The more volatile parts fly off, and the oil becomes
inspissated, and has a higher refractive power. We have now

• As a proof of the correctness of this remark, I may observe, that the

oil of anjse-seed, whose refractive and dispersive power I measured, and

which I have used in various optical inquiries, never congealed. That

which I am using now, and which I consider pure, congeals entirely at

60° Fahr.— D. B.

Refractive powers of several Bodies. 299

^jefore us oils purchased in 1810, and which have no resem-
blance to similar oils which are now obtained under the same
name. Some of them, indeed, have deposited groups of crys-
tals, and consequently they must have become almost new
substances.

In the examination of gums, and such like hard solids, their
refractive power depends on the degree of induration which
they possess, and this will depend on th6 place where they have
been kept ; so that the same gum will give different results at
different times.

In the case of minerals, every thing depends on the nature of
the specimens which the observer can command. I have often
been compelled to measure both refractive and dispersive pow-
.ers with fragments not bigger than a pin's head, and with crystals
that almost escaped unassisted vision. At -other times, I have
been obliged to work with specimens which I was not allowed
to cut, and in this case, when the natural faces were imper-
fect, there was no resource but to take a mean of the inclina-
tions of different parts of the faces, and a mean of the angle of
deviation, or, what is sometimes better, to mask with an opaque
cement all the imperfect portions of the surface, excepting
those which had the best polish, and the most uniform incli-
nation.

On other occasions, it was necessary to keep the crystal in
its matrix, and to resort to the most troublesome methods of gain-
ing a measure of its refractive or dispersive powers. All this
labour, however, and none but those who have been exposed
to it can form an idea of it, was not undergone to obtain mere-
ly a measure of refractive indices, or of dispersive actions, but
for purposes much more important, and more interesting to
the observer. This circumstance leads us to consider the va-
rious objects for which such measurements are taken.

1. When refractive or dispersive powers are measured to
determine physical or chemical relations, numerical accuracy
is of no importance. When Sir Isaac Newton, for example,
deduced from his refractive indices of camphor, olive oil, lin-
seed oil, spirit of turpentine, amber, and the diamond, his beau-
tiful conclusion that the latter was probably an inflammable
substance coagulated, the measures of the merest tyro would

300 Mr. Herschers Tabic of Refractive Powers, S^c.

have been sufficient authority for the conchision. Had Sir
Isaac made the index of diamond 2.000 in place of 2.439, and
that of camphor 1.400 in place of 1.500, he would have ar-
rived at the very same result.

2. When I concluded from my table of refractive powers,
that the refractive pozvers of the three simple inflammable sub-
stances, viz. DIAMOND, PHOSPHORUS, and SULPHUR, are in the
order of their inflammability, I had no other results but a coarse
measure of the influence of the two latter substances in altering
the focal length of the object-glass of the microscope, (the influr
ence being measured by the numbers 4.337 for sulphur, and
7.094 for phosphorus,) and these numbers were as good evi-
dence of the general principle as if sulphur and phosphorus
had been capable of being wrought into the purest transparent
prisms, and had their refractive powers determined in relation
to the fixed lines in their spectra.

3. In determining the relation between the index of refrac-
tion and the polarizing angle of bodies, the ordinary measures
were quite sufficient for the purpose, and on their authority
the law has been universally adopted.

4. When refractive and dispersive powers are measured to
discover substances proper for achromatic telescopes and mi-
croscopes, a very rude measure is all that is necessary. When
I found that sulphuret of carbon possessed most valuable pro-
perties, and when I recommended it as a fluid " which might
yet be of incalculable service in the construction of optical in-
struments," I had taken only the ordinary measures of its ac-
tion upon light ; and the practical optician requires no better
evidence of the suitableness of the fluid for the construction of
fluid object-glasses.

6. When refractive and dispersive powers are required to
enable the practical optician to calculate the curves for an
achromatic combination, the greatest accuracy is required ;
but in such a case he durst not trust to the measurements of
Newton, or Boscovich, orDollond, or Wollaston, or Herschel,
or even to those of Fraunhofer, the most accurate of all, be-
cause there is no possibility of his commanding the same ma-
terials with which their experiments were made. He has no
alternative, therefore, but to measure with his own hands the

Mr Dunlop'*s Jpproa^imate places, 4*c. 301

refractive and dispersive powers of the materials which he
means to employ.

From these observations we have no hesitation in conclud-
ing, that the existing tables of refractive and dispersive powers,
with all their imperfections and errors, are of great use in sci-
entific researches. If they do not afford scientific data on
which the philosopher may confidently rest, they furnish him
with approximate results, and general indications; and are per-~
haps the more valuable to him, that they compel him to as-
certain the properties of the materials themselves with which
he works, or about which he reasons.

Now that mineralogy depends in a very great degree on the
determination of the physical characters of the bodies which
it embraces, we are on this account anxious to see new tableis
of refractive and dispersive powers ; and we would strongly re-
commend the subject as one that would establish the reputa-
tion of any young philosopher who has the courage to devote
himself to so laborious a task.

Art. XVI. — Approximate Places of Double Stars in the
Southern Hemisphere observed at Paramatta in New South
Wales. * By James Dunlop, Esq. In a Letter to Sir T.
Macdougal BuisBANE, K. C. B., F. R. S. Lend, and Ed.

Sir,

In presenting this list of double stars, it may be necessary for
me to make some apology for its imperfect state, as regards the
true apparent distance and position of a great many of the dou-
ble stars, the situation of which it points out in the heavens.

You are aware that during your administration of the govern-
Jpfimt of the colony of New South Wales, my time and attention
were wholly devoted, in your employ, to the Paramatta observa-
tory in the miscellaneous observations which occurred ; and
principally in observing the right ascensions and polar distances
of the fixed stars, thereby collecting materials towards the for^
BQation of a catalogue of stars in that hemisphere (which mate-

* Abridged from the Transactions of the Astronomical Society of Lon-
don. Read May 9, 1828.

302 Mr Dunlop's Approwimate Places

rials have been presented by you to the Royal Society of Lon-
don) : and your departure from the colony alone prevented me
from pursuing that branch further.

Finding myself in possession of reflecting telescopes, which I
considered capable of adding considerably to our knowledge of
the nebulae and double stars in that portion of the heavens, I
resolved to remain behind to prosecute my favourite pursuits,
in collecting materials towards the formation of a catalogue of
the nebulae and double stars in that hemisphere, and any other
object which might have attracted my attention.

The nebulae being a primary object with me, I devoted the
whole of the favourable weather in the absence of the moon to
that department, and the moonlight, in general, was allotted to
the observations of double stars ; a portion only of which I have
been able to subject to the various measurements necessary for
the accurate determinations of their relative distances and posi-
tions.

In the case of the stars marked with an asterisk, their posi-
tions, distances, declinations, &c., are the result of micrometrical
measurements with the 46-inch achromatic telescope mounted
on the equatorial stand which you left with me: the micrometers
were constructed by myself, consisting of a parallel line micro-
meter, the screws of which I bestowed great pains upon, and
which I consider very excellent and uniform ; also a double
image micrometer on Amici's principle, which I sometimes used,
particularly when the stars were nearly of equal magnitudes (I
always found some uncertainty in the measurements, when the
stars were of very unequal magnitudes) : the position microme-
ter was made by Bancks, and belongs to the telescope.

In the case of those stars which are not marked with an
asterisk, their positions and distances are only estimations while
passing through the field of the 9-feet telescope : in the various
sweeps, the right ascensions and declinations are also those
which were indicated by the same instrument fitted up and de-
scribed as a meridian telescope, in my paper on the nebulae of
the southern hemisphere.

I will only extend at length the observations of a few of the
principal stars, merely to show the manner in which they have
been conducted.

of Double Stars in the Southern Hemisj)here. 303

Trusting that my humble efforts will be of some service to
science, I have the honour to be, Sir, your obedient servant,

James Dunlop.

R. Asc. Oh 23"^ ; Decl. 63° 6^^ S.
1 and 2 jS Toucani. Both of the 4th magnitude.
Both light yellow.
Angle of Position, 84° 5' North Preceding.
Diff. of R. Ascension, 0%607.
Diff. of Declination, M%S65.

R. Ascen. !> 32"^ ; Decl. 58° 18' S.
100 Phcenicis. Double ; 6th and 8th magnitudes.
; Angle of Position, 17° 27 South Following.

Distance, 15%809.

R. Asc. Ih 33"^ ; Decl. 57° 4' S.
6 Eridani. Double ; both of the small 6th magnitude.

Angle of Position, 73° 6\
A beautiful double star ; both stars white ; the preceding a
little dusky. I cannot say which of the stars is the larger ; per-
haps the following, if there be any difference. The distance is
about equal to one diameter of the following star, which I esti-
mate at about 2 J seconds.

R. Asc. 2^ 51"^ ; Decl. 41° 0' S.
& Eridani. Double ; 4.5 and 6th magnitudes.
Large white ; small yellow.
Angle of Position, 1^ 37' North Following.
•; Distance, 10%81.

R. Asc. S^ 33"^ ; Decl. 40° 55' S.
184 Eridani. Double ; 6th and 7th magnitudes.
Large white ; small blue. Very pretty.
][, Angle of Position, 64° 55' North Preceding.

Distance estimated at 4".

R. Asc. S^ 42"^ ; Decl. 38° 10' S.

^07 Eridani. A beautiful double star; 5th and 5. 6th magnitudes.

Both light yellow.

Angle of Position, 67° 48' South Preceding.

Distance estimated at 7".

304 Mr Dunlop's Approximate Places

R. Asc. 4^ 46-^ ; Decl. 53° 46' S.
Pictoris. Double ; 6th and 7th magnitudes.

Large white ; small blue.
Angle of Position, 30° 4' North Following.
Distance, 12%547.
Diff. of R. Ascension, V\ 1 37-
Diff. of Declination, 8^659.

R. Asc. 5^ 26- ; Decl. 42° 26' S.

9,6 Pictoris. Double ; little unequal. Both of the small 6th

magnitude.

Bluish white.

Angle of Position, 80° T South Following. .

Distance, 5",534.

R. Asc. 7'' SI'" ; Decl. 26° 26' S.
X ArgHs. Double ; very nearly equal. 4th magnitude.
Both white.
Angle of Position, 45° 48^ North Preceding.
Distance, 8", 765.
N. B. Sometimes the stars appear sensibly unequal, and on
other nights I cannot say which star is the larger.

R. Asc. lO^^ 28^" ; Decl. 71° 13' S.
Double ; very nearly equal. 8th and 8th magnitudes.
Angle of Position, 41° 11' South Preceding ;
Distance, 3",695. ,

R. Asc. 10^ 38"^ ; Decl. 5^° 43' S.
93 Rohoris Ca/roli. Double ; 3d and 10th magnitudes.
Angle of Position, 79° 9! North Following ;
Distance, 60",20.

R. Asc. li'^ 24- ; Decl. 28° 19^ S.
^75 HydrcB. Double ; very nearly equal. Both of the small
6th magnitude. ^

Large yellow ; small blue. 1

Angle of Position, 61° 25' North Following.
Distance, 9",965,
Diff. of R. Ascension, 0",20.
Diff. of Declination, &\9B9.
3

of Double Stars in the Southern Hemisphere. 305

R. Asc. 12^ le'" ; Decl. 62° T S.

a Crucis. Triple ; 2d, 2.3cl, and 6th magnitudes.

Observations on the 2d and 2.3d magnitudes.

Both yellowish white ; smaller rather pale.
Angle of Position, 24° 24/ South Following.
Distance, 5",55.
N. B. Castor and a Crucis are double stars very similar to
one another in point of magnitude, colour, and distance. The
following comparison was made on the 26th March 1826, by
the double image micrometer.

Distance Castor, 5",375.
Distance a Crucis, 5",292.

R. Asc. 12*^ 16"^ ; Decl. 62° T S.
a Crucis. Double ; 2d and 6th magnitudes.

Large white ; small reddish yellow.
Angle of Position, 70° 0' South Preceding.
Diff, of R. Ascension, 4", 45 ;
Diff. of Declination, 81'',473.
Mr Fallows mentions this star accompanying a Crucis as a
star of the small 4th magnitude. I have never observed it for
a star of more than the 6th, and frequently as a star of the 6.7th
magnitude. I have never suspected it as *a variable star.

d Pictoris. R. Asc. 5^ 20"^ ; Decl. 58° 28' S.
5.6 and 6.7 m. L. yellow ; S. bluish white.
Angle of position, 14° 4/ North Preceding.
Diff. of R. Ascension, 4",19.
Diff. of Declination, 9'',055 ;
Distance, 38%516.

7 Crucis. R. Asc. 12^^ 21"^ ; Decl. BG"" 7 S.
2 and 6.7 m. L. dusky red ; S. pale.
Angle of Position, 46° 42' North Following.
Diff. of R. Ascension, T',216;
Diff. of Declination, 70",854.

0 Crucis. R. Asc. 12'^ 44'" ; Decl. 56"" 13' S.
5 and 6 m. Both white.
Angle of Position, 79° 48' North Following.
Diff of R. Ascension, 1^^,375 ;

VOL. X. NO. II. APRIL 1829. U

306 Mr Dunlop's Approximate Places

DifF. of Declination, 3^,51 ;
Distance, 35,97.

k Centauri, R. Asc. 13" 42"^ ; Decl. 32° 9' S.

5.6 and 8 m. L. white ; S. blue.
Angle of Position, 30° KT South Following.
Diff. of R. Ascension, (time) 0",57 ;

(arc) 6^97 ;

Diff. of Declination, 4",4<25.

Y Centauri R. Asc. 14'> 10™ ; Decl. 57° 40' S.

5 and 8 m. L. yellow ; S. pale.
Angle of Position, 70° 55' South Following.
Diff. of R. Ascension, 0",15 ;
Diff. of Declination, 9",58 ;
Distance, 12",789.

a Centauri. R. Asc. 14»' SS'" ; Decl. 60° & S.

1 and 4 m. Both strong reddish yellow.
Angle of Position, 56° 49' South Preceding.
Diff. of R. Ascension, 1",783 ;
. Diff. of Declination, 18",788.

I Lupl R. Asc. 14h 59'" ; Decl. 51° 25' S.
5 and 8 m. L. greenish yellow ; S. pale.
Angle of Position, 20° 48' North Preceding.
Diff. of R. Ascension, 7",38 (time.)

64'',! 95 (arc.)

Diff. of Declination, 24",47 ;
Distance, 68",79.

X Lupi. R. Asc. 15h 0"^ ; Decl. 48° 1^ S.
5 and 7 m. L. greenish yellow ; S. reddish yellow.
Angle of Position, 55"" 40' South Following.
Diff. of R. Ascension, 1^397;

16",92 ;

Diff. of Declination, ^',563;
Distance 28",88.

,L Lupi. R. Asc. 151^ 6~ ; Decl. 47° 13' S.
Angle of Position, 64° 36'' South Following.
Diff. of R. Ascension, 1",50 ;

of Double Stars in the Southern Hemisphere, 307

DifF. of R. Ascension, 18",88 ;
DifF. of Declination, 1^613. .

g Lupi. R. Asc. 15^ m^ ; Decl. 33° 30' S.
A beautiful double star. Both of the small 6th magnitude ;
, ^. little unequal. L. slightly yellow ; S. greenish.
Angle of Position, 40° 43^ North FpHowing.
Diff. of R. Ascension, 0",70 ;

r,36;

DifF. of Declination, T,^2^ ;
On another night 6%831.

^ Piscis Australis. R. Asc. 22*' 21 •" ; Decl. 33° 14' S.
Angle of Position, 82° 46^ South Following.
Difi: of Declination, 27%68 ;
Distance, 35'',31.

4. Gruis. R. Asc. 23'^ 13™ ; Decl. 54*' 49'' S.
6 and 7 m. L. dusky ; S. blue.
Angle of Position, 58° 24^ South Preceding.
DifF. of Declination, 22''',73 ;
Distance, 27%09.

& Phcenicia. R. Asc. 23^ 30'" ; Decl. 47° 36' S.
6 and 6 xn. ; very nearly equal. L. white ; S. bluish. Po-
sition preceding, in the parallel of the equator. Distance about
J \ diam. of the larger star.

<p Sculptoris. R. Asc. 23*' 46'" ; Decl. 28° 26' S.
Both of the small 6th magnitude ; a little unequal. Both
bluish white.

Angle of Position, 0° 0' exactly preceding.
Distance, 5",031 4 obs.; DifF 0%75.
Nothing is more remarkable than the different colours of the
stars as observed by Mr Dunlop. The following are some of
the colours mentioned in the Catalogue.

Uncommon red purple. Blue.

Fine yellow. Greenish.

Pale green. White.

Dusky red.
Mr Dunlop's valuable memoir is then concluded with a detail-
ed catalogue of 253 double stars.

308 Mr Herschers Experimenf on the

Art. XVII. — Jccourit of an Experiment made on the composi-
tion of Oil of Cassia, to determine the cause of its high disper-
sive power ^* by J. W. F. Herschel, Esq. V.P.R.S. Sfc. <5c

When the extraordinary dispersive power of Oil of Cassia
was discovered by Dr Brewster, he made the following obser-
vation on it:

" The substances at the head of the table between the dis-
persive powers of 0.0128 and 0.400, (these numbers are values
of ^^J have never before been the subject of experiment, and
present us with results of unexpected magnitude. Chromate
of lead, realgar, and phosphorus, which are included within
these limits, might, from their chemical properties, be supposed
to possess a great degree of dispersion ; but the oil of cassia,
which exceeds even phosphorus in dispersive power, and stands
far above every mineral or vegetable product, exerts a most
surprising power in separating the extreme rays, and indicates
the existence of some ingredient which chemical analysis has not
been able to detect."" •\'\

After the same author \\2ididisco\eve&i\\2itSulphuret of Carbon
exceeded oil of cassia in refractive power, that of the former
being 1.68, and that of the latter only 1.64; while oil of
cassia exceeded the sulphuret in dispersive power, that of the
former oil being 0.139, and that of the sulphuret 0.1 15, he
remarks : —

" All other fluids are separated from these two in their op-
tical properties by an immense interval ; and hence we are of
opinion, that oil of cassia will yet be found to consist of in-
gredients as remarkable as those which enter into the compo-
sition of sulphuret of carbon." J

As the oil of cassia possesses also the remarkable property
of acting less powerfully upon green light than upon any other
substance yet known, § it became very interesting to determine
the principle to which such singular properties were owing.

• From his Essay on IJifht, § 1 122.

+ Treatise on New Philosophical Instruments, p. 310.

X Edinburgh Transactions, vol. vii. p. 288.

§ Id. vol. viii. p. 11.

Composition of O'd of Cassia. 309

This has been accomplished by Mr Herschel in a very inte-
resting experiment, of which he has given the following ac-
count:—

" The following experiment would seem to point out the %-
drogen of the latter oil (oil of cassia) as the principle to
which its extraordinary dispersion is due, and is otherwise in-
structive, as exemplifying strongly the independence of the two
powers inter se. A stream of chlorine was passed through oil
of cassia till it refused to act any farther. The oil was at
first greatly deepened in colour; but as the action proceeded,
it changed to a much lighter ruddy yellow, which it retained
till the action was complete, (and which in a few days changed
to a fine rose red.) Copious fumes of muriatic acid gas were
given off during the whole process, indicating the abstraction
of abundance of hydrogen, and at length the oil was converted
into a viscous mass, drawing out into long threads, having
entirely lost its peculiar perfume, and acquired a pungent pe-
netrating scent, an acrid astringent taste, totally unlike its for-
mer aromatic flavour. It was inflammable, though less than
before, burning with a flame green at the edges, indicating the
presence of chlorine. Its refractive power was very little di-
minished. A drop being placed in the angle of two glass
plates, and close to it a drop of unaltered oil of cassia, the
spectrum of a line of light was viewed at once with the same
eye through both the media. They still formed a conrtinuous
line, the spectrum of the unaltered oil being more refracted by
only about one-fourth the breadth of that of the altered speci-
men. But the dispersive power of the latter was most remark-
ably diminished, being brought below not only that of the un-
altered oil, but even below that of flint glass. When the disper-
sion of the unaltered oil was corrected by flint-glass, that of the
altered was found to be much more than corrected ; and when
the angle of the glass plates was such that the dispersion of
the latter was just corrected by a prism of Dollond's ^ heavy'
"flint, whose refracting angle = about 25°, the uncorrected
spectrum of the former was about equal to that of the flint
prism. The dispersion, then, had been diminished to half its
former amount, while the refraction had sufl'ered hardly any
appreciable change. — (October 7, 1827.^

310 Contributions to Physical Geographic .

Aet. XVIIL- — Contributions to Physical Geography.
1. Account of' the Eruptions of Mount uEtna.* By L. Simond.

It seems probable that in Homer's time ^Etna was an extinct
volcano, as Vesuvius continued to be to a much later period ;
for Homer, speaking of ^tna, says nothing of its fires."|- Sub-
sequently, however, Thncydidcs preserved the memory of three
great eruptions, and Diodorus recorded another which had ta-
ken place in the first year of the 96th Olympiad. One hun-
dred and twenty-two years before Christ, the earth shook and
vomited fires even under the sea, and vessels perished near the
coast of Sicily. In Caesar's time a great eruption took place,
perhaps two ; as at his death, we find, the earth shook and the
air was obscured. The eruption in the 44th year of our aera
was recorded by Suetonius, only because it had made Caligula
run away from Messina ; and that of the year 812 was only
remembered for a similar cause, no less a personage than
Charlemagne having likewise been frightened.

In the intermediate time (the year 252) torrents of liquid
fire running down the sides of JEtna turned away at the tomb
of St Agatha, an indigenous female saint who the year before
had suffered martyrdom on the spot. Possibly volcanic erup-
tions were as frequent as in modern times, but no one cared
then about natural phenomena of any sort, unless connected
with such great matters as the fright of an emperor or the
glory of a saint.

Only two eruptiotis are recorded in the twelfth century, one
in the thirteenth, two in the fourteenth, four in the fifteenth,
and four in the sixteenth. During the last part of the fifteenth
century and the first part of the sixteenth, a period of ninety
years intervened without any. Twenty-two eruptions were re-
corded in the seventeenth century, thirty-two in the eighteenth,
and in the few years that have elapsed of this present century
already eight. Catania, shaken and more or less injured at

• Extracted from A Tour in Italy and Sicili) in 1817- 1818. Lond. 1828.
P. 517, et seq.

+ Yet Virgil exhibits them in all their terrific grandeur to the Trojans
on their arrival in port.

. horrificis juxta tonat iEtna ruinis

Interdumque atram prorumpit ad aethera nubem,

Turbine fumantem piceo et candente favilla

AtoUitque globes flammarum et sidera lambit, &c.-~ ^n. iii. ^71.

Mr Simond on the Eruptions of Mount JEtna. 311

every one of these convulsions of ^tna, was completely over-
turned or burnt down, and its inhabitants wholly or in part
swallowed up, once in the twelfth century, and twice in the
seventeenth.*

But during the memorable earthquake of 1783, which shook
five hundred miles of country in a straight line through Sicily
and Calabria, spreading over all Italy and a great part of Eu-
rope a fixed haze, which for many months neither wind nor
rain could dispel, Catania suffered less in proportion than Mes-
sina. I have heard living witnesses describe the heaving up
and down of the earth during that memorable earthquake, as
resembling the motion of a carpet when the wind gets between
it and the floor, and as a sort of undulation producing sea-sick-
ness. The walls of buildings were not only thrown out of the
perpendicular, but so shaken as to lean different ways at the
same time, become totally disjointed, and fall to pieces. In
the sylvan region of ^Etna trees were seen bowing to one ano-
ther, and the phenomena was attended with tremendous inter-
nal noises — rimbombi e mugghiti, as the Italian language finely
expresses it, — and with occasional explosions as if the earth
were breaking open : in fact, it did break open in many parts of
Calabria, swallowing up villages and towns with all their inha-
bitants. The singular haze just mentioned might possibly
have issued from those openings ; meantime the great spiraglio
(loop-hole or vent-hole) of ^Etna (the crater at top,) remained
closed, — a fact which may serve to account for the violence of
the earthquakes.

It appears that more than one-third of these eruptions (fif-
teen out of forty-one,) took place in the months of February
and March ; a circumstance not unworthy of notice, for that
period of the year is just after the rains of January ; and it
may be inferred, that rain water penetrating into the heart of
the mountain, whence so very few springs are known to issue,
serves to kindle its fires. Yet rain on the upper regions of
JEtna is in winter always snow, and the rains on its base can
alone penetrate; thence we may conclude the local place of the
firewhichrain water has an agency in kindlingtobevery low down.

* The last time (1693), at the moment when the houses of Catania were
falling down and burying 18,000 people under their ruins, a tremendous
eruption put a stop to the earthquake which had lasted some days, and
was gradually increasing ; — the summit of the mountain fell in.

312 Contributions to Physical Geography.

It is a question here, whether the water of the sea also has
an agency in this great phenomenon. Many of the eruptions
have been attended with prodigious inundations down the sides
of ^tna : these floods Recupero and other writers maintain
to have been sea water thrown up by the volcano ; and as a
proof, it is alleged that shells have been deposited. But water
thus raised from the deep through a fiery channel would have
come out in the state of steam, and, instead of flowing down in
torrents along the earth, would have gone up into the air and
caused no inundation. The shells, too, calcined into lime and
immediately dissolved by the water, would have wholly disap-
peared before they reached the mouth of the volcano. These
great floods are very naturally explained by the melting of snow
upwards of ten feet deep before a stream of lava. The water
of the sea, though not thrown up, may still have an agency in
kindling the fires of the volcano ; and it certainly is a remark-
able circumstance, that most volcanoes are situated near the
sea or under it ; yet too much water would soon extinguish
the fire it had kindled, therefore the theory is in every way at-
tended with great difficulties. The height, often immense, at
which the craters of volcanos are found, is no argument
against the great depth of their burning recesses ; on the con-
trary, volcanic mountains being formed of ejected matters, their
height is the measure of that depth. The simultaneous earth-
quakes in Calabria and Sicily just before great eruptions of
^tna, and the simultaneous eruptions of that volcano and
Stromboli, scarcely leave any doubt of a communication exist-
ing under sea and land to Calabria, to the Lipari islands, and
very probably to Vesuvius or farther.

The greatest part of the coast south-west of ^Etna consists
of lava which in times long anterior to all historical records
ran down its sides. The dates of only two of the eruptions
which produced the lava are known, that of the 96th Olym-
piad, and another, 122 years before Christ. Recupero esti-
mates the quantity of volcanic matter ejected in the year 1669
alone (a memorable one indeed,) at ninety-four millions of
cubic passi^ (a passo is five feet,) equal to 11,750,000,000
cubic feet. Now that mass of solid matter would build nearly
a dozen such cities as London, supposing it to consist of

Mr Simond on the Eruptions of Mount uEtna. 313

208,000 houses, and each house to contain 5000 cubic feet of
walls. This same eruption of 1669 destroyed the habitations
of twenty-seven thousand people.

The region south of ^tna, extending towards Cape Pachi-
no nearly one hundred miles, exhibits often to a great depth
shelly calcareous strata alternating with what the Abbate Fer-
rara calls ancient lava, and the low grounds are full of marine
and argillaceous deposits. The base of the mountain, as far
as can be ascertained, is of the same nature. From all these
facts the same learned writer infers, that his ancient lava is of
submarine formation, the stupendous superstructure having
been reared after Sicily had become dry land. This ancient
lava, however, visible in many places, and particularly at La
Motta, very near the volcano, is in fact basalt ; a substance
which, although it resembles lava, and probably was likewise
once fluid through the agency of fire, differs too much, and
especially by its abundance, to have the same origin and be of
the same formation as lava.

Mtna, although situated nearly in the direction of the great
chain of the Appennines, stands insulated. It is a truncated
cone about ninety miles in circumference at the base and ten
miles at top, * where there it is a level plain round the mouth
of the volcano. That mouth in great eruptions occupies the
whole plain, while at other times it is no bigger than a man's
head, as I have heard it described here. Being the safety-
valve of the boiler, it cannot be quite closed without dreadful
consequences. In great eruptions there is certainly no possi-
bility of approaching to ascertain the state of the plain ten miles
in circumference just described ; but as it is afterwards found
to have undergone a total change, the cone upon it also being
rebuilt often in another place, there can be no doubt that du-
ring an eruption this lid of the boiling caldron comes off en-
tirely. When the activity of the fire begins to decline, the
lava instead of boiling quite over swells no higher than the
mouth of the crater, and there hardening quickly by its con-
tact with the open air, forms a leyel surface or new plain like

* ^tna being only 10,200 feet, or nearly two miles in height, while at
the base it is thirty miles in diameter, its ascent apparently steep is in re-
ality very gradual.

314 Contributions to Physical Geography.

that which before existed. A new cone is likewise soon formed
round the comparatively small opening which remains, and
through which stones and ashes are continually ejected. It
always assumes a regular form, sloping inside and outside at
an angle of about forty-five degrees. Its height at present is
1320 feet, its diameter at the base 2800 feet, the hollow in-
side 650 feet deep, and the inferior orifice there not more than
70 feet wide. At every great eruption this cone, which in En-
gland, in France, and over the greatest part of Europe, would
be looked upon as a very good- sized mountain, falls back again
into the fiery abyss from which it rose.

The total height of ^Etna, cone included, taking the me-
dium of various barometrical observations, and allowing a dif-
ference of 9$ inches of mercury (French measure) between the
sea-side and the top, is nearly 10,200 feet French measure.
The difference of temperature between these two extreme points
is about 40° of Fahrenheit. Although ^tna be fifteen or six-
teen hundred feet above the line of perpetual snows, in this
latitude (37° 51'), snow in summer is only found in a few
sheltered places ; especially in the great crater itself, where it
remains throughout the year. The whole country is supplied
with what is here deemed one of the necessaries of life from
this natural ice-house.

The whole of ^tna, as far as it can be ascertained, consists
of accumulated lava, scoriae, and ashes, the analysis of which
can alone throw some light on the nature of the substances
operated upon by the subterranean fires. It has often been
made ; and the substances found to predominate are, I believe,
silica and alumine*

2. Account of the Large Chestnut of Mount ^tna. By L.

SiMOND.*

liCaving the lettiga and baggage to follow the direct road
or path to La Nunziata, we went on horseback with a guide
over the mountain to see the celebrated chestnut-tree, called
Castagno di Cento Cavalli, because 100 horses might stand
together under its shade. We rode ten hours for that pur-
pose over rugged tracts of lava and precipices, requiring the
* From Tour in Halt/ and Skill/. Lond. 1828. Pp. 310, 513.

Mr Siinond on the Large Chestnut of' Mount jEtna. 315

singular prudence and sure-footedness of our cattle to get
through without accident. On the way we had occasion to ob-
serve melancholy traces of the earthquake of February last,
particularly at the village of Zafarana, where the falling of
the arched roof of the church crushed the curate and forty-one
of his parishioners, only nine of whom were extricated alive ;
not a woman among the sufferers, for they had attended church
in the morning, and the evening service had been performed
on purpose for the men who had been out at work during the
whole of that day. We saw a parcel of children playing with
great glee among the ruins, and observed young women be-
comingly adjusting their black veils to please the living, al-
ready unmindful of the dead.

The lava of the great eruption of the first year of the 96th
Olympiad, which formed the promontory of Aci in the sea, is
still bare of soil, and without vegetation in many places, while
that of 1669 is already covered with vines and fruit trees.
The fact is, that compact lava is scarcely more liable to decom-
position than any hard rock, and that scoriae only are liable to
decomposition ; the lava of 1669 probably abounded with sco-
riae. The promontory of Aci above mentioned, is 900 feet
high, but far from being all formed by the lava of one erup-
tion ; the traces of as many as nine are observed one over the
other, with argillaceous earth intervening.

The astonishing fertility of the soil all over the base of
JEtna^ and the luxuriant growth of all the plants, prepared us
in some sort for the miracle of vegetation which we were about
to behold ; and when the Castagvto di Cento Cavalli actually
appeared before us, it seemed to make no very great figure, but
on near inspection we were truly amazed.

Recupero says that he had the ground dug all round, and
found a continuity of roots and even bark.

The present appearance is certainly that of a group of five
large trees, one only of which is sound and covered with bark
all round, while the others are decayed on the inward side,
each of them appearing to be sections of a circumference small-
er than the great one of 112 feet, which they all five with
their intervals form together. Taken outside the bulging roots,
that circumference might be reckoned at 180. The limbs, al-

316 Contributions to Physical Geography.

though vigorous and of great size, had lost their extremities,
and upon the whole the mass of foliage bore no proportion to
the stem or stems. This was not the only giant of the same
family ; for at the distance of 400 yards we saw two other
chestnut- trees of vast size, and of greater beauty than the Cen-
to CavallL One of them, consisting of two stems in close con-
tact and from the same root, measured 24 feet in diameter,
and was quite sound ; the other measured 15 feet in diameter,
but was entirely hollow, and presented within tlie singular ap-
pearance of several young stems, five or six inches in diame-
ter, joining at top the hollow trunk, and looking like stalac-
tites in a cavern. Probably when the inside of the tree, whol-
ly decayed, had become vegetable earth, roots shot into it and
down into the ground below ; but in process of time that earth
was washed away, and these internal roots exposed to the air,
became so many stems, and ultimately young trees within the
old one. Half a mile from these stood a fourth chestnut-tree,
shattered above, but its stem quite sound, and that stem up-
wards of 70 feet in circumference. The soil in which all these
trees grew was of a dark reddish brown or chocolate colour,
very loose and penetrable. The fruit of the Cento Cavalli is
rather smaller, and otherwise not quite so good as that of the
other trees. This region of vegetable wonders is no less than
4000 feet above the sea.

3. Account of the Falls of Niagara.

" I had already seen some of the most celebrated works of na-
ture in different parts of the globe; I had seen iEtna and Vesuvi-
us; I had seen the Andes almost at their greatest elevation ; Cape
Horn, rugged and bleak, buffeted by the southern tempest ;
and, though last not least, I had seen the long swell of the
Pacific ; but nothing I had ever beheld or imagined could
compare in grandeur with the falls of Niagara, My first sensa-
tion was that of exquisite delight at having before me the
greatest wonder of the world. Strange as it may appear, this
feeling was immediately succeeded by an irresistible melan-
choly. Had this not continued, it might perhaps have been
attributed to the satiety incident to the complete gratification
of ' hope long deferred ;' but so far from diminishing, the

Account of the Falls of Niagara. 317

more I gazed, the stronger and deeper the sentiment became.
Yet this scene of sadness was strangely mingled with a kind of
intoxicating fascination. Whether the phenomenon is pecu-
liar to Niagara, I know not, but certain it is, that the spirits
are affected and depressed in a singular manner by the magic
influence of this stupendous and eternal fall. About five miles
above the cataract the river expands to the dimensions of a
lake, after which it gradually narrows. The Rapids com-
mence at the upper extremity of Goat Island, which is half a
mile in length, and divides the river at the point of precipita-
tion into two unequal parts ; the largest is distinguished by
the several names of the Horseshoe, Crescent, and British Fall,
from its semicircular form and contiguity to the Canadian
shore. The smaller is named the American Fall. A portion
of this fall is divided by a rock from Goat Island, and though
here insignificant in appearance, would rank high among Eu-
ropean cascades.

" The current runs about six miles an hour ; but suppos-
ing it to be only five miles, the quantity which passes the falls
in an hour is more than 85,000,000 tons avoirdupois ; if we
suppose it to be six, it will be more than 102,000,000; and
in a day would exceed 2,400,000,000 tons.

" The next morning, with renewed delight, I beheld from
my window the stupendous vision. The beams of the rising
sun shed over it a variety of tints ; a cloud of spray was as-
cending from the crescent ; and as I viewed it from above,
it appeared like the steam rising from the boiler of some mon-
strous engine. *****

*' This evening I went down with one of our party to view
the cataract by moonlight. I took my favourite seat on the
projecting rock, at a little distance from the brink of the fall,
and gazed till every sense seemed absorbed in contemplation.
Although the shades of the night increased the sublimity of
the prospect, and ' deepened the murmur of the falling floods,'
the moon in placid beauty shed her soft influence upon the
jcnind, and mitigated the horrors of the scene. The thunders
which bellowed from the abyss, and the loveliness of the fall-
ing element, which glittered like molten silver in the moon-

318 ContHbutions to Physical Geography.

light, seemed to complete the rare union of the beautiful with
the sublime. * * # *

" Though earnestly dissuaded from the undertaking, I de-
termined to employ the first fine morning in visiting the cavern
beneath the fall. The guide recommended my companion and
myself to set out as early as six o^clock, that we might have
the advantage of the morning sun upon the waters. We came
to the guide's house at the appointed hour, and disencumbered
ourselves of such garments as we did not care to have wetted.
Descending the circular ladder, we followed the course of the
path running along the top of the debris of the precipice,
which I have already described. Having pursued this tract
for abouty eighty yards, in the course of which we were com-
pletely drenched, we found ourselves close to the cataract.
Although enveloped in a cloud of spray, we could distinguish
without difficulty the direction of our path and the nature of
the cavern we were about to enter. Our guide warned us of
the difficulty in respiration which we should encounter from
the spray, and recommended us to look with exclusive atten-
tion to the security of our footing. Thus warned, we pushed
forward, blown about and buffeted by the wind, stunned by
the noise, and blinded by the spray ; each successive gust pene-
trated us to the very bones with cold. Determined to proceed,
we toiled and struggled on, and having followed the footsteps
of the guide as far as was possible, consistently with safety, we
sat down, and having collected our senses by degrees, the
wonders of the cavern slowly developed themselves. It is im-
possible to describe the strange unnatural light reflected
through its crystal wall, the roar of the waters, and the blasts
of the hurricane, which perpetually rages in its recesses. We
endured its fury a sufficient time to form a notion of the shape
and dimensions of this dreadful place. The cavern was toler-
ably light, though the sun was unfortunately enveloped in
clouds ; his disc was invisible, but we could clearly distinguish
his situation through the watery barrier. The fall of the cata-
ract is nearly perpendicular ; the bank, over which it is preci-
pitated, is of concave form, owing to its upper stratum being
composed of limestone and its base of soft slatestone, which has
been eaten away by the constant attrition of the recoiling wa-

Accmmt of a Storm in the Desert. S19

ters. The cavern is about one hundred and twenty feet in
height, fifty in breadth, and three hundred in length ; the en-
trance was completely invisible. By screaming in our ears,
the guide contrived to explain to us that there was one more
point which we might have reached had the wind been in any
other direction ; unluckily it blew full upon the sheet of the
cataract, and drove it in, so as to dash upon the rock over
which we must have passed. A few yards beyond this, the
precipice becomes perpendicular, and blending with the water,
forms the extremity of the cave. After a stay of nearly ten
minutes in this most horrible purgatory, we gladly left it to it^
loathsome inhabitants, the eel and the water-snake, who crawl
about its recesses in considerable numbers, and returned to
the inn." — De Rods' Personal Narrative.

4. Account of a Storm in the Desert.

Suez, February 23, 1814.

After having travelled all the morning in the bed of the
ancient canal that formerly connected the Red Sea with the
Mediterranean, but without being able to discover a vestige of
anything like masonry, or indication of the sluices by which
its waters were said to have been regulated, we had lost, at
noon, all traces of its course, though we continued our direc-
tion still northerly, inclining two or three points to the west,
until we gained the site of the Bitter Lakes, as they were call-
ed by the ancients, and named the Salt Marshes in more mo-
dern maps. We traversed it in every direction, however, for
a diameter of ten miles, having fleet trotting dromedaries be-
neath us, without finding the least portion of water, although
it had evidently been the receptacle of an extensive lake, and
was at this moment below the level of the sea at Suez. The
soil here diff'ers from all around it.

On leaving the last traces of the canal, we had entered upon
a loose shifting sand ; here we found a firm clay mixed with
gravel, and perfectly dry, its surface encrusted over with a
strong salt. On leaving the site of these now evaporated lakes,
we entered upon a loose and shifting sand again, like that
which Pliny describes when speaking of the roads from Pe-
lusium across the sands of the desert ; in which, he says, unless

320 Contributions to Physical Geography.

there be reeds stuck in the ground to point out the line of di-
rection, the way could not be found, because the wind blows
up the sand, and covers the footsteps.

The morning was delightful on our setting out, and pro-
iri^sed us a fine day ; but the light airs from the south soon in-
creased to a gale, the sun became obscure, and as every hour
brought us into a looser sand, it flew around us in such whirl-
winds, with the sudden gusts that blew, that it was impossi-
ble to proceed. — We halted, therefore, for an hour, and took
shelter under the lee of our beasts, who were themselves so
terrified as to need fastening by the knees, and uttered, in
their wailings, but a melancholy symphony.

I know not whether it was the novelty of the situation that
gave it additional horrors, or whether the habit of magnifying
evils to which we are unaccustomed, had increased its effect ;
but certain it is, that fifty gales of wind at sea appeared to me
more easy to be encountered than one amongst those sands.
It is impossible to imagine desolation more complete ; we could
see neither sun, earth, or sky ; the plain at ten paces distance
was absolutely imperceptible ; our beasts, as well as ourselves,
were so covered as to render breathing difficult ; they hid their
faces in the ground, and we could only uncover our own for a
moment, to behold this chaos or mid-day darkness, and wait
impatiently for its abatement. Alexander's journey to the
temple of Jupiter Ammon, and the destruction of the Persian
armies of Cambyses in the Lybian Desert, rose to my recollec-
tion with new impressions, made by the horror of the scene be-
fore me ; while Addison's admirable lines, which I also re-
membered with peculiar force on this occasion, seemed to pos-
sess as much truth as beauty : —

Lo ! where our wide Numidian wastes extend,
Sudden the impetuous hurricanes descend.
Which through the air in circHng eddies play.
Tear up the sands, and sweep whole plains away.
The helpless traveller, with wild surprise.
Sees the dry desert all around him rise :
And, smothered in the dusky whirlwind, dies.

The few hours we remained in this situation were passed in
unbroken silence ; every one was occupied with his own re-

B^crning Sprbigs in America. 321

flections, as if the reign of terror forbade communication. Its
fury spent itself, like the storms of ocean, in sudden lulls
and squalls ; but it was not until the third or fourth interval
that our fears were sufficiently conquered to address each
other ; nor shall I soon lose the recollection of the impressive
manner in which that was done. " Allah kereem V^ exclaimed the
poor Bedouin, although habit had familiarized him with these
resistless blasts. " Allah kereem !" repeated the Egyptians,
with terrified solemnity ; and both my servant and myself, as
if by instinct, joined in the general exclamation. The bold
imagery of the Eastern poets describing the Deity as aveng-
ing in his anger, and terrible in his wrath, riding upon the
wings of the wind, and breathing his fury in the storm, must
have been inspired by scenes like these.

It was now past sunset, and neither of us had yet broken
our fast for the day ; even the consoling pipe could not be
lighted in the hurricane ; and it was in vain to think of re-
maining in our present station, while the hope of finding some
bush for shelter remained. We remounted, therefore, and de-
parted. The young moon afforded us only a faint light, and all
traces of the common road were completely obliterated ; the
stars were not even visible through so disturbed an atmo-
sphere, and my compass was our only guide. The Arabs knew
a spot near Sheick Amidid, where banks and trees were to be
found, and, confiding in my direction for the course thither, we
resumed our journey.

After a silent ride of five tedious hours, this garden of re-
pose appeared in sight ; and bleak and barren as it was, in
truth, fatigue and apprehension gave it the charms of Eden.
There we alighted, fed our weary animals, and, like sailors
escaped from shipwreck, regaled in that delightful conscious-
ness of security which is known only in the safety which suc-
ceeds to danger. — Buckingham'' s Journal.

5. Burning Springs in America *.

Springs of water charged with inflammable gas are quite
common in the vicinity of Canandaigua, the capital of Ontario
county, in the south-western part of the State of New York

"f»0O'> m * See this Journal, No. xv- p. 183.

VOL. X NO. II. APKIL 1829. X

322 Contributions to Physical Geography.

Those at Bristol, ten miles S. W. of Canandaigua, are situat-
ed in a ravine on the west side of Bristol Hollow, about half
a mile from the north Presbyterian Meeting-house. The ra-
vine is formed in clay-slate, and a small brook runs throuo-h
it. The gas rises through fissures of the slate from both the
margin and bed of the brook. Where it rises through the
water it is formed into bubbles, and flashes only when flame
is applied; but where it rises directly from the rock, it burns
with a steady and beautiful flame, which continues until ex-
tinguished by storms or by design.

The springs of Middlesex (twelve miles south from Canan-
daigua,) are from one to two miles south-west of the village of
Rushville, along a tract nearly a mile in length, partly at the
bottom of the valley called Federal Hollow, and partly at an
elevation of forty or fifty feet on the south side of it.

These latter springs have been discovered within a few years,
in a field which had long been cleared, and are very numerous.
Their places are known by little hillocks a few feet in diame-
ter and a few inches high, formed of a dark bituminous mould,
which seems principally to have been deposited by the gas,
and through which it finds its way to the surface in one or
more currents. These currents of gas may be set on fire, and
will burn with a steady flame. — In winter they form openings
through the snow, and being set on fire, exhibit the novel and
interesting phenomenon of a steady and lively flame in contact
with nothing but snow. In very cold weather, it is said, tubes
of ice are formed round these currents of gas (probably from
the freezing of the water contained in it) which sometimes rises
to the height of two or three feet, the gas issuing from the
tops ; the whole, when lighted in a still evening, presenting
an appearance even more beautiful than the former.

Some time since, the proprietors of this field put into opera-
tion a plan for applying the gas to economical purposes. From
a pit which was sunk in one of the hillocks, the gas is con-
ducted through bored logs, to the kitchen of the dwelling, and
rises through an aperture, a little more than half an inch in
diameter in the door of a cooking stove. When inflamed, the
mixture of gas and common air in the stove first explodes, and
then the stream burns steadily. The heat evolved is consi-

Meteorological Register kept at Kinfauns Castle. 323

derable ; so that even this small supply is said to be sufficient
for cooking. In another part of the room a stream of the gas,
from an orifice one-eighth of an inch in diameter, is kindled in
the evening, and affords a light equal to three or four candles.
The novelty of the spectacle attracts a concourse of visitors so
great, that the proprietors have found it expedient to convert
their dwelling into a public inn.

Art. XIX. — Meteorological Register for 1828, Icept at Kin-
fauns Castle^ the seat of the Right Honourable Lord Gray.

Kinfauns Castle is situated in N. Lat. 56° 23' 30", and 1 40
feet above the level of the sea.

1828.

Morning, -| past 9.
Mean height of

Evening, i past 8.
Mean height of

Barom.

Ther.

Barom.

Ther.

January,

29674

41.258

29.700

40.968

February,

29.561

41.104

29.583

40.517

March,

29.645

44.774

29.629

43.484

April,

29.534

44.600

29.525

45.443

May,

29.696

55.S55

29.691

50.968

June,

29.715

61.000

29.739

57.000

July,

29.499

62.710

29.505

58.967

August,

29.600

60.355

29.601

58.000

September,

29.732

57.267

29.736

55.167

October,

29.789

50.226

29.807

48.258

November,

29.615

46.433

29.606

45.533

December,

29.529

45.226

29.543

44.806

verage of year

, 29.632

50.859

29.639

49.093

Mean
Temp, by
Six's.
Ther.

Depth of
Rain in
Garclen.

Number

of days.

Rain

snow.

Fair.

January,

41.613

3.40

February,

41.414

3.30

March,

44.355

1.00

April,

44.06

2.80

324 Meteorological Register kept at Kiii/auns Castle.

May,

53.000

2.75

June,

68.567

1.90

July,

60.549

2.50

August,

59.710

4.50

September,

56.200

1.50

October,

49.613

2.00

November,

46.400

5.00

December,

44.806

3.00

Average of year, 50.219 33.65 148 218

Annual Results.
Morning.

Barometer. Thermometer.

Observations. Wind. Wind.

Highest, 29th Oct. S. W. 30.44 25th June, S. W, 69°

Lowest, 21st March, W. 28.59 18th February, S. W. 30°

Evening.

Highest, 28th Oct. S. W. 30.48 22d June, S. W. - 69°
Lowest, 21st March, W. 28.70 10th January, N. E. 28°

Weather

Days.

Wind.

Times.

Fair,

218

N. and N. E.

Rain or Snow,

148

E. and S. E.

S. and S. W.

146

366

W. and N. W.

. 83

366
Extreme cold and heat by Six's Thermometer.

Coldest, 11th January, - Wind, N. W. 22
Hottest, 29th June, - do. S. W. 78°

Mean Temperature for the year 1828, 50°219

Results of 2 Rain Guages. In. 100

1. Centre of Kinfauns Garden, about 20

feet above the level of the sea, - 33.65

2. Square Tower, Kinfauns Castle, 140 feet, 34.40

Dr Brewster 07i a peculiarity in Glauberite. 325

Art. XX. — Account of a remarkable peculiarity in the Struc-
ture of Glauberite,* which has One Axis of Double Refrac-
tion fur Violet, and Two Axes for Red Light. By David
Brewster, LL. D. F. R. S. L. & E.

In the optical and mineralogical classification of crystals which
I published in the article Optics in the Edinburgh Encyclo-
pcedia, I have arranged Glauberite among those which have
two axes of double refraction. The fragment which I used
however, was so small and imperfect, that I could not measure
the inclination of the resultant axes, or ascertain with any ac-
curacy its action upon light. Mr William Nicol, Lecturer on
Natural Philosophy, &c. and whose ingenuity is already well
known, put into my hands two specimens of Glauberite, which
he had skilfully prepared for showing its double system of
polarised rings ; and, by the use of these, I have been enabled
to detect a very remarkable property in this mineral.

When examined by common polarised light, the tints of its
rings are exceedingly anomalous, and we seek in vain for the
two poles where the double refraction and polarisation gene-
rally disappear. The cause of this irregularity immediately
shows itself, when we expose the crystal to homogeneous rays.
In the Red rays, we observe the phenomena of two distinct
axes, the inclination of the resultant axes being about 5°.
This inclination gradually diminishes in the orange, yellow,
and green rays, and in the violet the two poles coincide, ex-
hibiting the system of rings round a single axis of double re-
fraction. In all these cases, the character of the principal axis
is negative.

When Mr Herschel discovered the very remarkable property
in a specimen of Apophyllile, in virtue of which it exercised a ne-
gative influence over the red rays, a positive influence over the
blue rays, and no influence at all over the yellow ones, I showed
in a paper read before this Society, and printed in their Transac-
twns,\ that these apparently irreconcileable actions, related, as

• Abridged from the original paper read to the Royal Society of Edin-
burgh, Januaiy 9th, 1828, and which will appear in the Transactions,
vol. xi. part ii. now in the press. — Ed«

t Edinburgh Transactions, vol. ix. p. 317.

326 Dr Brewster on a peculiarity in Glauberiie,

they seemed to be, to a single axis of double refraction, could
be calculated in the most rigorous manner, by supposing the
crystal to have three positive axes at right angles to each other,
each of which exercises a different dispersive action upon the
differently coloured rays. This result, which is of considerable
importance in the theory of double refraction, is strikingly
confirmed by the phenomena of Glauberite, while these at the
same time present us with a new and still less equivocal case of
the composition of axes.

In the case of Glauberite, observation exhibits to us one ne-
gative axis A, which is the single axis for the violet light, and
the principal axis for the red and the other less refrangible
rays; and, at the same time, it presents to us a second axis B,
which may be either negative or positive , but which must be
90° distant from A. If it is negative, it must be in a plane
perpendicular to the plane passing through the two resultant
axes for red light ; and it must bear to A the ratio of the
square of the sine of 2|° (half the inclination of the resultant
axes) to unity. * If it is positive, it must lie in the plane pas-
sing through the resultant axes, and it must bear to A the
ratio of the square of the sine, to the square of the cosine of
2J°. But whether it be positive or negative, it exercises no
action whatever upon violet light, a supposition so absurd,
that it cannot for a moment be received. Since the combina-
tion of axes, therefore, indicated by experiment for the
single system of rings in violet light, and for the double
system in the other rays, involves a physical absurdity, we
must seek for a new combination, not liable to such an ob-
jection.

If we suppose that the axis A for violet light is the result-
ant of other axes, and that these other axes are two positive
axes B and C at right angles to each other, and also to the ap-
parent axis A, we shall obtain an explanation of all the pheno-
mena. If the axes B, C, exercise the same action on the violet
rays, they will produce a single negative axis at A for violet
light, as given by observation ; and if the relative intensities
of their action upon red light are in the ratio of the square of

• See VhHos<>]>hical Transactions, 1818, p. 237, &c.

Mr Pritcliartrs Single Lem Microscopes. '527

the cosine of 2J° to unity, the intensity of the weakest gradually
diminishing to zero for the rays between the red and the violet,
then we can calculate, with mathematical precision, all the
phenomena of doul)le refraction and polarisation exhibited by
Glauberite.

The structure of Apophyllite and Glauberite, therefore, fur-
nish vf& with two unequivocal examples of minerals where the
real axes of double refraction are not pointed out by observa-
tion. Their crystallographic structure does not indicate.^ with,
any certainty, the locality of the axes which we l^aye now in^
ferred from the laws of double refraction ; but we have no
doubt that the results of crystallography and optical structure
will ultimately coincide, when our knowledge of the primitive
and secondary forms of minerals shall have attained a higher
degree of perfection.

Art. XXI. — Account of' the Single Lens Microscopes of' Sap-
phire and Diamond, executed by Mr A, Fritchard, Opti-
cian, London.

Although very successful attempts have been recently made
in foreign countries to improve the microscope, particularly by
Professor Amici of Modena, yet, notwithstanding %he absolute
discouragement of every species of science, whether theoretical
or practical, this invaluable instrument has, in this country,
undergone the most important improvements. For this great
step in practical optics, England has been mainly indebted to
the unwearied exertions of Dr Goring and Mr Pritchard.

With a liberality which nothing but the most ardent love of
science would have prompted, and which was fortunately di-
rected by optical knowledge, Dr Goring devoted his time and
his fortune to the improvement of the microscope in all its
forms. He was not content with speculative suggestions and
improvements. He submitted every idea to the test of direct
, experiment, and was thus enabled to give to his contrivances
that practical value, which is so often wanting in the inventions of
theoretical men. We hope to be able to lay before our readers
some account of the successive labours of Dr Goring, in tlie
New Series of this Journal, which commences with the next

328 Account of Mr Pritchard's Single Lens Microscopes

Number. In the meantime, we shall proceed to give an ac-
count of the single microscopes of sapphire and diamond, which
have been so successfully executed by Mr Pritchard.

In the years 1810 and 1811, when Dr Brewster had deter-
mined the refractive and dispersive power of the gems, and
found that some of them united very low dispersive with very
high refractive powers, he pointed out the advantages of such
an union of optical properties, for the construction of single mi-
croscopes. About ten years ago, Mr Peter Hill, an ingenious
optician in Edinburgh, executed for him two single lenses of
rubi/ and garnet, which were used both as single microscopes,
and as the object-glasses of a compound microscope. Mr Siv-
right of Meggetland had also executed for him, we believe by the
same artist, a single piano convex lens, of the colourless topaz
of New Holland. Such were the attempts which had been made
previous to the labours of Mr Pritchard, who has given the
following account of them in the Treatise on Optical Instru-
ments, published by the Society for the diffusion of Knowledge.

" Dr Brewster, in his Treatise on New Philosophical Instru-
ments, speaking of single microscopes, says, — ' We cannot
expect any essential improvement in that instrument, unless
from the discovery of some transparent substance, which, like
the diamond, combines a high refractive power with a low
power of dispersion.' This substance has subsequently been
formed into lenses by Mr A. Pritchard, at the suggestion of
Dr Goring, who caused Mr P. to commence the undertaking
in June 1824. The first diamond lens was completed at the
end of that year. The difficulty of working this substance
into a perfect figure was subsequently overcome. Mr Pritchard
finished the first diamond microscope in 1826; the focal dis-
tance of this magnifier, which is double convex, is about j^o^^
of an inch. Of the value and importance of the introduction
of this brilliant substance for the formation of single micro-
scopes, Dr Goring states, " I conceive diamond lenses to consti-
tute the ultimatum of perfection in the single microscope.

*' The principal advantages of employing this brilliant sub-
stance in the formation of microscopes, arise from the natural-
ly high refractive power it possesses, whereby we can obtain
lenses of any degree of magnifying power, and that with com-

of Sapphire and Diamond. 329

paratively shallow curves ; the indistinctness occasioned by the
figure of the lens is thus greatly diminished, and the disper-
sion of colour in the substance being as low as that of water,
renders the lens nearly achromatic."

The advantages arising from diamond, sapphire, and ruby
lenses, will be at once seen from the following measures of
their refractive powers, as established by Dr Brewster : —

Index of refraction. Dispersive power.

Diamond, 2.470 0.38

Sapphire, 1.780 0.26

Ruby, 1.779 0.26

Plate glass, 1.525 0.32

In this table the superiority of the diamond is very obvious ;
while it produces, in virtue of its low dispersive power, very
little colour, its enormous refractive index enables the artist
to produce a high magnifying power with very shallow curves.

The sapphire and the ruby, though they have not the same
advantage as the diamond in giving the same magnifying
power with as shallow curves, yet they have another valuable
property in greater perfection than the diamond, namely, a
very low dispersive power.

On the other hand, the diamond has again the superiority
over the sapphire and ruby lenses by its generally having no
double refraction, whereas the former have a considerable
double refraction ; and we presume Mr Pritchard found it ab-
solutely necessary to make the axis of his sapphire lenses co-
incident with their axis of double refraction, which is parallel
to the axis of the acute rhomboid in which these gems crystal-
lize. But even if this is effected, the transmitted rays cannot
all pass through the lens parallel to its axis, so that they must
to a certain minute degree be separated into two pencils ; but
to what extent this will affect the performance of the lens as a
microscope we do not yet know.

But though the diamond may be said to have no double re-
fraction when perfectly crystaUized, yet, in nine cases out of
ten, Dr Brewster has discovered in it a doubly refracting
structure. (See Edinburgh Transactions, vol. viii. p. 157, and
Edinburgh Philosophical Journal, vol. iii. p. 98.) Mr Pritchard

330 Account of Mr Prilchard's Single Lens Microscopes

indeed has himself found some of the diamond lenses which
he made, quite defective, giving something like a treble image.
Hence it would be adviseable to manufacture diamond lenses
only out of plates of diamond, through which it is easy to ex-
amine by polarized light its doubly refracting structure,
and to reject all the plates in which there is the slightest ten-
dency to this structure. If the diamond has not sufficiently
flat surfaces to admit of this experiment being easily made, it
should be examined when immersed in oil of cassia or sulphu-
ret of carbon, — the fluids which approach nearest to it in re-
fractive power.

Mr Pritchard mentions, that he has also "• formed lenses of
the other precious stones, but without any peculiar advantage,
many of them producing two magnified images by double
refraction." Zircon^ Essonite, JEuclase, and some others,
would no doubt produce this effect to a great degree ; but
Garnet, Pyrope, Spinelle, and Rub?/ will not give double
images. We have examined specimens of garnet, &c. so per-
fectly pure, that we would recommend strongly to Mr Prit-
chard to devote his attention to this substance. Its refrac-
tive index is 1.815 greater than that of sapphire, while its
power of dispersion is 0.33 inferior to 'diamond, so that, from
its having no double refraction, it unites the theoretical requi-
sites for a perfect microscope in a greater degree than either
diamond or sapphire. As the observation of colour is the
least of all considerations, and is besides a very fallacious one
in microscopic observations, the colour of the garnet cannot
be regarded as a disadvantage. It is on the contrary an ad-
vantage, as it renders the microscope more achromatic by its
absorption of the violet or most refrangible rays. But even
if the observation of colour were material, we can determine
it as clearly by a coloured as by a colourless lens. If, for ex-
ample, the garnet lens shows an object or part of an object of
a certain apparent colour, it is easy to determine the real co-
lour by ascertaining what colour seen through the lens pro-
duces the apparent colour under consideration.

As it is now perfectly easy to illuminate microscopic ob-
jects with homogeneous light, we may set aside all considera-
tion of the dispersive power of bodies, and employ for single

(,f S(tpphire and Diamond. 331

lenses all substances that have a high refractive power, and no
double refraction. Substances of this kind which are suitable
for such a purpose, are

Index of Refraction.
Realgar, - 2.549

Blende, - 2.260

Glass of Antimony, 2.216 for red rays.

Glass of antimony will no doubt take a good polish. Blende
will probably do the same; but^ealgar is perhaps too soft. Real-
gar is capable, however, of being melted, and we have no doubt
that small transparent lenses of it could be moulded between
small polished concave surfaces. We formed in this way a
prism which enabled us to obtain a tolerably good measure of
its refractive and dispersive power ; so that there appears to
be no practical difficulty in moulding it into very minute
lenses. The realgar will retain its lustre, as we know by the
prism now mentioned, which we have kept for sixteen years.

As the power of homogeneous illumination renders achro-
matic combinations of little use in microscopic observations,
the perfection of the single microscope must depend on the
degree to which we are able to remove the spherical aberra-
tion.' Hence the radii of the single lenses should be as 6 to 1,
and when they are of sufficient size, some of the contrivances
for a diaphragm within the lens should be adopted.

Although we are not yet able to speak from our own ob-
servation of the excellence of Mr Pritchard's lenses, yet we
are in possession of the most satisfactory evidence of their im-
mense superiority to all single microscopes hitherto made, and of
their equality to the most expensiye Amician and achromatic
instruments. Mr Pond, our able astronomer-royal, having pro-
cured one of Dr Goring's improved Amician microscopes, with
metals of only six-tenths of an inch focu^, and three-tenths of
clear aperture, was desirous of comparing it with one of Mr
Pritchard's sapphire lenses. He accordingly selected a plane
convex sapphire lens of ^^jth of an inch in focal length, and he
found that, in every case, it exhibited all the most delicate test
objects that could be seen with the reflecting microscope, and
was otherwise equal to it in its performance. Since this com-

332 Acccmnt of Mr Pritchard's Smgle Lens Microscopes

parison was made, Mr Pond has had two aplanatic micro-
scopes made for him, the one by Mr TuUey, and the other by
Mr Dollond, with double triple object-glasses, and both of
these fine instruments, executed by the first artists in Europe,
are equalled by the simple sapphire lens.

Our late distinguished countryman Dr Wollaston likewise
compared the sapphire lens with these three instruments at
the Royal Observatory. He also was perfectly satisfied that
it was equal to these fine instruments ; and he immediately
ordered for his own use a set of the sapphire lenses.

Now since these three instruments with which the simple
sapphire lens has been compared have no aberration of
refrangibility, the reflecting microscope having necessarily
none, and the other two having it completely corrected, while
the sapphire lens has the disadvantage of all its uncorrected
colour, and yet ecjuals them, it is manifest that the sapphire
lens must surpass them completely/, when it is put on the same
footing 171 point of refrangibility, that is, when the objects are
illuminated with homogeneous light.

We would, therefore, strongly recommend it to Mr Pritchard,
to turn his attention to the simplest method of obtaining ho-
mogeneous light, and to have the apparatus made to accompany
his lenses. For opaque objects, coloured silks and paper produce
a very fine effect, and from the vegetable world the most per-
fect homogeneous light may be obtained. In another paper
we shall give an account of a series of experiments, which we
have made on this subject with the flowers and leaves of
plants in different stages of their growth ; but we may men-
tion, in the meantime, that the petals of the scarlet lychnis re-
flects at a certain stage of its growth a pure homogeneous red,
upon which opaque objects are most beautifully seen.

There are two advantages of the diamond and sapphire lenses
which we must not omit to mention. From their great hard-
ness, they will never be scratched or injured by use like those
made of glass ; and from the same cause, the artist is enabled
to burnish them into small flat plates of brass, which prevents
the possibility of their being lost, and renders them capable of
being cleaned without danger.

As Mr Pritchard is now executing for us one of his sap-

of Sapphire and Diamond. 333

phire microscopes for the purpose of determining some delicate
points in the structure of minerals, in which all our usual re-
sources have failed, we hope to be soon able to speak of them
from personal observation ; but with such evidence in their fa-
vour as that of Dr Goring, Mr Pond, and L)r Wollaston, no
farther recommendation is necessary ; and we look forward
with sanguine expectation to the discoveries which it will en-
able the naturalist to make respecting the structure and func-
tions of organic bodies.

The perseverance and skill of Mr Pritchard in executing
lenses of such refractory materials is beyond all praise, and we
must make some demand upon the faith of our readers when
we inform them that he can execute diamond lenses the one
hundredth part of an inch in focal length. Such exertions and
such success would, in other countries, have obtained the pa-
tronage of sovereigns, and the countenance of government ;
but England does not thus honour her scientific artists, and we
therefore anxiously hope, that the great merits of Mr Pritchard
will not be overlooked by that individual patronage which
may still, for a brief period, preserve from exile the declining
arts of our country.

We have been fortunate in obtaining the following list of
prices at which Mr Pritchard is able to dispose of his sapphire
and diamond lenses : —

Focal length of sapphire lenses.
From 1-lOth to l-30th of an inch, L. % 2s.
From l-30th to l-60th of an inch, L. 3, 3s.
From l-60th to l-80th of an inch, L. 4, 4s.
From l-80th to 1-lOOdth of an inch, L. 5, 5s.
Diamond lenses cost from ten to twenty guineas each.

We are glad to find, that Dr Goring and Mr Pritchard
have published the First Number of a Work on the Micro-
scope and its Objects, entitled " The Natural History of seve-
ral new living objects for the Microscope ^ conjoined with accu-
rate descriptions of the Diamond, Sapphire, Aplanatic, and
Amician Microscopes, ^c. ^^c." It is to be had of Mr Pritch-
ard, 18 Picket Street, Strand, London, and we may perhaps
be able to lay before our readers some account of it in a sub-
sequent article of this number.

834) Mr Forbes on the Defects of the Sympiesometer,

Art. XXII. — On the Defects of the Sympiesometer, as applied
to the Measurement of Heights. By James D. Forbes, Esq.
Communicated by the Author.

The Sympiesometer is an instrument more attractive at first,
perhaps, than in longer experience, and in its capabihty for ex-
pressing rather than receiving minute impressions. This will
account in some measure for the very partial adoption of a
contrivance, the excellency of the theory, and the ingenuity
of the inventor of which all will admit. The principle indeed
is by no means new, having been discussed by Hooke and
others in the earlier Philosophical Transactions ; but Mr Adie
has given it an elegance and an accuracy which its older pro-
jectors never aniicipated. ,

The portable sympiesometer, notwithstanding its lightness^
is not likely often to replace the barometer in the hands either
of the practical man or the refined philosopher ; and briefly
for these reasons : It is as expensive and even more so than
a plain mountain barometer. Though not nearly so liable to
break as the mercurial tube by concussions, these will readily
separate the oil, and sometimes render the instrument equally
useless for the time, till it has undergone a rather hazardous ope-
ration. It must be kept in one position only, — a material objec-
tion, whereas a proper barometer maybe travelled in any posi-
tion. Though the space corresponding to an inch of mercury
is far greater, the viscidity of the oil is so considerable, that it
is impossible to read off* the height to less than t Jo of an inch,
and it is much to be doubted if the level of the oil be true to
that quantity. A barometer of similar expence will be read off"
with secure accuracy to one-fifth of that space. Any barome-
ter tolerably constructed will take its level in half a minute, but
the sympiesometer will not merely require for the same pur-
pose four or five minutes, as the inventor in his pamphlet states,
but I mean to show that the time thus required may be actUr-
ally indejinite, and to explain some weighty objections con-
nected with this, which, if my observations do not deceive me,
affect the instrument, so as to render it unfit in its present state

as applied to the measurement of Heights. SS5

for the measurement of heights, unless in peculiarly favourable
circumstances. *

The experiments from which I expect to deduce these re-
sults were made by me so far back as 1825 : -|- having been
led by some previous observations to doubt the speedy accom-
modation of the instrument to the condition of the air, as stated
by Mr Adie in his small work which accompanies the sym-
piesometer, I resolved to institute a series of observations
on the subject upon the same spot of which I had already ob-
tained the approximate height, and by taking the indications
at short successive intervals, to discover in how long a time the
sympiesometer might in all cases be considered to have taken
its final level, which is the most important practical question
in the use of an instrument. It was with much vexation that
I found, after many trials, that this time seemed quite indefi-
nite, and often appeared as if it would never arrive, as even
after hanging an hour, the oscillation continued. I threw the
observations aside as hopeless ; and it was only at a later
period that I saw some chance of drawing inferences from them
which might explain the anomaly they disclose, and now, after
nearly four years, I give them to the world in hopes of excit-
ing farther inquiry on the subject, and to suggest, or at least
point out, the mode of discovering a cure for the defect.

It will be proper, first, to explain what I conceive to be the
great fault of the instrument, and then endeavour to substan-
tiate it by the detail of my observations. It will readily be
admitted that the cylindrical receptacle at the top of the instru-
ment, which we may suppose on an average to be 2 inches long
t and I in diameter, which is filled with the most diffuse known
fluid, hydrogen gas, must be incomparably sooner affected by
any change of temperature than the large bulb of a thermo-
meter, intended to have degrees of great size, and which ex-

• Besides these objections, a very important one has been established by
a very complete set of experiments, recorded in the Edinburgh JEnci/clopw-
dia. Art. Meteorology , p. 173, that a gradual absorption of the gas by the
oil takes place, raising the indications of the instrument.

t I must here acknowledge the important assistance which I received in
ihe prosecution of these experiments from ray brother Mr C. Forbes.

336 Mr Forbes on the Defects of the Sympiesometer,

poses a cylinder of mercury, the most dense fluid discovered,
of perhaps an inch-Jong and \ in diameter. This we appre-
hend will be readily admitted ; and it is equally incontroverti-
ble, that the accuracy of the sympiesometer fundamentally de-
pends on the precision of the correction for changes of tempe-
rature, elegantly performed by a sliding scale. Whence, if
the atmosphere be in a variable condition, and we shall find
that at almost all times it is sufficiently so to produce an ef-
fect, the thermometer, from its less sensibility than the ma-
gazine of hydrogen, which is the important part of the instru-
ment, (the oil acting merely as an index), will show a tempera-
ture more or less different from that required for the true cor-
rection, which will therefore be erroneously made. Suppose
the temperature of the air sinking, (for in the case of heights
the instrument, at one station at least, may be presumed to be
in the open air,) the instrument itself will have parted with a
minute quantity of caloric before the thermometer. The scale
therefore depending on the latter will be pushed lower down
than if the true temperature had been indicated, wherefore
the oil will stand opposite a higher point on the sliding scale,
which is divided into inches of mercury,- and a logarithimic
line of fathoms, than indicates the actual pressure of the atmo-
sphere. Conversely, if the temperature be rising, the pres-
sure indicated will be too small.

If this source of error was ever thought of, probably it was
considered too minute to be sensible. We must therefore en-
deavour to substantiate it by experiments, in detailing which,
I would premise, that, as far as they go, I put perfect confi-
dence in their accuracy, though I could wish some additional
observations had been made, both under circumstances consi-
derably different, and in repetition of the observations on re-
turning to the first station ; though the latter precaution we
shall find will little affect the general conclusions.

The upper station, which we shall designate by A, was the
room in which the sympiesometer usually hung in Colinton
House, at 399 feet above the mean level of the sea. The
lower one, B, was on the bank of the Water of Leith, in a
deep valley, which offered a very fit locality for barometric ex-

as applied to the measurement of Heights, 337

periments. Its level below station A I ascertained with the
nicest accuracy, by levelling with a theodolite by Troughton,
to be 141.1 feet. From a mean of some single observations
made with the sympiesometer in the spring of the same year,
I obtained nearly a similar result. The observations now to
be detailed were made in the height of summer, and their great
discrepancy in some cases from the real height indicate, I fear,
some more fundamental want of compensation than in the
mere horary variations of temperature. Without regarding
the order of dates, we shall commence with the most irregular
sets of observations, and go on to those more accordant with
the result by levelling, and more accurate in themselves. The
mode employed was, after making the observation at the
higher station, to proceed as quickly as possible to the other,
and after the cork which closes the cistern of oil had been open
generally from two to four minutes, the register commences, and
was continued every five minutes for an hour, with the purpose
of discovering the ultimate time required for the self-adjust-
ment of the instrument. We shall arrange them in tables ac-
cording to each day's observations, and make our remarks on
each. The height of the sympiesometer is given in inches, and
also in fathoms, as marked on the scale, and the column of
DilF. indicates the difference of level in fathoms indicated be-
tween the two stations, but which of course requires the usual
thermometric correction for the temperature of the air, as in
measurements by the barometer.

Table

l.—Aug,

2J, 1825.

No.

Stat.

Hour, P.M.

Therm.

Sympiesoj
Inches.

neter.
Path.

263

JOiff.

Q^m

f>9.0

29.18

6.30

62.8

29.37

233

—30

.-.

6.35

62.3

29.41

228

6.40

61.4

29.41

228

—

6.45

60.9

29.41

228

—

6.50

60.6

29.42

227

—

60.2

29.42

227

—

7.00

59.9

29.42

226

—

7.05

60.2

29.46

222

VOL. X. NO. II. APRIL 1829.

338 Mr Forbes on the Defects of the Sympiesometer,

7M0'

60.B

29.48

218

—

7 .15

60.1

29.45

223

—

7.20

59.9

29.44

224

—

7.25

60.3

29.46

221

14 — 7.30 60.3 29.46 221 42

This is the worst set of observations I have obtained, and
in many respects they are unsatisfactory. We may see, how-
ever, that the general disposition of the thermometer to fall is,
as by our hypothesis, accompanied with a uniform rise of the
sympiesometer, interrupted by the stationary aspect, which
during a rise is equivalent to a descent in Obs. 6 to 8, which is
succeeded and accounted for by the rise of the thermometer in
Obs. 8 to 10, as it is obvious that the thermometer upon our
supposition will only indicate the change after its effect has
been manifested in the gaseous column. The only other in-
stance of a fall of the sympiesometer is between Obs. 10 and 12,
and which is equally promptly accounted for by the rise of the
thermometer at Obs. 13. The column of differences is far too
great, since when corrected for temperature the height ought
to be only 23.52 fathoms. The positive height, however, is
not our present subject of examination. I will only observe
farther, that there are 10° between the temperature of the two
stations ; and if there be any constant defect of compensation,
the error would be, as we have shown, in making the height
too great.

Table II — June 2Ut, 1825.

No.

Stat.

Hour, P.M.

Therm.

Sympiesometer.
Inches. Path.

Diff.

3M0'

29.46

221

«_

3.30

55.1

29.55

208

—13

—

3.35

54.3

29.65

196

—

3.40

54.6

29.70

186

3.45

53.8

29.72

185

—

S.50

53.6

29.72

185

—

3 ,55

53.6

29.73

183

—

4.00

53.8

29.74

180

—^

4.05

53.8

29.74

180

24 — 4.10 53.2 29.74 180 41

applied to the measurement of Heights.

4M5'

52.8 29.74 180

—

4.20

52.4 29.70 185

—

4.25

52.3 29.74 182 '

—

4.30

52,4 2-9.74 181

339

This, which is one of the worst sets, must be imputed, like
the last, to those unaccountable uncertainties which affect ba-
rometric measurements, particularly in cases like this, where the
height is small, and one of the stations in a ravine liable to acci-
dental changes of temperature and partial currents of air. But
the inconsistency of the indications between spaces of five mi-
nutes is the point we have to remark, and the general charac-
ter of the series amply confirms the assumption with which we
set out. Theyall of the thermometer is continuous until the
last observation, when it rises 0°.l, and we notice an equally
regular rise in the column of differences till the last three ob-
servations, when it is very clear the atmosphere had been in-
fluenced by some agencies contrary to the decline of the diur-
nal temperature, which, though not indicated by the mass of
mercury till Obs. 28, had begun at Obs. 26 to influence the
magazine of hydrogen. Such a series as the one before us
shows how perplexing an instrument the sympiesometer must
sometimes be, since in this case, even after the tedious delay
of an hour, we should have the greatest difficulty in selecting
the height most to be depended on.

The following I consider a very important series.

Table III.— /w/^r 19j5^ (?) 1825.

No.

Stat.

Hour, p. M.

Therm.

Sympiesometer.
Inches. Path.

Diff.

2H0'

70.6

29.81

170

— .

3.00

66.4

29.96

148

—22

—

3.05

66.4

30.00

143

—

3.10

66.5

30.00

143

—

3.15

66.5

30.02

141

—

3.20

66.3

29.96

149

3.25

66.4

29.99

144

3.30

65.7

30.00

143

3.35

65.2

30.01

142

"640 Mr Forbes wi tJie Defects of the Syvipiesometer^

—

3^40'

6^.^

30.06

135

—

8.45

m.9.

30.02

140

...

3.50

66.0

30.00

143

3.55

65.9

30.01

142

...

4.00

QQ.9.

30.04

138

It is clear from our explanation of the irregularities of the
sympiesometer that the cause (viz. any change of tempera-
ture) must be indicated by the thermometer after the irregu-
larity has been observed, since the explanation is founded on
the inaptitude of the thermometer to receive speedily slight
impressions. In the two former tables, where the tempera-
ture uniformly declined, the sympiesometer uniformly rose ;
and here, where the thermometer undergoing irregular changes,
and being nearly as high at the end as at first, the sympieso-
meter exhibits similar irregular movements. A little attention
to Table 3 will show that the changes incident to the indicated
height are succeeded shortly by such changes in the thermome-
ter, as, according to our hypothesis, form an explanation of them.
Thus the rise of .02 inches at Obs. 32 and 33, is succeeded
by a fall of 0°.2 at Obs. 34, and the fall of the oil at Obs. 34
had been caused by an evanescent current of air, producing
at Obs. 35 a minute rise of the thermometer. The continuous
rise of the oil in Obs. 35 to 37 is satisfactorily accounted for
by the considerable fall of the temperature from 66.4 to 65.2 in
the same observations ; nor can we doubt that the thermome-
tric rise of P.3 in the succeeding observations was accidental
from the approach of the body of the observer to the thermo-
meter only, since it descends immediately after, and since the
problematical rise of the instrument is readily explained by the
partial heating of the thermometer. Had it not been for this
obviously accidental heating, the oil, instead of declining,
would in all probability have risen steadily, till Obs. 39, ac-
companied with the descending temperature, indicated by
the thermometer in Obs. 39 to 41, where a rise is again ex-
hibited which had already affected the oil at Obs. 40. The rise
of the oil in the two last observations is to be imputed to an-
other descent of temperature not indicated when the obser-
vation ceased.

as applied to the measurement of Heights, 341

Table IV — July 5th, 1825.

No.

Stat.

Hour, P. M.

Therm.

Sympiesometer.
Inches. Path.

Diff.

4'>00'

29.78

175

4.05

63.8

29.86

164

—11

—

4.10

64.3

29,69

188

+ 13

4.15

62.8

29.83

168

— 7

___

4.20

62.3

29.92

156

—

4.25

62.6

30.00

144

4.30

61.6

30.00

144

4.35

61.4

30.00

144

4.40

61.0

2997

146

4.45

60.4

29.95

150

4.50

60.3

2997

146

—

4.55

60.2

29.96

148

—

5 .00

60.0

2996

149

From this series we can hardly draw conclusions either for or
against the theory we propose ; the first part being favourable
to it, and the latter observations exhibiting the unusual con-
currence of the descending thermometer with descending oil.
We would notice the extraneous motion at Obs. 45, as being
certainly occasioned by the accidental contact of the person of
the observer with the instrument, which raising the mercury
0°.5, had imparted a much larger portion of caloric to the hy-
drogen gas, and caused the descent of the oil to a great ex-
tent. The temporary rise of the thermometer at Obs. 48 seems
to have given the turn to the oil, which becomes stationary,
and afterwards descends without apparent cause. It is remark-
able that the last three or four observations give the height
much more nearly than when the instrument stood for ten mi-
nutes together at 30.00 inches.

Table V.— /% m, 1825.

, NO. Stat. Hour, P.M. Therm. .^S'^''^''^'!. ^^^' '

56 A 6^4i(y 65.8 2978 185 —

57 B 6.45 63.8 29.88 160 —25

58 — 6.50 61.2 2990 158 27

842 Mr Forbes on the defects of' the Sympiesometer,
59 B Q^.^B' 60.2 29.90 158 27

—

7.00

59.7

29.92

154

— .

7 .05

59.3

29.92

154

—

7.10

59.4

29.94

152

7.15

59.3

29.94

152

—

7.20

58.8

29.92

154

—

7.25

58.7

29.94

152

—

7.30

58.9

29.95

150

7.35

58.6

29.95

150

—

7.40

58.3

29.95

130

This table seems peculiarly fitted to verify our hypothesis, and,
if taken singly, would be no insufficient proof of its correctness.
The general tendency of the sympiesometer is to rise, and of the
thermometer to sink, but their minuter oscillations prove more
closely their connection. The fall of the latter is steady, ac-
companied by the ascent of the former, till Obs. 60, where the
stationary condition of the oil is succeeded by an evanescent
rise of 0®.l in Obs. 62. The subsequent descent of .02 in the
oil is perfectly accounted for by the almost stationary condi-
tion of the thermometer at Obs. QB^ and its rise of 0°.2 at Obs.
6Q> When its renewed gradual descent continues to raise the
sympiesometer, or render it motionless till the conclusion of
the series : the positive height indicated is much too great.

Table VI.— July 9.0th, 1825.

No.

Stat

Hour P.M.

Therm.

Sympiesometer.
Inches. Fath.

Diff.

3^55^

69.5

29.79

174

— .

4.02

66.0

29.80

172

— 2

—

4.05

64.4

29.84

166

—^

4.10

63.3

29.98

148

—

4.15

62.8

30.02

139

—

4.20

62,8

30.02

139

.—

4.25

62.6

30.02

139

4.30

62.4

30.02

139

—

4.35

62.4

30.03

138

— .r

4.40

62.0

30.02

140

—

4.45

62.6

30.02

140

as applied lo the measurement of Heights. 343

4\50'

m.Q

30.02

139

—

4^M

m.Q

30.02

139

5.00

62.4

30.02

140

After watching the sympiesometer in its most fluctuating
state, it is pleasing to find, in a series like the one before us,
that in its remarkable steadiness, which is greater than I ever
observed, our supposition is completely backed by the unifor-
mity of temperature very singular for such a time of day. The
cistern was opened at the instant of the first observation at
the lower station, and after two more observations, it seems to
have acquired the temperature of the air, which continued for
45^ with an extreme variation of only 0°.8, which occurred but
in one instance. We may therefore easily account for the ex-
traordinary unity of the columns of the sympiesometer, though
it is not so easy to explain why the height is so much greater
than it ought to be ; but that is not to our present purpose.
The only variation which breaks the column of inches between
Obs. 72 and 82, is of .01 at Obs 77, and is immediately suc-
ceeded and accounted for by a sudden fall of 0°.4 of the ther-
mometer, which is actually double of any fall of the thermome-
ter within the same limits. This seems to prove to demon-
stration the accuracy of our explanation.

Table VII.— -/wZ^ 30^^, 1825.

No.

Stat.

Hour P.M.

Therm.

Sympiesometer.
Inches. Fath.

DifF.

2^.35^

73.1

29.46

222

—

2.40

77.2

29.50

216

— 6

—

2.45

77.4

29.54

208

...

2.50

76.1

29.55

207

-.^

2.55

76.2

29.60

200

—

3 .00

75.6

29.61

199

—

3.05

75.0

29.61

199

—

3.10

75.0

29.60

201

—

3.15

74.8

29.59

202

—

3.20

74.1

29.60

201

—

3.25

74.1

29.60

200

—

3.30

74.3

29.61

198

95 — 3.35 74.5 29.63 196 26

34f4 Mr Forbes on the dejects of the Sympiesometcr,

This table I have placed the last of the series, because the
heights it indicates are pretty regular, and approach to the
true altitude far nearer than any of the others ; and it is well
worthy of observation, that it appears to be the only instance
of the temperature of the lower station being equal to or
greater than that of the upper. This surely indicates some
permanent want of compensation of temperature. In this set
the thermometer generally falls, and the sympiesometer gene-
rally ascends to the conclusion of the observations. Some
small fluctuations not exceeding one or two hundredths of an
inch occur, and the oscillations of the thermometer, contrary to
the diurnal decline of temperature, do not exceed 0°.2 between
any two observations.

I shall conclude these experiments by giving the results of
one of a very simple nature, in which the instrument was re-
moved from station A to one about a fathom lower (D,) an apart-
ment partly^ under ground, and with a pretty free exposure to
the changes of external temperature, it will serve to confirm
our former results. The instrument was ascertained to be ex-
actly at the same height some time after its return to station A.
The column Diff. in the following table merely indicates the
successive differences of the height of the sympiesometer.

Table VIII.— /ww6? \^th, 1825.

No. Stat. Hour p. m. Therm. Sympiesometer. Diff.

^^W

67.6

29.695

2.45

65.1

29.60

—

2.50

64.6

29.69

+09

—

9^,55

63.3

29.71

4-02

100

—

3.00

63.1

29.74

+03

101

—

3.05

62.4

29.74

102

—

3.10

62.4

29.75

+01

—

3.15

62.4

29.77

+02

101

—

3.20

62.0

29.75

—02

105

..—

3.25

62.0

29.75

106

—

3.30

61.4

29.74

—01

107

—

3.40

62.0

29.74

]08

—

3.45

61.6

29^.72

—02

109

—

3.50

61.6

29.74

+02

as applied to the measurement of Heights. 345

110 D 3^55' 61.3 29.72 —02

111 — 4.00 61.4 29.74 +02

From Obs. 97 to 105, the thermometer falls, and the sym*.
piesometer, with one exception, uniformly rises. The fall of
.01 at Obs. 106 is caused by a change indicated by the fall of
no less than 0°.6 of the thermometer at the next observation.
The descent of the oil between Obs. 107 and 108 is succeeded
in Obs. 109 by a stationary thermometer, which in the course
of falling is equivalent to an initial rise. The ascent of the oil
in Obs. 109 is followed by the descent of mercury in Obs. 110,
and the renewed fall of the former in Obs. 110 is produced
by the cause which is indicated in the contrary motion of the
mercury in Obs. Ill, so that this curious oscillation is preserv-
ed five times ; the motion of the sympiesometer always preced-
ing that of the thermometer, as it ought to do according to
theory.

Regarding the very erroneous results of height which many
of the preceding tables give, I own I feel it difficult to give
an explanation, more especially as several trials I made in
spring agreed far better with the actual height, when the dif-
ferences of the attached thermometer were of course greater
My experiments are too limited to draw positive conclusions
on this point, which is not the one I aim at ; and I shall con-
tent myself with noticing two possible sources of error. That
the instrument (which I believe is graduated wholly experi-
mentally) may not have been subjected to sufficient degrees
of heat, which in these experiments was so considerable ; and
that the situation of the experiment was such as to render it
trying to barometric measurement, being a ravine where pro-
bably very various currents prevail, particularly in warm wea-
ther. I hope at a future time to continue my experiments on
the use of the sympiesometer, and in the meantime to excite
some attention to the subject.

I promised, before concluding, to give some hints for the re-
moval of the defect I suspected, and as my paper is now longer
than I intended, I shall do so in a few sentences. Since the
the main point is, that the thermometer should indicate the
actual temperature ef the hydrogen gas, I should recommend

346 Dr Grant on the hifluence of Light

that the bulb be actually inserted in the magazine which con-
tains it, and the stem being turned down, should run parallel
to the instrument, the degrees running downwards, which is
actually the direction they assume on the lower scale upon
which that of inches and fathoms slide. Farther, though
this I think would nearly obviate the evil, the bulb of the
mercurial thermometer might advantageously be made much
smaller, and a very minute hut flattened bore applied. Thus the
degrees would be rendered smaller ; but if they were only half
their present size, the accuracy, I am convinced, would be ad-
vantageously transferred from the minuteness of the adjust-
ment of the scale to the certainty that that adjustment, as
nearly as it could be made, would be in its principle correct.
A nice eye would discern the tenth of a degree if aided by
skilful graduation, though no larger than half what they
are at present, and a lens might even be provided. The ma-
gazine of hydrogen should also be more defended than at pre-
sent from the influence of the breath of the observer ; and even
were the position of the thermometer not to be altered, the se-
clusion of the gaseous bulb from the more immediate action of
atmospheric changes, would be advantageous, by rendering it
more similar in condition lo the mercury. Other precautions
will doubtless occur to practical men, for the remedy of the
defect I have endeavoured to prove, if my deductions be correct.
In conclusion, I have only to observe, that my animadver-
sions of course apply to the sympiesometer merely as used in
the measurement of heights ; as a marine barometer, its supe-
riority in accuracy and utility, as well as convenience, seems
fully established.

Aet. XXIII. — On the influence of Light on the motions of
Infusoria. By R. E. Gkant, M. D., F. R. S. E., F. L. S.,
Professor of Zoology and Comparative Anatomy in the Uni-
versity of London. Communicated by the Author.

\ Many animals appear sensible to the impression of light which

^ have obviously no distinct organs of vision, and some even

which exhibit no trace of a nervous system are notwithstand-

on the motions of Infusoria. 3 47

ing perceptibly influenced by that agent. Actinice placed
alive in basons of sea water I have observed to move slowly
along the sides of the vessels till they reached the most shaded
situation, where they generally remained stationary, and they
appear to shun the light in their native element. I have often
verified the observations of Trembley on the fondness of the
Hydroe for light. When placed in a glass jar with pure wa-
ter, they quickly betake themselves to the illuminated side of
the vessel, and collect in that situation. In their natural abode
they show their partiality to light by approaching to the sur-
face of the water, where they are generally found adhering to
the stalks of floating Lemnce. When we watch the motions of
Meduscc floating in the sea, we generally observe them change
their direction as they approach the surface, and direct their
course downward before any part of their body has come into
contact with the atmosphere. From seeing this often take
place where the water was quite still, I have been induced to
believe that the delicate transparent texture of the animal was
sensible to the blaze of the sun's light as it approached the
surface. I have elsewhere remarked that even the ova of some
zoophytes preferred to attach themselves to the shaded parts
of the vessels in which they were placed. From the soft ge-
latinous texture of such beings, indeed, it seems natural to ex-
pect that an agent impinging on them with such velocity and
in so great a quantity as the rays of light, and which pene-
trates their whole substance, should be able to affect them in
some manner, were it only with impressions of touch. And
the examination of the localities and the particular positions
habitually assumed by the lowest species of fixed and nerveless
animals, where the temperature and pressure do not vary, lead
us to conclude that their physical distribution is principally
determined by the intensity of light.

From the minuteness of the Infusoria and their transparent
colourless texture, and also from the manner in which they are
generally examined, in watch-glasses under the microscope,
the influence of light on their motions has probably escaped
notice. The motions are most easily observed in those which
have a perceptible magnitude with some degree of opacity and
a lively colour, as the Furcocerca viridis of Lam. (Cercaria

348 Dr Grant on the mfluence of Light

viridis of Muller and Bruguiere), which is perceptible to the
naked eye, and has a briglu grass-green colour. This animal-
cule is found in the summer season in stagnant pools of fresh
water, where it forms a thin green film on the surface. It was
observed by Muller in this situation in the fresh water pools
of Denmark, and it is found in the same situation in stagnant
pools near London. Muller observed that when these animal-
cules were placed in a vessel of water, they collected at the
margin, and died by the evaporation of the water, leaving a thin
green film on the side of the vessel. In the month of August
last I observed a light-green film on the south side of a small pool
of stagnant fresh water near London ; it covered detached por-
tions of the surface and extended over more than twenty square
feet. As it did not appear to the naked eye to be produced
by the green leaves of any plant, I placed a small portion of
the film in water under a pocket microscope and observed that
the whole green matter detached itself into separate lively ani-
malcules with a tapering bifurcated tail, and corresponding ex-
actly with the figures and descriptions of the Cercaria viridis,
given by Muller in his Animalc. Infus. (tab. 19, fig. 6 — 13),
and by Bruguiere in the Encyc. Meth. (pi. 9, fig. 6 — IB).
Lamarck has made a distinct genus, Fitrcocerca, of those Cer-
carice of Muller which, like the present species, have a bifur-
cated tail.

The water containing these minute animalcules was placed
in a shallow crystal vessel near a window that I might observe
their motions and appearance. Under the microscope they ex-
hibited a granular or vesicular texture, but presented none of
those spots which Muller mistook for eyes in some other spe-
cies of Cercarice. After remaining about two hours I observed
my green animalcules all accumulated at the surface of the
water on one side of the vessel, and nearly left dry on the
shallow margin by the rapid evaporation of the water. Think-
ing that some slight inclination of the vessel to one side might
have caused them thus to accumulate at one part of the mar-
gin, I turned that part slowly to the opposite side, added a
small supply of water, and agitated slightly with the water the
animalcules which had nearly perished by the evaporation.
On inspecting them a few hours afterwards I found them all

on the motions of Infusoria. 349

again accumulated at one side of the surface of the water, and
as it happened both times to be the side next the window where
they were collected, I suspected that, like the Hydrce, they might
have been attracted to that side by the influence of the light.
I now removed the vessel to the opposite side of the window,
that the light might reach it by a different direction, and in about
an hour I found that they had again collected precisely on the
part of the margin nearest to the light. The vessel was after-
wards placed at various distances from the window, and in vari-
ous directions with regard to it, and in more than twenty suc-
cessive trials, I found the animalcules invariably betake them-
selves to the most illuminated point of the margin. On turn-
ing the vessel gently round from the window, I could observe
the animalcules with a pocket lens bound forward almost in a
straight line to the light, after slowly detaching themselves
from the side where they had previously accumulated. When
they are swimming dispersed through the water, they seem to
have disappeared, being almost invisible to the naked eye
when thus separated, and exhibiting an intense green colour
only when collected closely together.

The presence of eyes in such animals has been ridiculed by
later naturalists, as implying the existence of an optic nerve,
a centre of nervous energy, and a general complicated organi-
zation, which are contradicted by microscopic inspection. The
motions of Infusoria are by many believed to be automatic,
and Lamarck conceives them to result merely from the action
of various imponderable fluids pervading all bodies. Distinct
organs of vision belong only to those animals which require
to modify the light, so as to produce images of distant objects,
to enable them to shun their foes, to select their proper food,
or to provide for the continuance of their race, and are not
met with in the Infusoria, Zoophyta, or Radiata. It is inte-
resting, however, to observe, that an agent so extensively dif-
fused over nature as light has an obvious and powerful influ-
ence on the motions of the Furcocerca viridis, an animalcule
which exhibits nearly the simplest known form of animal orga- /
nization. — — '

350 Dr Granfs Observations on the Virgularia Mirahilis.

Art. XXIV. — Further observations on the Generation of the
Virgularia mirabilis. By R. E. Grant, M. D., F. R. S. E.,
F. L. S., Professor of Zoology and Comparative Anatomy
in the University of London. Communicated by the Au-
thor.

In a former notice regarding the structure of the Virgularia
mirabilis^ Lam. (Edinburgh Journal of Science, vol. vii.
p. 332,) I observed that the small round white ova are seen,
in spring, ranged in a double transverse row under each of
the lateral fleshy expansions, and that when mature they pro-
bably pass out through the bodies of the polypi, as in some
other nearly allied zoophytes. This conclusion, founded on
analogy, I had an opportunity of confirming by observing the
process of generation in this animal in April last. Specimens
were brought me alive to Edinburgh from the same part of
the Frith of Forth with those of the preceding year, and by
carefully supplying them with pure sea water they were pre-
served in a healthy condition for several weeks in long glass
tubes, that I might more closely examine them with a lens
without in the least disturbing their motions. The white ova
under the pinnae, close to the stem, were of considerable size,
and caused the fleshy substance to project at these parts like
small external vesicles. I had the satisfaction, however, to ob-
serve the ova advance slowly upwards into the bodies of the
polypi which compose the whole substance of the pinnae, and
during this passage they acquired a yellowish white colour, a
more regular spherical form, and a greater size. As they ap-
proached the base of the stomach they appeared to enjoy more
freedom, and on examining them in this situation with a lens,
through the sides of the glass tubes, I could distinctly per-
ceive the ova in the same restless state as I had observed the
red ova in the polypi of the Lobularia digitata. They ob-
viously contracted themselves in different directions, they
changed their positions, and sometimes they appeared as if
revolving round their own axis. On escaping from the body
they exhibited the same slow spontaneous motions as in the
Lobularia. It is interesting to observe this singular law re-

Dr Adam on the Mantis Tribe, 351

garding the generation of zoophytes thus gradually extended
by the cautious observation of individual facts.

A very remarkable hisus naturoe of this animal was brought
me along with the other specimens. It measured nineteen in-
ches in length, and had lost the central calcareous stem of its
upper half. The lower half of the animal had the usual
structure and a healthy appearance, but the portion which
had lost the axis was cylindrical and smooth like a worm, with
a clavate termination, and without the slightest appearance of
pinnag or polypi on any part. The pinnae of the healthy por-
tion diminish gradually in size from the middle to near the
commencement of the smooth vermiform half, which was
equally alive with the other, though very differently formed.
This remarkable specimen of the Virgularia mirabilis is pre-
served in the Zoological Museum of the University of Lon-
don.

Art. XXV.— zoological COLLECTIONS.

1. Observations on the Mantis Tribe, or that of the Leaf Insects.* By
Dr Adam.

Or all the insect tribes in India that of the Leaf Insects is the most re-
markable for external form. According to the latest classification, this
tribe has been divided into the two families of the Mantida and Phasmida,
founded on a difference in the structure of the foot or leg ; this member in
the former being raptorious, is provided with a sharp claw, and a hollow
on the leg and thigh, and a double series of spurs, for the better securing
its prey ; and in the latter, being destitute of any such peculiarity. Dr
Adam calls two of the specimens laid before the Committee Gongylodes, as
ihey appear to correspond closely with the description and figure of that
species in the latest entomological works. This insect, when alive and
fresh, presents a striking resemblance to a blade of grass, differing in co-
lour according to the season, being green and succulent in the rains, and
in the dry weather, so much like a withered straw, that they can with dif-
ficulty be distinguished. On first beholding this insect, during the hot
winds in the upper provinces, Dr Adam could hardly be convinced that it
was not straw, and part of the same long and dry grass on which it rested.
A slight movement of the headj however, like that of the house lizard,
on the wall, when watching its prey, satisfied him that it was a living ob-
ject, and on removing grass and all to his hut for examination, he was both
surprised and amused at the extraordinary powers which the insect deve-
loped. Clinging close to the upright straw which was fixed on the table,

• Read at a meeting of the Physical Committee of the Asiatic Society of Calcutta.

SSZ Zoological Collections.

)the animal lay in wait for its prey, with no less design than would be ex-
hibited by a cat or a tiger, and if an unlucky fly happened to alight in his
neighbourhood, there was hardly left to it a chance of escape. He projects
rapidly his armed paw, and, with unerring aim transfixing his victim,
lodges it in the toothed hollow of the thigh, destined for its reception.
After the fly is in his power, no time is lost in devouring it, commencing
with the trunk, and in a few minutes swallowing the whole, the head and
wings constituting the finishing morsel. In this manner he would destroy
at a meal five or six large flies, which, in point of bulk, nearly doubled his
own body.

On viewing the structure of the fore-limb of this tnsect, it seems impos-
sible to imagine any thing more perfectly contrived for the end in view.
The limb itself so strong and muscular, provided with a claw at its extre-
mity, likewise strong, horny, and sharp as a needle, and the groove in the
last joints, with the double row of teeth or spurs on the margin, correspond-
ing and locking closely into each other, like the fangs of the alligator, al-
together constitute an apparatus for seizing and securing its prey, which,
in so small a creature, cannot but excite admiration. By means of these
formidable weapons, the insect not only becomes destructive to others, but
is employed to attack its own species ; and in China, we are told, fighting
the mantis forms as much the favourite amusement of boys, who carry them
about in cages for the purpose, as cock-fighting in England, or among the
inhabitants of the Eastern Islands.

2. Account of a Singular Species of Mollusca from the Coast of Ceylon *
By James Calder, Esq.

The specimen of this animal presented to the Society was sent to Mr
Calder by Captain White, commanding the ship Sherborn, who gives the
following account of the manner in which it was procured by him : —
While passing Ceylon, he says, a boat came off, in which was this curious
sea-anirnal. We had never seen any thing of the kind before, and the na-
tives appeared to have a great dread of them, as they gave an account of the
large ones, on being touched, possessing the power to destroy the use of a
man's arm. It lives on the weeds which grow on the rocks, and is fre-
quently found on the Coast of Ceylon. It is observed, that, from several
circumstances in its anatomical structure, the species would appear to rank
among the Asterias ; but it differs materially in other respects from the spe-
cies described by systematic writers, and presents a peculiarity of external
form that does not belong to any of the Mollusca, as far as his acquaintance
with this order extends. It is, however, chiefly interesting from the reported
power it possesses, as alluded to by Captain White, of benumbing or de-
stroying the ability of a person's hand touching it, resembling in this point
the Torpedo liaia, and Gymnotus electricus. It seems strange, however,
that no mention should have been made of an animal of this description by
any of the authors who have written on Ceylon and its natural productions.
The subject is deserving of further inquiry, and, should the native account
be confirmetl, we shall have obtained a most interesting addition to our
zoological knowledge in the animal now under consideration.

• Read at a meeting of the Asiatic Society, June 13, 1828.

M. Flourens' Experiments on the Ears of Birds, 353

3. Experiments on the effects produced by dividing the semicircular canals

in the Ears of Birds. By M. Flourens.
At the meeting of the Academy of Sciences of Paris on the 15th Sep-
tember last, an interesting report was presented by MM. Portal, Guvier,
p-nd Dumeril, on the experiments of M. Flourens, relative to the effects
produced by dividing the semicircular canals of the ear in birds. This
physiologist had already ascertained that the membrane of the tympanum
might be removed without affecting hearing ; that taking the stapes out
of the groove which forms the fenestra ovalis weakens sensation ; and that
the destruction of the pulp of the interior of the vestibule annihilates it.
These results might to a certain extent have been anticipated ; but expe-
riments on the semicircular canals produced effects altogether unexpected.
Their section did not appear to weaken the sensibility to sounds, but only
to render it painful ; while the movements of the animal occasioned by the
separation of the parts struck M. Flourens with surprise. He had for-
merly, in November 1824, announced this fact with regard to the horizon-
tal canals, and subsequent experiments on the others have led to new re-
sults. The semicircular canals in the ear of birds, being protected merely
by a thin osseous plate, are surrounded by a slight covering of cellular sub-
stance, or by openings which communicate with the cavity of the tympa-
num. One of the three adheres to the internal wall of the cranium ; the
two others approach more to the external wall, and, crossing one another,
one goes in a horizontal plane from right to left, the other in a vertical di-
rection forwards and backwards. The experiments of M. Flourens were
upon these three canals. The section of the horizontal canal constantly
produces a motion of the head from right to left, and vice versa; and when
the two horizontal canals are divided, this motion becomes so rapid and
impetuous, that the animal loses its balance, and rolls over and over with-
out the power of raising itself. If the semicircular vertical external canals
be cut, a violent motion upwards and downwards takes place ; the animal
does not turn round, or roll ov€:;r and over, but falls, often in spite of exer-
tions to the contrary, on its back ; and lastly, the section of the semicircu-
lar vertical internal canals^roduces violent motions upwards and down-
wards, but the animal in this case always falls forward on its bill and tum-
bles round in that direction. These motions cease when the bird re-
mains at rest ; but as soon as it attempts to change its place they are re-
newed, and flight or walking is rendered totally impracticable. - The sec-
tion of all these canals induces violent and surprising motions of the head
in every direction. These phenomena do not take place on simple destruc-
tion of the osseous envelope of the canals, unless the membranous canal
and the pulp with which it is filled be also divided.

An extraordinary circumstance attending these experiments is, that the
involuntary motions do not prevent the healing up of the wound, the ani-
mal from feeding as usual, and even getting fat. Still however the mo-
tions are continued, and M. Flourens has seen pigeons upon which he had
operated, and afterwards fed with care, for many months, and even up-
wards of a year, fall into the peculiar motions and tumblings corresponding
to the divided canal, whenever they attempted to change their position.
VOL. X. NO. II. APRIL 1829- Z

354 History of Mechanical Inventions and

In other respects the birds exercised all their functions, hearing and seeing,
eating and drinking as usual.

M. Flourens repeated his experiments in presence of MM. Cuvier and
Dumeril, with the same results ; and however surprising and inexplicable
they may be, there seems no doubt of the facts as stated. — Revue Encyclo-
p^dique, Sept. 1828. Pp. 781—784.

Art. XXVI.— history OF MECHANICAL INVENTIONS AND

OF PKOCESSES AND MATERIALS USED IN THE FINE AND

USEFUL ARTS.

I. Description of a Differential Barometer, By the late W. Hyde

WOLLASTON, M. D. F.R.S.

This instrument is capable of measuring, with considerable accuracy,
extremely small differences of barometric pressure. It was originally con-
trived with the view of determining the force of ascent of heated air in
chimneys of different kinds ; but as its construction admits of any as-
signable degree of sensibility being given to it, it is susceptible of appli-
cation to many other purposes of more extensive utility. A glass tube, of
which the internal diameter is at least a quarter of an inch, being bent in
the middle into the form of an inverted syphon, with the legs parallel to
each other, is cemented at each of its open extremities into the bottom of a
separate cistern, about two inches in diameter. One of these cisterns is
closed on all sides, excepting where a small horizontal pipe opens from it
laterally at its upper part; while the other cistern remains open. The
lower portion of the glass tube is filled with water or other fluid, to the
height of two or three inches ; while the remaining parts of the tube, to-
gether with the cistern, to the depth of about half an inch, are filled with
oil ; care being taken to bring the surfaces of water in both legs to the same
level, by equalising the pressure of the incumbent columns of oil. If the
horizontal pipe be applied to the key-hole of door, or any similar perfora-
tion in a partition between portions of the atmosphere in which the pres-
sures are unequal, the fluid in the corresponding half of the instrument
will be depressed, while it is raised in the opposite one, until the excess of
weight in the column that is elevated will just balance the external force
resulting from the inequality of atmospheric pressure upon the surface of
oil in both cisterns. This, however, is equal only to the difference between
the weight of the column of water pressing on one side, and that of an equal
column of oil which occupies the same length of tube on the other side ;
this difference depending upon the relative specific gravities of the two
fluids, will, in the case of olive oil and water, be about one-eleventh of the
weight of the column of water elevated. But the sensibility of the instru-
ment might be increased at pleasure, by mixing with the water a greater
or less quantity of alcohol, by which the excess of its specific gravity over
that of the oil may be reduced to one-twentieth, one thirtieth, or any other
assignable proportion. The instrument may be converted into an areo-
meter, by closing both the cisterns, and by applying to the upper part of
each a trumpet-mouthed aperture, opening laterally.

of Processes in the Fine and Useful Arts. 355

^. Account of a method of measuring (he resistance of fluids to bodies paS'
sing through them. By James Walker, Esq. F. R. S. Edin.
As it has been demonstrated that the resistance from friction to a carriage
upon a road or rail-road is the same at all velocities, Mr Walker was de-
sirous of ascertaining the strain upon a boat when moving at different ve-
locities. This experiment was made in the middle of the East India Im-
port' Dock, (1410 feet long, 560 wide, 924 deep,) so that there was no re-
sistance from the sides or bottom of the dock. A spring weighing machine
was fixed near the bow of the boat, the dial laid horizontally so as to be easily
seen by a person on board ; one end of a line | of an inch in diameter
was attached to the back of the spring, the other end was carried ashore
and attached to a rock or barrel, 3 feet in diameter, the frame of which
was firmly fixed in the ground, and the handles of sufficient length for the
necessary number of men to turn the barrel. The velocities were calcula-
ted from the time of passing through 176 yards, or ^^ of a mile, but to
obtain uniform velocity, the boat was at each experiment drawn over twice
the length, and the 176 yards taken in the middle of the distance by two
marks upon the line. The line between the two marks coming to the edge
of the dock was carefully noted by a person stationed there for the purpose.
Three persons at least were on board the boat, one to read off the strain
shown upon the dial every 2 seconds ; one to write them down, and a third
to steady the boat. An exact uniformity of motion by the men at the
handles was obtained by a little practice, by means of a pendulum varying
in length (as a quick or slow motion was required), hung up in sight of
the men, by the oscillations of which they regulated the revolution of the
handles. The weights marked by tHe index of the dial measured only
the resistances to the boat- The following were the results obtained with a
full built boat loaded with 2 tons 2 cwt- exclusive of the men. The length
of the boat on the surface of the water was 1 8^ feet, its breadth 6 feet, its
depth of immersion 2 feet, the whole depth of the boat being 3 feet, leaving
one foot above water, the greatest immersed cross section 9 feet.

TABLE I.
No. of seconds in Velocity per Observed resist- Calculated resist-
passing 176 yards, hour in Miles, ance, or strain in ance, No. 6 being

lbs. on Dial. the standard.

1 124 2.903 15.75 15.04

2 85 4.235 39.50 32.01

3 146 2.465 " 10.00 10.85

4 140 2.571 11.00 11.80

5 145 2.483 11.00 11.00 stand.

6 140 2.571 12.00 11.80

7 120 3.000 14.00 16.06

8 120 3.000 14.00 16.06

The average resistance of Nos. 7, 8, and 10, (low velocities) is 9.41 lbs.
. and the corresponding velocity 2.529 miles. The average of Nos. 1 and 2
-(high velocities) is 42.59 lbs. and the velocity per hour 4.529 miles. The

calculated resistance in these cases would be
: For low velocities 22.04 instead of 28.07
high 38.1 1 42.59

$86 History of Mechanical Inventions and

Mr Walker also made experiments with a light boat 28 feet long, and
on a Thames wherry.

In almost every experiment the resistance showed an increase, amount-
ing to the square of the velocity ; but where the velocity was considerable,
the resistance followed a still higher ratio, and this in open water. In nar-
row canals the increase must be considerably greater. The excess above
the square, is ascribed in a great measure to the raising of the water at the
bow in high velocities, and to the depression at the stern.

If with a speed of 24 miles per hour, 30 tons upon a canal be equal to 7^
upon a level rail-road, a speed of five miles per hour, would, upon the prin-
ciple of the square, bring the rail-road and canal to an equality ; whereas
the above results makes the two modes of conveyance equal considerably
under four miles per houry and gives the railway the decided preference at all
higher velocities.

The following tables will show at once the comparative merits of canal
and railway conveyance.

Land Experiments. Water Experiments.

Velocity per hour, 2 miles 2 miles

Distance passed over, 2 miles 2 miles

Power of engine required, I horse 1 horse

Time occupied, 1 hour 1 hour

Mechanic power expended, I 1

Velocity per hour, 4 miles 4 miles

Distance passed over, 2 miles 2 miles

Power of engine required, ^2 horse 8 horse by theory,

more by experiment.
Time occupied, i hour \ hour

Mechanic power expended, 1 hour 4 by theory, more

by experiment.
In these experiments the resistance per superficial foot was only 1,23,
whereas in Bossut's experiments it was 1 .854. The cause of this does not
well appear ; but we have no doubt of the great accuracy of Mr Walker,
and his method is obviously superior to those hitherto used. As he pro-
mises to continue the subject, we may expect soon to call the attention of
our mechanical readers to new and important results. In the present state
of our commerce and manufactures, we consider the main result of Mr
Walker's paper, viz. the great superiority of land over water carriage, as a
matter of national interest. A fuller account of Mr Walker's experiments
will be found in the Phil. Trans, for 1828, p. 15—22.

3. On the permanent increase of Bulk in Cast-iron by successive heatings.
By James Prinsep, Esq. Assay Master of the Mint at Benares.

In a former paper on .Mechanical Inventions in No. xvii. p. 168, we
noticed the highly important experiments of Mr Prinsep on high tempera-
tures. In the course of these experiments he discovered the very remark-
able fact, that cast-iron acquires a permanent increase of bulk by each suc-
cessive heating. This point is determined by measuring the cubic extent

of Processes in the Fine and Useful Arts. 357

of an iron retort, as ascertained by the weight of pure mercury which it

contained at the temperature of 80°. The actual contents were as follows : —

Before the first experiment, 9.13 cubic inches.

After the first fire, - 9.64

After three fires, - 10.16

But what is more remarkable still, the augrnentation of the bulk of the re-
tort exceeds the dilatation due to the temperature to which it was exposed.
For as iron expands 0.0105 by 180° of Fahrenheit, the increase of bulk
upon 10 cubic inches should be 0.105 X 3 = 0.315 at 1800° of Fahren-
heit, or even the melting heat of silver. Hence we may conclude that the
dilatation of iron is not equable, a result formerly obtained by Messrs
Dulong and Petit.

4. Description of a Sounding-Board in Attercliffe Church, invented by
the Rev. John Blackburn, Minister of AtterclifFe-cum-Darnall, Shef-
field. (From the Phil. Trans. 1828, p. 361.)

This sounding board is represented in Plate II. fig, 9, 10. The material
is pine wood, the surface is concave, and is generated by half a revolution
of one branch of a parabola on its axis.

The distance from the focus to the vertex is =2 feet

The length of the abscissa is =4 feet

The length of the ordinate to the axis Vsi feet

= nearly 5.7
= Had. of outer circle.

The axis is inclined forward to the plane of the floor, see Fig. 10, at
an angle ACD of about 10 or 15 degrees, and elevated so that the speaker's
mouth may be in the focus.

A small curvilineal section is taken away on each side from beneath, that
the view of the preacher from the north and south galleries may not be in-
terrupted ; whence the outer semicircle is imperfect.

This, however, gives an appearance that is not inelegant, and the outer
edge being ornamented with crockets and leaves, and with a pinnacle at the
highest point, and the concave surface being painted in imitation of a ground
oak canopy, the effect of the whole is pleasing to the eye.

A curtain is suspended from the lower edge of the canopy for about 18
inches on each side.

1. By means of this erection the volume of sound is increased in a very
considerable ratio, (perhaps as 5 : 1), and is thrown powerfully, as well as
distinctly, to the most distant parts of the church ; so that whereas for-
merly the difficulty of hearing an intelligible sound was very great, now
that difficulty is effectually removed, e. g.

The preacher was scarcely audible even in the pews near the pulpit, and
not at all in those more remote : he may now be heard in every part,
and nowhere more distinctly than in the west gallery, or under it, on the
ground floor.

2. It should seem that the voice is reflected in a direction parallel to the
axis ; for let A stand in the pulpit, and B stand first in the west gallery,
opposite to the pulpit, and then in the side galleries ; though B is much

358 History of Mechanical Inventions and

nearer to A in the latter case than in the former, he can yet h^ar with de-
cided advantage when opposite to A {i. e, at the greater distance from him.)
The side galleries appear to be benefited rather by the increased volume
of sound, and by the secondary vibrations excited in a lateral direction.

3. It appears also that vibrations, proceeding from a distant point and
moving in the direction of the axis, are reflected from the parabolic sur-
face towards the focus. For let A stand in the pulpit, as before, and B
in a distant point opposite to it, A can then converse with B in a whisper;
whilst C standing at an intermediate point, cannot at all distinguish the
words spoken by B ; he can, however, hear what is said by A. Also, if
B at a distance, opposite to the sounding board speaks, whilst A places
one ear on the focus of the parabola, and one ear towards B, the effect pro-
duced is that of a voice close to the ear, and in a direction the reverse ol?
that from which it really proceeds.

4. The converse of this also appears true from the following experiment.

Let B remain in the situation last supposed, and let A place his face to-
wards the parabolic surface, and his back towards B ; let A now speak,
having his mouth in the situation of the focus, and he will be heard as
distinctly as when his face was turned towards B.

5. If the mouth of the speaker is placed much within oi* without, above
or below the focus, the effect is proportionally diminished.

6. While the figure of the canopy remained perfect, the effect was more
complete ; perhaps it might be improved if constructed longer, or in
other words if continued farther; but the distance of the focus S to the
vertex A, fig. 10, which regulates the curve must depend on the supposed si-
tuation of the speaker, which will vary with the diameter of the pulpit.

Fig. 10 represents a section of the parabolic sounding-board, which is
shown by the line A P B. The axis of the parabola A C is inclined as
shown on the figure, to the horizon. The mouth of the speaker would be
about the focus S, If S />, S P are the directions of the sound incident upon
the board, p gr, P Q will be its direction after reflexion.

5. Account of a Process for producing a beautiful Blue Colour. By M.
Braconnot.
Six parts of sulphate of copper were dissolved in a small quantity of
water ; also, six parts of white arsenic with eight parts of potash of com-
merce, were boiled in water until no further quantity of carbonic acid was
disengaged. This hot solution was gradually mixed with the first, conti-
nually agitating until effervescence ceased. An abundant dull yellowish
green precipitate was formed. About three parts of acetic acid were then
added, or such a quantity that a slight excess was sensible to the smell.
Gradually the precipitate diminished in volume, and in some hours a
slightly crystalline powder was deposited at the bottom of an entirely
colourless solution. The fluid was poured off" as soon as possible ; and the
powder, washed with plenty of water to remove the last portions of arsenic,
was then of a brilliant blue colour.

Care must be taken not to add to the cupreous solution an excess of ar-
seniate of potash, as it causes waste of the acetic acid afterwards added, as
the latter must be in excess. In repeating the process in the large way, an

of Processes in the Fine and Useful Arts. 359

arseniate of potash, prepared with eight parts of oxide of arsenic, instead
of six, was used, and the result was very successful. M. Braconnot thinks
that probably a slight variation of the proportions he has given may be
found advantageous ; but, in the meantime, considers it right to give the
best process he is able for the preparation of a colour so beautiful, and
which may be very useful in the arts.

6. Account of the Process for making Ultramarine.

M. Gruinet of Thoulouse has succeeded in forming this valuable pig-
ment ; and our able correspondent. Professor Gmelin of Tubingen, has also
discovered a process for making it, which is given in the Ann, de Chim-
for April.

Prepare hydrate of silica and hydrate of alumina; the former is obtained by
fusing well powdered quartz with four times its weight of carbonate of potash,
dissolving the fused mass in water, and precipitating by muriatic acid
Hydrate of alumina is procured by precipitating a solution of alum with
ammonia. These two earths are to be carefully washed with distilled wa-
ter. After this, the quantity of dry earth remaining is to be ascertained,
by heating to redness a certain quantity of the moist precipitates. The
hydrate of silica which I employed in my experiments, contained in 100
parts 56, and the hydrate of alumina 3.21 parts of anhydrous earth.

Dissolve afterwards, with the assistance of heat, as much of this hydrate
of silica as a solution of caustic soda is capable of taking up, and deter-
mine the quantity dissolved. Take then for 72 parts of the latter (anhy-
drous silica) a quantity of hydrate of alumina, which contains 70 of anhy-
drous alumina : it is to be added to the solution of silica, and the mixture is
to be evaporated, with constant stirring, until a moist powder only remains.

This combination of silica, alumina, and soda, is the base of the ultra-
marine, which is to be coloured by sulphuret of sodium, and this is eflPect-
ed in the following manner: — Put into a Hessian crucible, provided with
a good cover, a mixture of two parts of sulphur, and one part of anhydrous
carbonate of soda ; it is to be gradually heated, until, at a moderate red
heat, the naass is well fused. This mixture is then to be projected, in very
small quantities at a time, into the middle of the fused mass. As soon as the
effervescence occasioned by the vapour of water ceases, a fresh portion is to
be thrown in. Having kept the crucible moderately red-hot for an hour, it
is to be taken from the fire and permitted to cool. It now contains ultra-
marine, mixed with sulphuret in excess, which is to be separated by water.
If there be sulphur in excess, it is to be expelled by a moderate heat. If
the whole of the ultramarine be not equally coloured, the finer parts may
be separated, after having reduced them to a very fine powder, by washing
with water.

7. Inventions for Sharpening Blades of Knives,

In 1827, Mr Felton took a patent for a method of sharpening edge-
tools by means of two ground steel cylinders, which acted like files. Their
edges were drawn backward and forward in the angle formed between the
two cylindrical files. The working surfaces are a succession of small
cylinders with openings between (bosses and recesses,) and the surfaces of
the bosses are exposed? or cut, or scribed round circularly, like the files

860 AncHysis of Scientific Books and Memoirs,

called floats, which present so many cutting or file edges, against which the
knife is pressed when drawn backwards and forwards.

Another patent has been taken out in May 1828 by Mr F. Westley, for
a similar apparatus, which is a decided copy of the principle of Mr Fel-
ton's invention, without being an improvement. It may, however, be
cheaper, and more easily made. It consists of four pairs of straight bars
of steel, with file edges, each pair being placed like a St Andrew's cross,
and at the same acute angle. The knife is then drawn between them as
in Mr Felton's contrivance. The inclination of the bars may be varied
with a screw.

Another method of effecting the same purpose has been invented by Mr
Blake of SheflSeld. A series of file-edged bars are connected together by
an axle passing through their centres, so that they can be set at any angle,
and fastened by a screw.

We have no doubt that a better contrivance than any of them would be
to use two ground surfaces of variable curvature, (parabolic, for example,)
so that various inclinations of the cutting surfaces could be obtained by
merely making the one revolve round upon the other.

8. Description of the Pneumatic Spoon. Invented by Mr Gibson.
This truly ingenious and useful invention has been very properly re-
warded by the Society of Arts with the Isis Medal. It is shown in Plate
II.Fig. 11, and has a lid L, opening round the joint, a b. Its handle H is a
tube, the extremity of which E, is a circular disc, upon which the opera-
tor puts his thumb. The fluid is introduced at the lid L ; and when the
lid L is shut, and the thumb placed upon E, the spoon may be held in any
position, without the fluid falling out. Hence it is especially valuable in
administering food or medicine when the patient is in bed. When the
spoon is inserted in the mouth, the food or medicine falls out of the spoon
by withdrawing the thumb from E.

Art. XXVII.— ANALYSIS OF SCIENTIFIC BOOKS AND ME-
MOIRS.

TTie Natural History of several New, Popular, and Diverting Living
Objects for the Microscope, with the phenomena presented by them under
observation^ 8^c. &;c. Conjoined with accurate Descriptions of the latest
improvements in the Diamond, Sapphire, Aplanatic, and Amician Micro-'
scopes ; and instructions for managing them, S^c. 6;c. To which is added
a Tract on the newly discovered Test Objects. Illustrated by very high'
ly finished Coloured Engravings, from drawings of the actual Living Sub-
jects. By C. R. Goring, M. D. and Andrew Pritchard. No. I.
Lond. Feb. 1829. Pp. 32. 2 8vo. Coloured Plates.
Iji a preceding article of this number (p. 327) we have already had oc-
sion to give an account of the labours of Dr Goring and Mr Pritchard re-
lative to the improvement of the microscope. Impressed as we are with the
high importance of this branch of science, and with the great value of the
improvements which these geiitltraen have introduced, we naturally looked

Dr Goring and Mr Pritchard's Treatise on the Microscope. 361

forward with the most sanguine expectations to the publication of the pre-
sent work. We knew well that both its authors were peculiarly fitted for
executing in a superior manner particular departments of such an exten-
sive undertaking ; but we were unable to anticipate how Dr Goring would
execiite the drawings of microscopic objects, or how Mr Pritchard would
discharge the functions of the naturalist. This information, however, is
amply supplied by the first number of the work ; and we have no hesita-
tion in stating it as our opmion, that Dr Goring and Mr Pritchard have both
accomplished these difficult tasks with the greatest success.

The first number, now before us, commences with an exordium or pre-
face, written in Dr Goring's peculiar but forcible style, and vindicat-
ing microscopic science from the sarcasms of ignorant and presumptuous
pretenders. The first chapter, which is also from the pen of Dr Goring,
contains practical remarks on Microscopes for viewing and drawing Aquatic
LarvcBt S^c. The other two chapters of the number, which are written by Mr
Pritchard, are entitled, 1. On the Larva and Pupa of a straw-coloured plum-
ed Culex or Gnat ; and 2. On the Larva and Chrysalis of the Ephemera
marginalis. The coloured drawings by Dr Goring, by which these two
chapters are illustrated, are executed in such a masterly manner, that they
will themselves bear to be seen by the microscope, and they cannot fail to
impress the observer with the conviction, that they are correct portraits of
the living animals.

The description of the larva and pupa of the plumed gnat will be interest-
ing to the naturalist.

" The transformation," says Mr Pritchard, " of this animal from the larva
to the pupa is one of the most singular and wonderful changes that can be
conceived ; and under the microscope presents to the admirer of nature a
most curious and interesting spectacle. Although the whole operation is
under the immediate inspection of the observer, yet so complete is the
change, that its former organization can scarcely be recognized in its new
state of existence.

" If we now compare the different parts of the larva with the pupa, we
remark a very striking change in the tail, which, in the previous state of
being, was composed of 22 beautifully plumed branches; while, in the
latter, it is converted into two fine membranous tissues ramified. This
change appears the more remarkable, as not the slightest resemblance can
be discovered between them ; nor can any vestiges of the former tail be
found in the water. The partial disappearance of the shell-like bodies is
another curious circumstance. The two lower of them, it may be conjec-
tured, go to form the new tail, for if the number of joints be counted from
the head, the new tail will be found appended to that joint which was
nearest them in the larva state. The two small horns which form the white
plumed antennai of this species of gnat, when in its perfect state, are dis-
cernible in the larva folded up under the skin near the head. The ali-
mentary canal appears nearly to vanish in the pupa, as in that state there
is no necessity for it, the insect then entirely abstaining from food ; while,
near this canal, the two intestinal blood-vessels seen in the larva hav^

362 Proceedings of Societies.

now become more distinct, and are supplied with several anastomosing
branches.

" During the latter part of the day on which the drawing was taken,
the rudiments of the legs of the perfect insect might be seen, folded
within that part which appears to be the head of the pupa ; and several of
the globules had vanished, those remaining longest that were situated
nearest the head. It may be necessary to observe, that the head of the
pupa floats just under the surface of the water; and the insect, in this
state, is nearly upright in that fluid, while the larva rests its belly or
sides at the bottom of the pond or vessel in which it is kept.

" The circuitous manner in which the Creator appears to form this species
of gnat, and many other of His smaller productions, is truly wonderful.
Other creatures are formed directly either from the egg or the maternal
womb. As, however, the Deity does nothing in vain, it may be presumed
that He must have had in view some important object in the preliminary
steps through which these beings have to pass, as from the egg to the
larva, chrysalis, and perfect insect ; and, however low these minutiae of na-
ture may be held in the estimation of the unthinking mass of mankind,
this most elaborate proceeding renders it not improbable that they may be
deemed by Him the choicest and most exquisite of His productions. These
mysterious creative operations of nature, as detected and unravelled by mi-
croscopes, are surely grand and capital subjects for observations. I should
pity the spirit of the man who scorned to be amused by inspecting these
marvellous metamorphoses, and disdained to be informed of the manner
in which they are effected."

From this specimen of Mr Pritchard's description, which is here seen
to great disadvantage from the want of the figures, the reader will form an
idea of the manner in which this part of the work will be executed.

Art. XXVHI.— proceedings OF SOCIETIES.
1. Proceedings of the Royal Society of Edinburgh.

December 15, 1828. — The following communication was read : " Ob-
servations on the Movements of the Molecules of Organized Bodies. By
Dr Brewster, F. R. SS. L. and E.

January 5, 1829. — The following Gentlemen were admitted ordinary
Members : —

Andrew Skene, Esq.

R. C. CoLYAR, Esq.

The following communications were read : —

1. Biographical notice of the late Sir J, E. Smith, P. L. S. with an es-
timate of the character and influence of his botanical labours, by the Rev.
E. B. Ramsay, B. A. F. R. S. E. and F. A. S. Scot.

- 2. Account of a great luminous arch as seen at Plymouth. By G. Har-
vey, Esq. F. R. SS. L. and E.

3. A letter from Dr Thomson describing a spontaneous emission of in-
flammable gas at Redly, seven miles N. E. of Glasgow.

Proceedings of the Royal Society, ^c. 363

' January 19. 1. Remarks on Glauchoma, by J. Howship, Esq. Mem-
ber of the Royal College of Surgeons. Communicated by Dr Knox,

2. Notice regarding a female Orang-outang sent from Singapore to Cal-
cutta to be kept with a male one in the possession of G. Swinton, Esq.
F.R.S.E.

February 2. 1. On the composition of Blende, by T. Thomson,
M. D. F. R. SS., L. and E. Professor of Chemistry, Glasgow.

2. Comparative experiments on different Dew point instruments, with a
description of one on an improved construction, by Mr J. Adie. Mr
Adie's improved instrument was exhibited.

February 16. — On the size of the brain and the proportion of its parts,
as affected by age, sex, or sexual mutilation. By Sir William Hamil-
ton, Bart.

March 2. — The following candidates were admitted Fellows of the So-
ciety : —

William Gibson-Craig, Esq.

Charles Fergusson, Esq. younger of Kilkerran.

James Ewing, Esq. LL. D. Glasgow.

Duncan Macneill, Esq. Sheriff-depute of Perth.

Reverend J. Sinclar, A- M. Pemb. Coll. Ox.

Arthur Connell, Esq.

Reverend J. Sheepshanks, A. M-

James Hope Vere, Esq. of CraigiehalL

The following communications were read : —

1. Notice of an experiment relative to the supposed spontaneous Motions
of Bodies suspended in Fluids, by Dr Brewster.

2. Notice regarding the Miners' Compass, and its application in under-
ground surveys, by R. Bald, Esq. Civil Engineer.

3. Notice concerning an autograph MS. by Sir I. Newton, found among
the papers of Dr D. Gregory, formerly Sav. Prof, of Astr, Oxford, by
Dr J. C. Gregory.

2. Proceedings of the Society for the Encouragement of the Useful Arts in

Scotland.

March 19, 1828. — Messrs George and James Nasmyth exhibited
and described a section model of the Steam Engine, constructed by them
for the purpose of explaining the principle and construction of that ma-
chine.

Messrs Nasmyth also exhibited, in action, an improved high Pressure
Steam Engine constructed by them.

Drawings of a Steam Carriage capable of carrying six persons were sub-
mitted to the Society, together with proposals for erecting the same by
subscription. By Messrs G. and J. Nasmyth.

April 2. — Notice of a machine for the use of boot and shoe-makers, in-
vented by Mr James Dowie, boot and shoemaker. Register Street, and
Mr Alexander Black, surveyor, Calton Street, Edinburgh, was read to
to the Society. The machine was exhibited in its full size; and a hand-
some model of it was also exhibited, and was presented to the Society along

364 ' Proceedings of Societies.

with the notice descriptive of its uses ; and a plan of a work-shop fitted up
in the most approved manner with these machines. By Mr James Dowie.

Mr Alexander Nasmyth exhibited and described a model of an im-
proved gate for agricultural and ornamental purposes.

Mr James Nasmyth exhibited and described a model of a method of
protecting chimney cans from the effect of wind.

Messrs G. and J. Nasmyth exhibited some experiments relative to the
cause of the coldness of high pressure steam when issuing from a small
aperture.

Mr RoBisoN exhibited some beautiful and delicate specimens of drill
turning.

Mr John Milne, architect, teacher of mechanical and architectural
drawing, Edinburgh, was elected an Associate Member.

April 22. — The following communications were made and models ex-
hibited, viz.

Drawings on a large scale of the great steam engine erected at Stoney-
hill in 1827, by Messrs Claud Girdwood, & Co. for draining the coal
mines of Sir John Hope of Craighall Bart, both in section and in perspec-
tive, and intended to be engraved by subscription, were exhibited to the
Society. By Mr John Milne.

A section drawing, and model of a double piston valve, proposed to be
substituted for the shde valve, particularly in working models of the steam
engine, whereby their cost will be greatly reduced and the waste of steam
prevented, were exhibited by Mr James Kilpatrick, Edinburgh.

An Attwood's machine, without friction rollers, constructed byMr Dunn,

optician, by which the application of friction rollers to that machine was

said to be unnecessary for even very delicate experiments, and the cost of

the instrument greatly reduced, was exhibited by Mr Dunn.

The following Gentlemen were elected Members :

Ordinary.

Charles M'Laren, Esq.

James Greig Junior, Esq. W. S.

John Craig, Esq.

John G, Kinnear, Esq.

May 7.— A new instrument for procuring an instantaneous light, invent-
ed by Mr John Napier, joiner. South Richmond Street, Edinburgh, was
exhibited and described.

Mr John Milne exhibited his drawings of the steam engine at Stoney-
hill, and read a description of them, which is intended to be pubUshed
along with the drawings.

Adam G. Ellis, Esq. W. S. was admitted an Ordinary Member.

Dec. 3. — The following communications were made :

A description of an Apparatus for sweeping Chimneys, invented by the
Rev. George Tough, Ayton Manse, was read, whereby the use of climb-
ing boys is rendered unnecessary.

A description of a clock pendulum, in which the impulse is received di-
rectly from the swing wheel, without the intervention of either fork or
verge, invented by Mr Alexander Doig, watchmaker Musselburgh^
was read, and a working model exhibited.

]

Proceedings of the Society of Arts for Scotland. 365

The following gentlemen were elected Members :

Ordinary.

Thomas Grainger, Esq. civil engineer, Edinburgh.

Robert Fraser, Esq. Newington, Edinburgh.

Associate*

James Smith, Esq. DeanstOun.

Dec. 17.— Mr Alexander Doig explained the nature and uses of his

clock pendulum without verge or fork, and again exhibited his working

model of it.

Captain Maconochie, R. N. exhibited and described very fully mo-
dels of a Steam Tug and Flat Boat, on new principles and construction, in-
vented by him.

Mr W. H. LiZARS read a letter from Mr Alexander Cowan, paper-
maker, Penicuick, sending him some specimens of paper made by him at
the request of Mr Lizars, from the masses of stuff from Nepaul, sent from
India by George S win ton, Esq. and exhibited to the Society (in mass)
upon the 5th of March last. Mr Lizars exhibited and presented to the
Society the specimens of this paper, which is of a bladdery kind, and does
not take a good impression from a copperplate. Mr Lizars also exhibited
and presented to the Society a specimen of copperplate printing on a piece
of Cobbetf.s Indian corn paper, which had been sent him by Mr Cowan.
The Indian corn paper takes rather a good impression from copperplate.

Mr John Milne was transferred from the list of associate to that of Or-
dinary Members.

January 7, 1829. — A description of a clock pendulum, which receives
the impulse directly from the swing wheel without the intervention of fork
or crutch, invented by Mr David Whitelaw, watchmaker, 16, Princes
Street, Edinburgh, was read, and the pendulum exhibited in action.

Mr Edward Sang read a paper regarding a new phenomenon discover-
ed in Iceland spar. Numerous specimens were exhibited in illustration.

January 21. — Mr James Gr^me, W. S., was admitted an Ordinary
Member.

Captain Maconochie, R. N., read a paper on steam-towing, demon-
strative of its application to General, but more particularly to Mercantile,
navigation ; and exhibited models in illustration, which he presented to
the Society.

A model of a door alarum by Mr James Forbes, Old Meldrum, was
next exhibited to the meeting, and a description of it read.

February 4. — Mr John Miller, civil-engineer, was elected an Ordinary
Member.

A new hydrometer, invented by the late Mr Lunan of Aberdeen, was
communicated by Mr John Armstrong, and exhibited and explained by
Mr Adie.

A description of a new door alarum, invented by Mr Robert Eraser,
Jeweller, Princes Street, was read, and a model exhibited and explained
by the inventor.

Mr Whitelaw submitted an enlarged description of his pendulum
without fork or verge, which was read.

866 Proceediiigs of Societies.

February 18.— Mr John Armstrong, Lauriston Place, was admitted
an Ordinary Member.

Mr John Adie read a paper on a new construction of a Dew Point In-
strument, accompanied with a comparative table of observations made by
it, and by others previously in use.

A model of the Rev. George Tough's apparatus for sweeping chim-
neys, whereby the use of climbing boys is rendered unnecessary, was exhi-
bited, and presented to the Society by the inventor.

March 4. — Mr Galbraith exhibited to the Society a Turnip Extractor,
invented by Mr William Hume of Greenlaw, and explained the manner
of its application for extracting turnips from the throats of cattle.

Mr Dunn read a paper on the escape of steam from the aperture of a

boiler, in reference to an experiment of Clement. Mr Dunn's experiments

- seemed to show in a very satisfactory manner, that no real danger can arise

from the singular adhesion of a circular disc to an aperture from which a

fluid is issuing.

3. Proceedings of the Cambridge Philosophical Society.

December 8, 1828. — The Rev. Professor Farish, Vice-President, being
in the chair, a communication was read to the society by the Rev. John
Warren of Jesus CollegCf stating the coincidence of the views respect-
ing the Algebraic Quantities commonly called Impossible Roots or Ima-
ginary Quantities, contained in his " Treatise on the Geometrical represen-
tation of the Square Roots of Negative Quantities," with those independ-
ently arrived at by M. Mourey, in hi* work entitled " La vraie Theorie
des Quantites Negatives et des Quantites pretendues Imaginaires," pub-
lished at Paris during the present year : and giving from these views a
proof, extracted from the work of M. Mourey, that every equation hqs as
many roots as it has dimensions.

A communication was likewise read by Dr Thackeray, respecting a
young woman in the neighbourhood of Cambridge, who was stated to have
lived without food or the least reduction in the weight of the body, since
the beginning of October.

The reading of Mr Challis's paper was also concluded, "on the exten-
sion to the satellites, of Bode's law of the distances of the primary planets."
The existence of the law in this case having been proved, it was inferred
that the distances may be approximately expressed in the following man-
ner : —

For the Planets 4, 4 + 3, 4+3 X 2, &c.

For Jupiter's satellites 7, 7 + 4, 7 + 4 X 2^, &c.

For Saturn's satellites 4, 4 + 1, 4 + 1 X 2, &c.

For Uranus's satellites 3, 3 + 1,3 + lXli^ &c.
It was likewise concluded from this law, that there can be no planet near-
er the sun than Mercury; and no satellite nearer the several primaries,
than the nearest of those, in each system which have been discovered.
The deviations from the law were also examined, and it was stated to be

Proceedings of the Cambridge Philosophical Society. 867

probably established that these depend on the masses and mutual actions
of the revolving bodies.

After the meeting, the Rev. L. Jenyns gave an account, illustrated by
drawings, of the comparative anatomy of birds and mammalia, and of se-
veral remarkable particulars respecting the former class of animals.

March 2, 1829. — The very Rev. the Dean of Ely in the chair. A me-
moir by Pierce Morton, Esq. of Trinity College, was read, " on ihe
focus of a conic section," in which the author pointed out the soHd con-
struction from which that point is derived.

The reading of a paper by Professor Whewell was also begun, " on
the application of mathematical reasoning to some of the theories of Poli-
tical Economy," in which the author maintained, that, so far as that science
is founded on definitions and axioms, the shortest and most certain me-
thod of deducing its results is by the assistance of mathematical process.

After the meeting, Professor Whewell gave an account of some of the
contrivances which have been employed in the use of the dipping needle,
and exhibited one of a construction in some respects new.

Art. XXIX.— scientific INTELLIGENCE.
I. NATURAL PHILOSOPHY.

ASTRONOMY.

1. Mr Dunlops Observations on Enckes Comet. — Mr Dunlop discovered
at Makerston the celebrated comet of Encke, on the 26th of October.
His first observation gave its place about 16" or 18" of time greater in
right ascension, and about one minute farther north than its place in the
Ephemeris. Several observations which he made in November, and which
he has reduced, give nearly the same differences, and the observation of
December 7th, gives its place about 20" greater in right ascension,
and fully one minute from the north in declination than the calculated
place. Since the beginning of December it has been decreasing in bright-
ness ; but it is considerably higher than it was in 1 822. Mr Dunlop
measured the diameter of the chevelure on the 7th December, and found
it about five minutes. About the end of November he thinks it would
be about six minutes. The nebulous form is not round but rather fan-
shaped, with the condensation of the nebulous matter near the point or
apparent lower extremity.

OPTICS.

2. Supernumerary Rainbows. — In our last Number , p. 163, we committed
a strange oversight in stating that the supernumerary colours had not before
been seen in the secondary or outer bow. We have ourselves mentioned
them in the article Optics, in the Edinburgh EncychpoBdia, as seen by M.
Dicquemarre, and also Dr Young's explanation, which connects the phe-
nomenon with that of the colours of thin plates, {^Nat. PhiU vol. i. p. 470,)
applies to both*

368 Acoustics — Electricity/ — Galvanism — Meteorology,

ACOUSTICS.

3. Velocity of Sound in the Arctic Reg-ions hy Captain Parri/s observa*
tions. — In a valuable paper by Professor Moll of Utrecht, (Phil. Trans-
1828, p. 103.) containing a reduction of Captain Parry's experiments on
the velocity of Sound at Port Bowen, the following table of results is
given : —

Velocity of sound in inches.
Captain Parry and Lieutenant Foster, 333.15

Do. another series, - - - 333.71

Do. another series, _ _ . 332.85

Professor Moll and Von Beck, - 332.05

M. Starapfer and Myrbach in Germany, 333,25

Messrs Arago, IMathieu, and Biot in France, 331.05
M. Benzenberg, Germany, - - 333.70

MM. Epinozd and Bauza in Chili, - 356.14

Dr O. Gregory in England, - - 335.14

French Academicians, - - 332.93

ELECTRICITY.

4. On the influence of Electricity on the emanation of Odours. — In a
late number of the Antologia of Florence, M. William Libri has announced
the following curious fact. ''^When a continued current of electricity tra-
verses an odoriferous body, camphor, for example, the odour of this body
becomes weaker and weaker, and finally disappears entirely. When this
happens, remove the body from all electrical influence, and put it in com-
munication with the ground, and it will continue without odour for some
time. The camphor will afterwards recover its properties gradually but
slowly." It would appear from a note in the Ann. de Chim. that difficul-
ties have occurred in the repetition of this experiment.

GALVANISM.

5. M. Becquerel on the temperature of conducting^ wires. — M. Becque-
rel has discovered that the temperature of a conducting wire communicat-
ing with the two poles of a pile, increases from each of its extremities, and
constantly reaches its maximum in the middle of the wire.

METEOROLOGY.

6. Mass of Meteoric Iron found in France. — On the 13th October, M.
Hericart de Thury read to the Institute a notice of a mass of meteoric iron
existing at Caille, in the department of the Var. In August last, Mr
Brard sent from Frejus a specimen of the mass in question, with respect
to the origin of which he did not decide. The examination made by the
author caused him to suspect that it might be meteoric iron, and he there-
fore wrote to M. Brard, to beg that he would go to the place, in order to
determine the nature of the mountain on which it was discovered ; to ex-
amine the mass of supposed meteoric iron ; and to collect from the inhabi-
tants all the information which they could give him. The following is
extracted from the account given by Mr Brard : — The mass of iron which

Chemistry, 36^9

had been for two years placed at the door of the church at Caille, has
been in that village about 150 years. It was discovered in the mountains
of Audehert, a league off, and was drawn by four oxen into a court or gar-
den in the village, where it seems to have been forgotten ; but an inhabi-
tant having inclosed it in a wall, it was claimed as an object held in some
veneration ; the wall was pulled down by the authorities, and the enor-
mous mass was deposited in the principal street of the village, from which
it was removed to the spot which it now occupies.

The form of the mass is very irregular ; its external colour blackish
brown, with a shade of lead colour ; it is shining, but occasionally spotted
with yellow rust ; its internal colour is whiter than that of common iron.
It weighs about 1000 or 1200 pounds.

The mountain in which this mass was found is of considerable altitude,
and similar to those which surround it ; there are no appearances of iron
works having ever existed in the neighbourhood.

This iron has the crystalline appearance which marks its meteoric ori-
gin, and Mr Laugier has found that it contains nickel.

Application has been made for its removal to Paris, and this has pro-
bably been already accomplished.

It was reported in the village, that two smaller masses were found with
it, which were used for making horses' shoes, nails, &c. It was also pro-
posed to heat this mass, and thus divide it, and apply it to the same pur-
poses ; fortunately for the interests of science, the greatness of the mBss
prevented the intended destruction. — Le Globe, Phil. Mag.

At the sitting of the Academy of Sciences of the 17th November, the
minister of the interior announced, that, at the request of the academy, he
had destined the sum of 610 francs for the purchase of the above mass of
meteoric iron, and for its transport to the Museum of Natural History.

II. CHEMISTEY.

7. Diamonds made artificially in France — On the 10th November M.
Arago communicated a note from M. Cagnard de Latour, in which this
philosopher announces that he has succeeded in crystallizing carbon to form
the diamond, by methods different from those. of M. Gannal, and that a
sealed packet deposited in the secretariat in 1824 contains the details of
his first processes.

M. Arago announces that he knows another person who has arrived at
similar results ; and M. Gay-Lussac declares, that M. Gannal spoke to
him more than eight years ago of his attempt.

At the meeting of the Institute of 17th November M. Thenard gave
an account of his examination of the products obtained by M. Cagnard de
Latour in his crystallization of carbon. Such of the crystals as have no
colour scratch quartz, but they are scratched by diamond. They do not
burn ; and an accurate analysis has proved that they are not carbon, but
a silicate. We trust that an equally careful examination will be made of
the diamonds of M. Gannal, and those of the persons, more than one,
whom M. Arago mentions as having obtained similar products*

VOL. X. NO. II. APRIL 1829- A a

3T[0 Scientific Intelligence, *

8. Meliing point of Silver and its alloys with Gold, — Mr Prinsep of Be-
nares, in a very able paper on the measurement of high temperatures, has
given the following average results, which are of great importance :—

Full red heat, - - ^200° Fahr.

Orange heat, - - 1650

Silver melting, - - 1830

Silver with one-tenth gold, 1920

Silver with one- tenth gold, 2050

Mr Wedgewood made the melting point of silver so high as 471?° and
Mr Daniell 2233°.

III. NATURAL HISTOEY.

MINERALOGY.

9. Specimen of Chalcedony with a large Fluid Cavity. — A foreign dealer
in minerals has sent us a drawing of a very curious specimen of common
blue chalcedony, having in it a cavity half full of a " limpid fluid not un-
like to water." The specimen has been ground and polished all round the
cavity, so as to leave a crust of chalcedony about one-tenth of an inch
thick. The external dimensions of the specimen are two inches long by
one inch broad, so that the length of the cavity is at least one inch and se-
ven-tenths. The price asked for this specimen is thirty guineas. If the
fluid is water, it is not worth the tenth part of that sum ; but if it is,
which is not probable, one of the new fluids discovered in topaz, the spe-
cimen would be invaluable.

10. Analysis of Radiolite. By Professor Hunefeld.

Silica,

Alumina,

Soda,

Potash,

Water,

Oxide of iron.

Carbonate of lime.

Matrix,

41.88

23.79

14.07

1.01

10.00

0.91

2.50

5.50

00 fifl

11. Analysis of Iron Sinter from Freiberg,

r M. K.KERSTEN.

Arsenic acid.
Oxide of iron.
Water,

30.25
40.45
28.50

00 <^n

12. Analysis of Datholite from the Harz.

Dr Dv Me NIL.

Lime,
SiUca,

Boracic acid.
Water,

35.59

38.51

21.34

4.60

Mineralogy — Geology. 371

13. Analysis of Marmolite from New Jersey. By Mr Thomas Steel,

ji Pupil of Dr Thomson's.
Silica, - - 41.256

Magnesia, - - 41.720

Alumina, - - 1.000

Peroxide of iron, - 0.400

Water, - - 17.680

102.056

Hence Dr Thomson considers it a hydrous sesquisilicate of magnesia,
or a variety of the precious serpentine or picrolite of Haussmann. Mr
Nuttal, the discoverer of the mineral, found no alumina, and made the
silica and the magnesia 36 and 46.

14. Analysis of Bismuth blende of Breithaupt. By Professor Hunefeld.

Carbonate of bismuth, - 58.8

Arsenic acid, - - 2.2

Silica, - - - 23.8

Arseniate of cobalt, copper and iron, 5.9
Matrix, . - - 9.1

99.8

15. Analysis of Leelite. By Mr R. Mitchell, a Pupil of Dr Thomson's.

Mr Mitchell.

Dr Clark.

Silica,

81.91

75.0

Alumina,

6.55

22.0

Protoxide of iron.

6.42

Potash,

8.88

— — ■

Manganese,

2.5

Water,

0.5

103.76

100

Hence it consists of 2 atoms octosilicate of alumina,

I atom octosilicate

of iron, and I atom octosilicate of potash.

GEOLOGY.

16. Conclusion of the General Summary of the Geology of India, By
James Calder, Esq. From p. 184 of this volume. — " At Bancora," says
Mr Calder," the calcareous concretion called kunkur begins to cover the sur-
face of the granite and mica schists. Thence we pass on to the great coal
field that occupies both sides of the river Dummoda. The boundaries of
this formation have not yet been accurately ascertained ; to the southward
we trace its associating rocks (sandstone and shales) to within a few miles
of Rogonauthpore, reposing on granite. About forty miles north by east
from that place, we come to the first colliery ever opened in India. The
late Mr Jones, an enterprizing and laborious engineer, had the merit of
commencing these works in 1815, at a place called Rany Gunge, on the left
bank of the Dummoda. It is described as the N. W. coal district of Ben-
gal. Mr Jones observed the line of bearing for sixty-five miles in one di-
rection, its breadth towards Bancora (on the S. W. side) being not more
than eleven or twelve miles from the river ; and he conjectures that the
same coal formation, crossing the valley of the Ganges near Cutwa, unites
with that of Sylhet and Cachar, which he denominates the N. E. coal dis-
trict, and from which abundant specimens of coal have been produced.

372 Scientific Intelligence.

An accurate survey of these extensive and valuable deposits seems to be
called for, by obvious considerations of the most important public advantage.
*' The principal rocks that compose this formation are varieties of sand-
stone, clay slates, and shales, with occasional dikes and veins of trap and
green-stone ; the shale immediately covering the coal abounds with vege-
table impressions, and some animal organic remains ; amongst these Dr
Voysey distinguished a phytolithuSy a calamite, lycopodium, and one speci-
men of a gigantic species of paletia. The shale passes into clay-slate, above
which succeeds a soft, but gritty, micaceous yellowish-grey sandstone, here
and there becoming indurated and slaty. This forms the surface rock all
over the coal district, rising into low round-topped hills and undulated
grounds. On the coal pits, (three in number), which have yet been sunk
to a depth of only eighty-eight feet, seven seams of coal have been met
with, one of which exceeds nine feet in thickness ; the quality of the coal
has proved excellent, resembling the Sunderland coal, but leaving a larger
proportion of cinders and ashes.

" Proceeding northward and westward from Bancora and the Dummoda
river, the road to Benares passes over granitic rocks, of which the ranges
of hills on the left, and the whole country as far as the Soane, and round
Skeergatty and Gya, is probably composed. On approaching the Soane
river, crossing the hills behind Sasseram, sandstone begins to appear, and
continues to be the surface rock, with probably only one considerable in-
terval all the way to Agra, forming, as before noticed, the southern barrier
of the valley of the Ganges and Jumna. That interval occurs in the low
lands of Bundlecund, where the remarkable isolated hills, forming ridges
running S. W. and N. E., are all granitic, the high lands being covered
with sandy stones. This brings us back to the rocky plains of Hindoo-
stan, and to the last of the three principal mountain ranges first alluded
to; viz. the Vindya Zone, which,crossing the continent from east to west,
may be said to unite the northern extremities of the two great ranges al-
ready described, which terminate in nearly the same parallel of latitude,
forming, as it were, the base of the triangle that elevates the table-land
of the peninsula. The Vindya belt, yielding little in classical character to

, the Himalaya, intersects the heart of the country, and is distinctly trace-
able, even in our very imperfect maps, running south 75° west, from the
point called the Ramgurh hills towards Guzerat. This great zone has nu-
merous divisions, and a multitude of names, almost every district giving a
change of denomination ; but to the eye of a geologist, who considers things
on an extended scale, there is a parallelism in the disjoined parts, and a
general connection and dependence on the central range. The substrata
prove this fact, for in every case they preserve a parallelism to it. The great
surface formations of Central India and the Deccan are granite, sandstone,
and the overlying rocks, the latter exceeding in their extent those of any
other country. The basaltic trap formation extends northward all over
Malwa and Sanger, Sohagpore, and Omercantoe; thence, proceeding south-
ward by Nagpore, it sweeps the western confines of Hydrabad, nearly to
the 15th parallel of latitude, and, bending to N. W., connects with the sea
pear Fort Victoria, as already noticed, composing the shores of the Con-

Geology. 373

can northward, all the way to the mouth of the Nerhudda, covering an
area of at least 200,000 square miles. It overlies sandstone in the dis-
trict of Sagur, and hence it may be inferred, that a portion of it, at least,
is posterior to sandstone. It possesses the common property of trap rocks
in general, viz. that of changing the nature of every other rock which
comes in contact with it; and in the district of Sagur it is always associa-
ted with an earthy lime-stone, which seems to have undergone calcination,
exhibiting strongly the marks of the agency of heat. According to Capt.
Franklin, the sandstone deposits are so very regular, both in their dispo-
sition and geological character, that they cannot be mistaken ; their gene-
ral parallelism to the horizon, and their saliferous nature, appear to him
to identify them with the new red sandstone of England; whilst the red
marie and its superincumbent variegated or mottled variety (called by Wer-
ner hunter- sand-stein), together with the deposits of lias limestone, place
the matter beyond all doubt. In using the term ' new red sandstone,'
however, it must be understood, as it is in England, to comprise all that
series of beds which intervenes between the ^m*and mag-nesian limestones;
admitting which, he concludes with confidence, that the waterfalls of the
Bundachel hills of Bundlecund, which are the lowest steps of the Vindya
range, will afford a series of formation corresponding perfectly with those
of England, where the lias formation has been thoroughly studied, from
its connection with the coal measures.

" On the western side of India it is, as we have seen, covered by overlying
rocks, as at Sagur ; it appears, however, flanking the large primitive branch,
which runs to Odeypore, on the side of Guzerat, and to the north it sweeps
into the desert to an unknown extent. The paper in^he London Geologi-
cal Transactions, proves this fact, even if we had not the more substan-
tial evidence of rock-salt, which is there produced in abundance.

'"' The next of the great surface rocks of Central India is large-grained
granite, frequently passing into gneiss, generally composed of quartz, flesh-
coloured felspar, a little brown or black mica, and hornblende. It varies,
however, in appearance, and also in the proportion of its constituents.

** With regard to th^rocks of more recent formation than sandstone, In-
dia is peculiarly barren ; but this circumstance, above all others, renders
its geology interesting, if it be in reality so. Whence, says Mr Calder,
does such a remarkable distinction proceed ? The reply may comprehend
a solution of the most important phenomena of the science.

" The lias formation is, as yet, known only from Capt. Franklin's re-
searches. He has found it in Bundlecund in situ, reposing on red marie,
or new red sandstone, and its geological character is, in all respects, so dis-
tinct that it cannot be mistaken. He thinks he has identified it by its
characteristic organic fossil, — the gryphite, — by stems of fern and fossil
wood ; and, moreover, the lime made from it possesses the peculiar pro-
perty of the species, and its finer varieties have been found to answer for
lithography. He entertains no doubt of the existence of this formation,
nor of its proving two main points: first, that the sandstones on which it
reposes is the red marie, or new red stone of the English school ; and se-
cond, that, with the exception perhaps of trap, and the concretionary for-

S74 Scientific Intelligence.

mations, it is the most recent hitherto discovered in India ; for Capt. Frank-
lin has subsequently traversed the range at the foot of which it extends,
and has found no traces of an oolitic formation, and thinks it obvious, that,
if such a formation does exist in India, it ought to be found there.

" Common kunkur, on analysis, is found to contain the elements of
oolite and chalk. May not this concretionary formation, therefore, which
seems peculiar to India, be the remains of what, under different circum-
stances, might have become (as in England) regular oolitic strata ? Capt.
Franklin observes, that these irregular beds of kunkur, which are found
following every water-course, and forming its banks, have all the appear-
ance of having been deposited under circumstances peculiarly unfavourable
to regularity ; and it may be asked to what agency, but that of running
and turbulent water, can such appearance be satisfactorily ascribed ?

" With regard to organic remains (the most interesting of all the bran-
ches of geological science), it is to be feared that India is not likely to prove
a productive field. The coal strata, when public spirit and enterprize
shall excavate them, will probably afford other varieties of vegetables and
fishes, besides those already mentioned ; and the lias limestone may con-
tain specimens of the sauri tribe ; but hitherto, the most striking feature
in Indian geology is the almost total absence of organic remains in the
stratified rocks, and in the diluvial soil.

" Silicified wood has been found in the diluvium of Calcutta and Jub-
bulpore; but bones of animals have never yet, we believe, been discovered,
either in diluvium or in stratified rocks ; in this branch, however, the ex-
tensive deposits of fossil bones recently discovered in Ava, apparently ante-
diluvian, and, perhaps, the yet unexplored caverns in the limestone strata
of Sylhet, Cachar, and Assam, promise a fruitful field for future researches.

" Mr Calder concludes his observations by introducing a view of the
system of Indian geology adopted by the late Dr Voysey, as communicated
in some of his last letters to his lamented friend Dr Abel ; and, as they
contain almost the only record he has left us of the general conclusions to
which his philosophic mind came, and it is desirable to preserve every ray
of light from so valuable a source, to guide our future research, the follow-
ing extracts are transcribed verbatim from his letters.

" On the 1st of August 1823 he writes as follows : — ' It may appear ra-
ther presumptuous in me to attempt a sketch of Indian geology after so
short a residence, particularly when you recollect that Smith's map of Eng-
lish geology took him twenty years to complete. There is, however, this
remarkable difference between the two countries, that in India, instead of
twenty different formations, as in England, there are only four, viz. the
granitic, the sandstone, the clay-slate, the trap, the diluvial. All of these
have subordinate rocks : but they are never found in any of the other for-
mations, and they all occupy a vast extent of surface.'

" In a subsequent letter, of the Hth September 1823, he gives the following
synopsis of Indian geology, between the parallels of 27° and 28° north lati-
tude, viz. : * The geology of India may be divided into four formations
roch of which ]wssessing characteristics in common, which strongly mark
tlieir contemporaniety.

Geology. 375

" * \. The granitic rocks include — granite, to which is subordinate cubic
quartz-rock, greenstone, in veins and beds ; gneiss, to which is subordi-
nate hornblende slate, crystalline limestone, crystalline dolomite, mica-slate
chlorite, talc-slate, and quartz-rock.

" ' 2. The schistose rocks include sandstone, crystalline, conglomerate
and cemented, which passes into clay-slate, calcareous clay-slate, and cal-
careous-slate, to which are subordinate, Jlinty slate^ diamond breccia, and
coal measures.

" ' 3. The basaltic, or overlying, and intruding rocks, include basalt,
wacken, amygdaloid, iron-clay or lacterite, which is sometimes directly
superimposed on granite and gneiss.

" ' 4. The diluvian lands or plains, black soil from the debris of trap
rocks. Diluvium of the Doab, and plains of the Ganges, including the
beds of calcareous conglomerate, or kunkur.'

'* He then proceeds. — ' I am convinced that very few additions will be
made to my synopsis. There is nothing in India resembling the oolite, the
chalk, or the London clay. Up to the present period, I am inclined to
think that both the granite and gneiss of India are contemporaneous, as
they are perpetually passing into each other, and have the same subordi-
nate rocks ; I think it probable they owe their difference of structure to a
different mode of consolidation. At present, also, I am disposed to think
that the stratified rocks are the oldest in point of time ; but I will not an-
ticipate: the antique history of India and geology are intimately connected
in the history of the trap rocks, as exemplified in the tradition of towns
having been overwhelmed by showers of black mud. Lately reading an
account of Sclotthiem's discovery of human bones, he says that they were
always calcined, and deprived of their animal gluten. Does he mean to'^
say that they had lost their carbonic acid ? Do you think that if India
"was inhabited before the deluge, there would not have been some remains
of animals in its vast and numerous diluvial plains ? It has been a favourite
speculation with some philosophers that the aborigines of India, the Goands
(who differ most remarkably in their manners and customs from the Hin-
doos,) escaped from the waters of the deluge on the high mountains in the
interior. There appears to me to be a great resemblance in the animal and
vegetable productions all over India. I do not think that I have seen any
thing which you have not got in the vicinity of Calcutta.'

" In another letter, dated 22d February 1824, he says : — * I am making
a barometrical section and geological sketch of the country as I proceed,
and shall have, by the time I reach Calcutta, made a great addition to the
geological map of India. I have been struck, during my travels in India,
by the great sameness of the productions, that is to say, of the same soil.
If I were told such is the soil of A, I think I could tell exactly the mode
of cultivation, the grain or produce, the fauna and the sylva. This is, no
doubt, owing to the fewness of the formations and their great extent. Ever
since I left Sumbhulpoor I have been travelling on gneiss, which passes
into granite with the usual trap veins of that formation in India ; also
into mica-schist, containing beds and veins of hornblende-rock and horn-
blende-schist and quartz rock ; the mica-schist passes into chlorite-schist.''
—Cal. Gov. Gaz.

376 List of Scottish Patents.

17. M. RaspaiVs Discovery respecting Belemnites. — M. Raspail has lately
announced to the Institute, that, after a careful study of 250 Belemnites
collected in the mountains of Provence, he has discovered that Belemnites
are not the shells of animals, as geologists generally think, but that they
are cutaneous appendages belonging to marine animals, allied to the Echino-
dermata, but which are now extinct.

Art. XXX.—LIST OF PATENTS GRANTED IN SCOTLAND
SINCE DECEMBER 6, 1828.

33. December 6. For an Improvement in the Manufacture of Buttons
and in the Machinery or Apparatus for Manufacturing the same. To
Thomas Tyndall, county of Warwick.

34. December 12. For an Improvement in the making of Alum. To
William Strachan, county of Denbigh.

35. December 24. For certain Improvements in Distillation. To Robert
Stein, county of Middlesex.

36. December 24. For a Method or principle or an^apparatus for Raising
Water or other Fluids. To Anton Bernhard, county of Middlesex.

1. 1829. January 19. For an Improvement in the Construction of Ships'
cable and hawser chains. To John Hawks, county of Middlesex.

2. January 26. For an Improvement or Improvements on Bits. To
Valentine I^lanos, county of Middlesex.

3. February 26. For certain Improvements in the construction of Steam
Engines and Steam Generators or Boilers. To Samuel Clegg, county of
Lancaster.

4. March 5. For certain Improvements in Machinery to be used in Na-
vigation, applicable to the Propelling of Ships and other Floating Bo-
dies, &c. To Charles Harsleben, county of Middlesex.

Art. XXXI.— CELESTIAL PHENOxMENA,
From April 1st, to Jtdy 1st, 1829. Adapted to the Meridian of GreeU'
wichj Apparent Time, excepting the Eclipses of Jupiter s Satellites which
are given in Mean Time.

N. B. — The day begins at noon, and the conjunctions of the Moon and
Stars are given in Right scension.
APRIL.

D. H. M. S.

1 2 5 (^4*05

3 The sun will be eclipsed invisible at
Greenwich.
The conjunction is at lOh 21|' in
long. OS 13° 63f'. })'s lut. 35^'
S. The Sun will be centrally
eclipsed on the meridian at 9^ 564'
in W. Long. 149° 6^', and S. Lat.
32' 15'.

3 10 21 % New Moon.

7 4 60 49 ]) c5 Aldeb. ]) 54' N.

D. H. M. S.

8 13 17 52 Em. III. Sat. ^

8 14 12 20 Im. H. Sat. IJ.

9 13 6 43 Im. I. Sat. 7/

9 16 ^ d A a

10 14 7 5 First Quarter.

12 6 11 58 p d 2<t ss D 43' N.

13 13 59 43 5 3 ^ ^ ]) 30' N.
15 14 54 Im. III. Sat. Ij.

15 20 ? d ^ K

16 15 0 25 Im. I. Sat. U

16 23 r^ d 2 * tt

17 13 45 ba©

Celestial Phetwmena^ April — July 1829*

377

D.
18
19 21

H. M.
18 22

22
26
26

55
30

15 8

J3 16

19 57

11 8
0

9 20

9 50

14 51

13 45

13 59

9 15 10

7 36

10 11 39
10 13 41
II

18 11 33
20 8 15

20 21 31

21 10 45
25 8 19

31
48

25 13 27

Full Moon,
enters b

6» K

Last Quarter.
□ 0

MAY.

34 ]) c3 0 K D 45' S.

39 Im. I. Sat. 7/
^ New Moon.

23 Im. II. Sat If.

52 ]) c5 1 -^ « D 24' S.
21 ^ 6 2 <r b ]) 16' s.
17 p c5 Aldeb. 5 58' N.

9 Sup. c^ 0
32 I (^ 2 « gs ]) 51' N.

40 Im. I. Sat. 1J.

]) First Quarter.
57 J (5 0 ^ ]) 7' N.

49 Im. II. Sat. 7/

f Stationary.
6A «
^ d 132 «
02» b
23 ]) c5 9 =^ }) 30' N.

O Full Moon.
19 Im. I. Sat. 11
Sup. 6 0
_ enters II
6 Im. III. Sat. y
^ Last Quarter.

35 Im. 1. Sat. "J/

D.
26
28
28

14
9
14

5
12

8
12
13
17

6 14

7 5

10 13
I 9

2
43

49
0

52
22
23

54
21

19 10

20 9

21 6

21 8
22

23 12

24 14
26 12

29 10

30 16

8
3

57
28
12

9 6 132 b
38 ]) d r K }) 62' S,
16 Im. in. Sat. IJ.

JUNE.

% New Moon.
4 Em. I. Sat. 9/

c?d«n
^d«n

42 Em. II. Sat. 9/

43 I d e a ]) 27' S.
52 » d 'T ^ j) 51' N.

]) First Quarter.

? d 132 d
37 Em. I. Sat. 7/
29 ^ d 9 T1]P ]) 47' S.

d«^n

d > =2= ]) 39' S.
d <? Oph. D 47' S.
Full Moon.

. 6fiYS) ii'S.

56 Em. I. Sat. 2/

2d.n ^

0 enters 25

52 ^ d fl.OS )) 1' S.

d Stationary.

(J[ Last Quarter.
6 D d r K )) 65' S.
43 Em. I. Sat ?/

?dJ^n

10 ]) c5 Aldeb. }) 57' N.
12 Em. n Sat %
A New Moon.

Mercury.

» h. '

1 22 24

7 22 32

13 22 43

19 22 57

25 23 14

Times of the Planets passing the Meridian.
APRIL.

Venus

h '

23 16

23 21

23 26

23 32

23 37

Mars. Jupiter. Saturn. Georgian.

48
43
38
33

h '

10 12

15 49

15 27

15 3

14 39

15
53
32

6 11
5 49

h
19
19
19
18
18

48
27
6
43
22

1 23 36

7 24 2

13 0 26

19 0 55

25 1 19

13
19
25

38
45

1 42
1 28

23 42

23 48

23 54

0 0

0 b

13
21

0 28
0 35
0 45

MAY.
2 22
2 16
2 10
2 3

1 56

JUNE.

1 48

1 40

1 32

1 24

1 16

14 14

13 49

13 23

12 56

12 29

11 57

11 29

11 I

10 33

10 6

5 28

5 7

4 45

4 23

4 2

3 36

3 14

2 52

2 30

2 8

59
36
13
49
26

56
37
8
37
18

37S Mr Marshall's Meteorological Observations

Declination of the Planets*

APRIL.

Mercury.

Venus.

o /

Mars.

o /

Jupiter.

Saium.

o /

Georgian.

8 6S.

1 55 S.

19 49N.

51 S.

21 12N.

25 S.

5 28

1 3N.

20 47

21 U

2 4S.

'4 1

21 39

21 10

2 ON.

C 56

22 24

21 8

6 37

9 46

23 3

21 6

MAY.

11 35 N.

12 26N.

23 35N.

41 S.

21 IN.

16 33

14 67

23 59

20 57

20 62

17 15

24 17

20 62

23 55

19 16

24 27

20 46

25 25

20 59

24 30

20 40

JUNE.

25 29N.

22 33N.

24 25N.

15S.

20 32N.

20 S.

24 30

23 29

24 13

20 24

22 57

24 0

23 54

20 16

21 13

24 5

23 28

20 58

20 7

19 37

23 45

22 56

20 53

19 57

The preceding numbers will enable any person to find the positions of
the planets, to lay them down upon a celestial globe, and to determine their
times of rising and setting.

Art. XXXII. — Summary of Meteorological Observations made at Kendal
in December 1828, and January and. February 1829. By Mr Samuel
Marshall. Communicated by the Author.
State of the Bathometer y Thermometer, &;c. in Kendal for December 1828.

Barometer. Inches.

Maximum on the 14th, ... 30.27

Minimum on the 7th, ... - 28,99

Mean height, - - - . 29.64

Thermometer.
Maximum on the 13th and 14th, ... 52.5°

Minimum on the 9th, - - - - ' 31°

Mean height, ... - . 44.20*

Quantity of rain, 9.226 inches.
Number of rainy days, 25.
Prevalent wind, west.
In this month, as in the last, there have been but two nights of frost,
the thermometer never having been, but in those instances, at or below the
freezing point. It is rarely found that the mean temperature of Decem-
ber is upwards of 41°. A greater quantity of rain has fallen in this month
than in any preceding one in the year, and yet, though the weather has
been with little variation rainy, the barometer has varied less than is often
the case when the weather is more variable. The wind has been in the
west for 17 days, and rain has generally accompanied it. For the rest of
the month winds have prevailed from the S.W. and S. excepting one day.

made at Kendal in Dec^ Jan. and Feb. 1829. 379

but we have had occasional currents from other points of the compass,
though of short duration.

January.

Barometer. Inches.

Maximum on the 7th, - - - 30.06

Minimum on the 26th, - - - 28.83

Mean height, - - 29.68

Thermometer.
Maximum on the 1st, - ' - - - 47"

Minimum on the 20th, . - - - 18.5**

Mean height, - - - - 32.18°

Quantity of rain, 0.747 inch. ^

M umber of rainy days, 3.
Prevalent wind, north.
This has been a remarkably fine winter month. No rain fell from the
4th to the 28th, and though during that period we had some snow, this
was confined chiefly to the 23d, 24th, and 25th. On the 26th was a thaw,
and on the 27th, .090 inch of water was taken by the guage, which was
the melted snow that had fallen the three preceding days. The barome-
ter has been very variable. A corona was observed several times round
the moon, but no halo. Neither has Aurora Borealis been observed during
the month, (though frequent attention has been paid to the subject,)
excepting on the evening of the 2d, when it was very bright. The three
days on which rain was taken were the 1st, 4th and 28th. Since the 2d,
the nights have mostly been frosty, and sometimes the greater part of the
days. There has not been registered in Kendal, for the last seven years
so small quantity of rain in January.

February.

Barometer. Inches.

Maximum on the 2d, - - . 30.33

Minimum on the 2 1st - - - 29.10

Mean height, ... 29.88

Thermometer.
Maximum on the 13th and 16th, - - 60°

Minimum on the 3d, . _ . . 23°

Mean height, - - . . 38.08o

Quantity of rain, 1.234 inch
Number of rainy days, 11.
Prevalent wind, west.
There has been much less frost in this month than in the last, and yet
there has been but little rain, though the weather has been mostly cloudy.
In January and February last year there were 32 rainy days, and 10.817
inches of rain were taken, but in those months in the present year there
have been but 14 rainy days, and 1.981 inch of rain. The barometer has
been mostly high, and the mean for the month is greater than that of any
month in the last year. Both this and the last month have been colder
than the corresponding ones in 1828. The wind has been prevalent in
the west for 15 days.

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INDBX TO VOL. X.

Adam, Dr, on the Mantis tribe of in-
sects, 351
Adie, Mr A. MeteorologicalJoumal, 192
-^tna, Mount, on the eruptions of, 310—

on the large chestnut of, 314
Anchors, remarks on their formation, 220
Arch, luminous, on a splendid one at
Plymouth, 146 — at Chesfield Lodge,
177— at Islay-house, 177 — at Edin-
burgh, 177— at Perth, 179
Aurora borealis at Perth, 179

Barometer, account of Dr WoUaston's
differential one, 356

Becquerel, M. on the properties of the
Tourmaline, 51 — on the temperature of
conducting wires, 368

Belemnites, their origin discovered, 376

Berlin, account of the great congress of
Philosophers at, 225

Berthier, M. his description of nontronite,
a new mineral, 150

Birds, experiments on the ears of, 353

Bismuth blende, analysis of, 371

Blackburn, Rev. Mr, on a new sound-
ing board for a church, 357

Blue colour, process for making a fine one,
358

Bombay, mean temperature of, 17— on
- the rain at do., 141

Bottles immersed in the sea, experiments
on them, 144

Braconnot, M. his process for making a
fine blue colour, 358

Brewster, Dr, on two remarkable rain-
bows, 163---on the motions of the mo-
lecules of bodies, 215 — on a singular
property in glauberite, 329— on dia-
mond and sapphire lenses, 327 — ob-
servation on tables of refractive pow-
ers, 298

Bustamente, Don Jose Maria, on a new
gravimeter, 207

Calder, James, Esq., on the geology of
India, 181, 371 — on a singular species
of mollusca, 352

Cambridge Philosophical Society, pro-
ceedings of, 1 74, 366

Cassia, oil of, experiments on the cause
of its high dispersive power, 308

Cast iron, on its permanent increase of
bulk, 356

Celestial phenomena, 188, 376

Chalcedony with a large fluid cavity, 370

Chestnut tree of Mount iEtna, on the
large one, 314

ChrysoHte in obsidian, first discovered by
Professor Del Rio, 206

Clouds, on a curious formation of, 33

Comet, Encke's, rediscovered, 175 — its
elements continued, 175 — comet of
September 1827, 176

Congress of philosophers at Berlin, 225

Contributions to physical geography, 310

Copper, metallic, on the quantity raised
in Britain, 180

Cornwall, on the steam engines of, 34—
quarterly notice of their performance,
137, 213

Datholite, analysis of, 370

De Witt, Mr, on the variations of the
magnetic needle, 22

Diamond lenses for microscopes, 327

Diamonds, artificial ones supposed to be
made in France, 369

Double stars in the southern hemisphere,
301

Drummond, Dr, on the motions of the
molecules of bodies, 215

Dunlop, James, Esq. on remarkable ne-
bulae and clusters of southern stars,
282 — on double southern stars, 301—
on Encke's >omet, 367

Electrical conducting power of fluids, 179

Encke's comet, 175

Eye, on its insensibility to particular co-
lours, 153

Falmouth, on mean temperature of, 178

Flourens, M., on the ears of birds, 353

Foerstemann's experiments on the con-
duction of voltaic electricity by fluids,
179

Forbes, J. D. Esq., his physical notices
on the Bay of Naples, 109, 245 — on
a new self-registering thermometer,
159 — on the defects of the sympieso-
raeter for measuring heights, 334

Funchal, meteorological journal kept at,
73

Gas, inflammable, on boring for salt, 186

Geography physical, contributions to, 310

Geology of India, summary of the, 181,
371

Gerard, Captain Patrick, his meteorolo-
gical register at Kotgurh, 139

Gilbert Davies, Esq., P. R. S., his be-
quest to science, 186

382

INDEX.

Glauberite, on a remarkable property of,
329

Goring, Dr, his improvements on the
microscope, 327 — his work on the mi-
croscope analysed, 360

Grant, Dr R. E., on the influence of
light on the motions of infusoria, 346
— on the generation of the Virgularia
mirabilis, 350

Granules from an exploded graiji of Pol-
len, 97

Gravimeter, on a new one, 207

Haidinger, Mr, on the parasitic forma^
tion of minerals, 86

Harvey, George, Esq., on a remarkable
formation of clouds, 33 — on a splendid
luminous arch, 146— on an interesting
meteorological phenomena, 148

Heineken, Dr, on the meteorology of
Funchal, 73

Kenwood, W. J., Esq., on steam engines
in Cornwall, 34 — his quarterly account
of the performance of steam engines in
do., 137, 213— on the temperature of
mines, 234

Hercuhmeum, on the buried city of, 188

Herschel, J. F. W., Esq., on the insen-
sibility of the eye to particular colours,

153 his experiments on refractive

powers, 296 — his experiment on the
cause of the dispersive power of oil of
Cassia, 308

Humboldt, M. A., his speech at the Con-
^ress of Philosophers at Berlin, 227

Infusoria, on the influence of light on
their motions, 346

India, on the geology of, 181, 371

Iron sinter, analysis of, 370

Juno, elements of its orbit. 176

Kater, Captain, on the luminous zone
of the 29ih September, 1/7

Kinfauns castle, meteorological register
kept at, 323

Kites for philosophical experiments, 7

Leelite, analysis of, 371

Light, on its influence on the motions of
infusoria, 346

Lovell, Joseph Dr, on the meteorological
register kept at the military posts of
the United States, 267

Magnetic needle, variations of in North
America, 22

Mantis, a tribe of leaf insects described,
351

Marmolite, analysis of, 371 ,

Marshall, Mr Samuel, his meteorologi-
cal observations at Kendal, 190 — his
summary for 1828, 222

Meteoric iron, on a mass of found in
France, 368

Meteorological phenomenon, on an in-
teresting one, 148

Meteorological register at Kotgurh, 139
Meteorological registers kept at the mi-
litary posts of the United States,^267
— at Kinfauns Castle, 323
Microscope, account of improvements
upon the, 327 — Dr Goring and Mr
Pritchard's work on it, 360
Minerals, on their parasitic formation,

86
Mines, on their temperature, 234
'Molecules of bodies, on their motions,

215
Mollusca, on a singular species of, from

Ceylon, 35 1
Naples, physical notices on the Bay of,

108, 245
Natural history, Mr Stark's Elements of,
analysed and recommended, 164—173
Nebulae and clusters of stars, 282
Niagara, account of the falls of, 316
Nontronite, a new mineral, 150
Obituary of fellows of the Royal Society

of London, 187
Odours, on the influence of electricity on,

368
Opals in a soft state, 31
Organic remains in Forfiirshire, 184
Paste, siliceous in marble, 24
Patents, Hst of Scottish ones, 187, 376
Pausilipo, on the district of, 245
Pearse, John, commander, R. K. on the

formation of anchors, 220
Pollen, on the granules of, 97
l^mpeii, on the buried city of, 113
Prinsep, James, Esq. on the permanent

increase of bulk of cast iron, 356
Pritchard, Mr A. his diamond and sap-
phire lenses, 327 — his work on the mi-
croscope analysed, 300
Quartz, recent formations from a soft

and fluid state, 28
Radiolite, analysis of, 370
Rfliatea, mean temperature of for 1822,

280
Rainbows, on two remarkable ones, 163
Kaspail, M. on the granules of pollen,
97, his observations on Mr Brown's
experiments, 106
Refractive powers of bodies, 297
Resistance of fluids, experiments on the,

355
Repetti, M. on quartz crystals in Carrara

marble, 24
Rice, W. Macpherson, Esq. on an an-
cient vessel found in the Rother, 56
Royal Society of Edinburgh, proceedings

of, 174, 362
Saline lake of Loonar, 1 86
Sapphire lens for microscopes, 327
Sensitive plant, properties of the, 186
Sharpening apparatus described, 359
Silver and its alloys, melting point of, 370

INDEX.

383

Simond, M. L. on ' the eruptions ot
Mount -^tna, 310 — Account of the
large chestnut tree of Mount ^tna,
314

Society of Arts, proceedings of, 3f>3

Societies, proceedings of, 174, 3fi2

Sound, velocity of, in the Arctic Regions,
368

Sounding board, account of a new one,
357

Spots on the sun, 13

Springs, on burning ones in America,
321

Stabiae, on the buried city of, 1 14

Stark, John, Esq. his Elements of Natu-
ral History analysed and recommend-
ed, 164—173

Stars, on Nebulae and clusters of, 282,
on double ones, 301

Stewart. Dugald, Esq. biographical sketch
of the late, 193

Storm in the desert, account of one, 319

Stylidium graminifolia, on the sensitive
properties of the, 185

Sympiesometer, on its defects for mea-
suring heights, 334

Temperature, mean of Bombay, 17

Temperature mean, of Falmouth, 178 —
of Military posts in theUnited States,
267— of mines, 234— of Raiatea, 280

Thermometer, on self- registering ones,

159
Threlkeld, Rev Mr, his meteorological

observations at Raiatea, 280
Thunder storms, account of two remark-
able ones in Worcestershire, 81
Tin mines of Cornwall, 180
Tourmaline, electrical properties of, 50
Tregaskis, Richard, Esq. on the law of

the expansion of vapour, 68^ 72
Turtle fossil, 185

Type-founding in Scotland, history of, 5
Ultramarine, on the process for making

it, 359
Vapour, on the law of its expansion, 68,

72
Vesuvius, on the height of, 135
Vessel, on an ancient one found in the

river R other, 56
Walker, James, Esq. on the resistance of

fluids, 355 — his comparison of water

and land carriage, 356
Weston, C. H. Esq. on the penetration

of water into bottles immersed in the

sea, 144
Wilson, Prof. Alex., life of, 1
Williams, John, Esq. on two remarkable

thunder storms, 81
WoUaston, Dr, his bequest to science,

186 — his differential barometer, 354

DESCRIPTION OF PLATES IN VOL. X.

PLATE I. Fig. 1, New Steam-Engine Valve, p. 42.

Fig. 2, Situation of the Ancient Vessel found under the old bed of
the River R other, p. 56.

Fig. 3, Stroke of Lightning on the Spire of St Andrew's church in
Worcester, p. 82.

Fig. 4, Interesting Formation of Clouds at the entrance of Ply-
mouth Sound, p. 148.

Fig. 5, Mr Forbes's Self- Registering Thermometer, p. 159.
PLATE II. Fig. 1, 2, 3, Represents a Niew Gravimeter invented by Don Busta-
mente of Mexico, p. 207-

Fig. 4, 5; 6, 7, Diagrams illustrative of Commander Pearse's paper
on Anchors, p. 220.

Fig. 8, Diagrams illustrative of Mr Kenwood's paper on the Tem-
perature of Mines, p. 239.

Fig. 9, 10, Represent the New Sounding Board invented by tlie
Rev. Mr Blackburn, p. 357.

Fig. 1 1, Represents Mr Gibson's Pneumatic Medical Spoon, p. 360.

EDINBURGH :
raiNTED BY JOHN STARK,

Old Assembly Close.

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