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phenomenon. M. Godehoue has published curious obfervations
on a kind of fish, called in French Bonite, and resembling the
tunny, in which there is an oil that fhines with a confiderable
luftre; and though he has obferved, and accurately described,
feveral of the luminous infects that are found in fea-water, he
is, nevertheless, of opinion, that the fcintillation and flaming
light of the fea proceed from the oily and greafy substances with
which it is impregnated.

The Abbé Nollet was long of opinion, that the light of the
fea proceeded from electricity; but he afterwards feemed in-
clined to think, that this phenomenon was caused by small ani
mals, either by their luminous afpect, or at least by fome liquor
or effluvia which they emitted; he did not, however, exclude
other causes among thefe, the spawn or fry of fish deserves to
be noticed. M. Dagelet, failing into the bay of Antongil, in
the island of Madagascar, obferved a prodigious quantity of
fry, which covered the furface of the fea above a mile in
length, and which he, at firft, took for banks of fand on ac-
count of their colour; they exhaled a disagrecable odour, and
the fea had appeared with uncommon fplendor fome days before.
The fame accurate obferver, perceiving the fea remarkably lu-
minous in the road of the Cape of Good Hope, during a perfect
calm, remarked that the oars of the canoes produced a whitish
and pearly kind of luftre: when he took in his hand the water
which contained phofphorus, he difcerned in it, for fome mi-
nutes, globules of light as large as the heads of pins. When
he preffed thefe globules, they appeared to his touch like a foft
and thin pulp; and fome days after the fea was covered, near
the coafts, with whole banks of thefe little fish, in innumerable
multitudes.

Thus it is probable, that various caufes contribute to the light and fcintillation of the fea; and that the light, which our Author attributes to agitation and friction, is different from that which is extended far and near, feems to cover the whole furface of the ocean, and produces a moft striking and fingular appearance in the torrid zone, and in the fummer season.

This hypothefis was alfo maintained in a treat fe published at Venice, in 1746, by an Officer in the Auftrian fervice, under the following title, Dell' Eletrecifmo.

ART. VI.

Defcriptions des Volcans eteints du Vivarais & du Velay-A Defcription
of the Volcanos of the Vivaraís and Velay, that are now extin
guished. By M. FAUJAS DE SAINT FOND. Folio. Paris. 1778.

HIS noble work, which is enriched with twenty-five plates,

T curioufly after drawings on un

der the inspection of the Author, will, no doubt, attract the at-
tention

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tention of the Public in a particular manner, as the discoveries of Sir William Hamilton, and other naturalifts before him, relative to volcanos, have produced a confiderable revolution in our ideas, with respect to one important branch of the theory of the earth. If any one had affirmed, twenty years ago, that all the extent of Italy, from Rome to Sicily, derived its fertility from the fubterraneous tillage of volcanos, that these fiery eruptions formed the mountains from whofe fummits they fend forth their Hames, that the greateft part of the cities of Auvergne, Velay, and Vivarais are built upon ancient volcanos, in a compass of more than 80 French leagues, and that the foil of thefe different provinces, where the eye beholds, at prefent, rich harvefts, enamelled meadows, and blooming orchards, is a compound of bodies vitrified, calcined or reduced to afhes, he must have expofed himself to contradiction, and perhaps to ridicule. And had any adventurous theorift gone a ftep farther, and maintained that the furprifing rocks, which rife in the midst of thofe diftricts (whofe bowels were formerly tormented with fubterraneous flames), and which in their colour and hardnefs refemble iron, were, themfelves, originally melted and formed, amidft fulphur and bitumen, in thofe immenfe furnaces, and thrown up from thence in tremendous explofions, -the man would perhaps have been looked upon as delirious.

Nevertheless, by fome late near and bold approaches to the fublime terrors of Etna and Vefuvius, and by a close examination of the various bodies, thrown up by their eruptions, it has been found, upon comparison, that bodies of a like nature have been obferved in many countries, where the existence of no ancient volcano had ever been fo much as imagined. The difcoveries of M. Guetard, who obferved the remains of volcanos at Volvic, Pui de Dome and Mont d'Or in Auvergne, and mentions other mountains in France, which formerly fent forth ftreams of lava, are well known. In the year 1760, M. Defmareft publifhed, in the Memoirs of the Academy of Sciences at Paris, his Obfervations on the Bafaltes of Germany, and, at the fame time, on thofe of Cauffe de Beffan and St. Tibery, in the lower Languedoc. We find alfo in the fecond volume of M. Guetard's Memoires fur differents Parties des Sciences et des Arts, a memoir concerning the Bafaltes of the ancients and moderns. M. Guetard, when he publifhed this memoir (in 1770) ascribed the formation of the prifinatic columns of the Bafaltes to the depofition of ftony matter from an aqueous fluid, but afterward renounced this opinion, when, vifiting, with the Author of the Work now

* See an account of thefe Obfervations in our jad Vol. p. 619.— See alfo Vol. 51ft, December, 1774. p. 458. for an account of the Bafaltic rocks of Staffa, defcribed by Mr. Pennant.

C

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before us, the extinct volcanos of Vivarais, he perceived that the Bafaltic columns had the fame origin with the lava.

Our ingenious Author gives here a compleat and circumstantial account of the extinct volcanos of Vivarais and Velay; and confines himself to thefe, as Meffrs. Guetard, Defmareft, and Montet have undertaken the defcription of the volcanos of Auvergne and the lower Languedoc. The frontispiece of this vo lume exhibits on a double folio-leaf, a view of the principal volcanos, already known, and which continue to emit flames, fuch as Etna, Vefuvius, Hekla, Mount Albours, near Taurus, the ifle of Fuego or St. Philip, the Pike of Teneriffe, the volcanos of Arequipa, Carrapa, Malahallo, &c. Thefe volcanos are reprefented in their natural fituation and forms, after the most accurate drawings and the beft relations, and to a circumftantial defcription of each, the Author has added a chronological table of their most remarkable eruptions. This is a kind of Introduction to our Author's main object, the extinct volcanos of Vivarais and Velay.

M. FAUJAS DE SAINT FOND begins by an enumeration of all the authors, whether ancient or modern, who have made mention of the Bafaltes in maffes or prifms, and he examines their different opinions relative to the nature and origin of that fubftance. He then proceeds to give a chemical analysis of the Bafaltes, and of the different heterogeneous bodies, which either naturally or accidentally are incruftated with it, fuch as the matrixes of granite, fpath, calx, quartz, filex, or flint, zeclite and fchorl or cheorl, whether they be in irregular mafles or in chryftals. The Reader will find here an accurate reprefentation of the Bafaltes in all its different forms, in maffes, in balls, in columns caft, as it were, in one mould, in jointed columns, Jiratum fuper ftratum, together with fpecifications of the differentkinds of lava, folid and porous, of the peperins, the Tufa, the pouzzolanes, and the methods of employing this latter fubitance in cement and buildings.

We meet next in this Work with an accurate map of the Vivarais and Velay, with drawings of the craters or mouths of the extinct volcanoes, and marks to indicate the places where the feveral volcanic bodies are difcernible. This is followed by the Author's journals of the different excurfions he has madem thefe provinces; and these journals are both entertaining and inftructive; they contain defcriptions and reafonings concerning volcanic eruptions, that illustrate several branches of natural hiftory, and may be made ufe of in bringing to farther degrees of perfection the theory of the earth. They are alío accompanied with drawings, which exhibit ftupendous views of Bafaltic columns, which our Author calls Giants Causeways, making a generical name of a denomination that has been hi

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therto

therto confined to the Bafaltic maffes and columns in the county of Antrim in the north of Ireland. It now appears that volca noes were the giants that formed thefe ranges of columns, whofe erection is unaccountable on any other principle, and which the facts alleged by our Author, by Sir William Hamilton, the learned Ferber, De Saufure, and other celebrated naturalifts, render abundantly evident.

It is proper to obferve, in concluding this Article, that all the plates, each of which is accompanied with an interefting explication, have been engraven after drawings, made from the objects, by M. A. Ed. Gautier Dagoty, whofe excellent talent for drawing and engraving has been happily animated, on this occafion, by his warm attachment to the ftudy, and zeal for the improvement, of natural hiftory.

ART. VII.

Nouveaux Memoires de l Academie Royale des Sciences et Belles-Lettres, annie 1775, Avec Pifcire. -New Memoirs of the Royal Aca. demy of Sciences and Belles-Lettres of Berlin, for the year 1775, with the History relative to that year. Berlin. 4to. 1778. HISTORY OF THE ACADEMY.

TH

HIS Volume exhibits too large a quantity of interesting materials to admit of our paying any attention to the ingenious adulation of the Perpetual Secretary on the anniversaries of the king's birth and acceffion; or to other transactions of the Academy that appear to us of inferior moment.

The first thing worthy of notice we meet with in the Hiftory of the year 1775, is the extract of a letter from M. D'ANSSE DE VILLOISON, member of the Academy of Infcriptions at Paris, and of thofe of Berlin, Gottingen, Manheim, &c. to M. FORMEY, in which he mentions his defign of giving a new edition and a Latin Tranflation of Cornutus his Treatife on the Nature of the Gods, which (in a very maimed and innacurate condition) is inferted in the Opufcula Mythologica of Gale; under the name of Phurnutus. As M. de Villoifon confiders this work as of the utmost importance to mythological fcience, and as containing a catechism and abridgment of the doctrine of the Stoics, he has taken confiderable pains on this edition. From fix MSS. in the French king's library, feven at Florence, and one at Augfburg, he has been enabled to correct above fix hundred paffages of this Author, and to restore a multitude of words, and alfo of whole lines, that are wanting in the prefent editions. He has also added a confiderable number of critical, grammatical, and philofophical notes, in which he either gives an account of the changes he has made, or illuftrates the doctrines of the Stoical philofophy, or explains the allufions to that philofophy, which Cornutus makes fometimes in a fingle word. But this is not

all;

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all; for M. D'ANSSE DE VILLOISON proposes, in this letter,
to prefix to his edition of Cornutus, a Treatise of his own com-
pofition (in Latin) concerning the natural Theology of the Stoics,
in which all the tenets of their theology, cofmology, cofmogony,
and phyfiology will be amply illuftrated. By the accounts,
which this young philologift gives of the multitude of authors,
both among the ancient philofophers and the most learned fa-
thers of the Chriftian church, that he has confulted in order to
render this treatise complete, we are led to expect in it a mafter-
piece of erudition and philosophical history.

We find by another fragment of a letter from this learned
Academician, that he defigns alfo to publish soon, an edition of
Longus, author of the delightful Greek romance, entitled, The
Loves of Daphnis and Chloe. Beside the corrections of the text
of this elegant writer, furnished by rare and valuable MSS. we
are made to expect a correction of the Latin Verfions of Moll
and Jungerman, and also an indication of the parallel and imi-
tated paffages in Homer, Euripides, Anacreon, Theocritus,
Mofchus, Bion, Mufæus, Thucydides, Xenophon, Plato, Lu-
cian, Philoftratus, Alciphron, Heliodorus, Achilles Tatius,
Charito, and Xenophon the younger.

Report of the Contents of a Memoir of Profeffor MAYER, con-
cerning the length of a fimple Pendulum at Grypfwalde.

A Memoir of the Abbé PERNETY, concerning the means of
making Boats fail against the currents of Rivers. After having
mentioned the various means that have hitherto been con-
trived by mechanifts to produce the effect indicated in the
title of this Memoir, the ingenious Abbé obferves, that none of
them seems to have thought of comparing the current of wa-
ter with the current of air, and of contriving a machine, on
which the force or power of the former might produce the effect,
which is produced by the latter on the fails of a fhip. It is by
combining (fays he) the ratio, or proportion that certainly
exifts between the currents of air and currents of a river that
the method of inventing and applying to a boat the machine in
This is all that we find
question may be more eafily hit upon.
in the Memoir of M. PERNETY, which is only the expreffion
of a wish, without any other directions or mechanical principles
for its accomplishment, than thofe which are laid down in M.
Bouguer's excellent Treatife De la Manoeuvre des Vaisseaux, to
which accordingly he refers the Reader.

Concerning magnetic Cures performed at Vienna,-This is the
declaration given by fome academicians to Baron Van Swieten,
the Imperial minifter at Berlin, who defired an explication of
their fentiments, relative to the great things Doctor Mefmer and
the Abbé Hell had performed at Vienna by the loadstone.
This declaration regards more particularly a letter addreffed, by

the

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