made a great number of experiments, in different feasons, in order to find out the true cause of this phenomenon; and he always found, that these luminous points were produced by friction alone. Though he often made use of the best glaffes, he could never perceive any infect; and therefore he is inclined to think, that these luminous points are rather the effects of motion and friction, than of animal bodies, as has been supposed by fome philofophers. He does not, indeed, maintain his hypothefis with a decifive tone, nor pretend to give it an exclufive authority; and here his modefty is becoming, and will perhaps prepare him for a change of opinion, when he has given due attention to the experiments and obfervations of other learned men upon this fubject. And, indeed, this phenomenon has been treated by philofophers fo far backward as Bacon and Boyle, and fince by Ozanam, Bartholin †, Donatit, Nollet §, Vianelli, and other writers. From thefe and other refpectable authorities, which we shall here bring together, in order to the decifion of this curious queftion, it appears evident, that various caufes, both jointly and separately, produce this phenomenon. In the Philofophical Tranfactions for the year 1769, Mr. Canton's experiments prove, that the putrefaction of animal fubftances produces light and fcintillation in the fea. A little white fish placed in fea-water rendered it luminous in the fpace of twentyeight hours; and certain quantities of falt, and oil of hartfhorn, are known to produce a fimilar effect in common water. On the other hand, it is certain, that there is in the fea a prodigious quantity of fhining infects or animalcules, that contribute to the phenomenon now under confideration. M. Dagelet, a French aftronomer, who returned from the Terra Australis in the year 1774, brought with him several kinds of worms, which fhine in water, when it is fet in motion; and M. Rigaud, in a paper inferted (if we are not miftaken) in the Journal des Savans for the month of March 1770, affirms, that the luminous furface of the fea, from the port of Breft to the Antilles, contains an immenfe quantity of little, round, fhining polypufes of about a quarter of a line in diameter. Other learned men, who acknowledge the existence of thefe luminous animals, cannot, however, be perfuaded to confider them as the caufe of all that light and fcintillation, that appear on the furface of the ocean: they think that fome fubftance of the phofphorus kind, arifing from putrefaction, must be admitted as one of the causes of this In his Treatife concerning Phosphori. + In his Differt. de Luce Animalium. 1 In his Hiftory of the Adriatic Sea. Memoirs of the Royal Academy of Sciences, for 1750. In a work entitled, Nuove Scoperte intorno le Luci nottorno dell' Aqua Marina. pheno 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 shines 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 inclined to think, that this phenomenon was caused by small ani mals, either by their luminous afpect, or at leaft by fome liquor or effluvia which they emitted; he did not, however, exclude other causes among thefe, the fpawn 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 first, took for banks of fand on account of their colour; they exhaled a difagreeable odour, and the fea had appeared with uncommon fplendor fome days before. The fame accurate obferver, perceiving the sea remarkably luminous 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 phosphorus, he difcerned in it, for some minutes, 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 feafon. 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 Vivarais 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, curioufly engraved after drawings made on the fpot, under the infpection of the Author, will, no doubt, attract the atL13 tention 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 refpect 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 Aames, that the greatest 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 midft 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, amidst 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) afcribed 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 j2d Vol. p. 619.See alfo Vol. 51ft, December, 1774. p. 458. for an account of the Bafaltic rocks of Staffa, defcribed by Mr. Pennant. before 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 circumftantial 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 Jume exhibits on a double folio-leaf, a view of the principal volcanos, already known, and which continue to emit flanies, 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, Malahalls, &c. Thefe volcanos are reprefented in their natural fituation and forms, after the most accurate drawings and the best 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 fiint, zeelite 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, firatum fuper ftratum, together with fpecifications of the different kinds 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 inftruct.ve; they contain defcriptions and reafonings concerning volcanic eruptions, that illuftrate feveral 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 Caujeways, making a generical name of a denomination that has been hi L14 therto therto confined to the Bafaltic maffes and columns in the county of Antrim in the north of Ireland. It now appears that volcanoes were the giants that formed these ranges of columns, whose 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 interesting 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 l'Hificire.—New Memoirs of the Royal Academy of Sciences and Belles-Lettres of Berlin, for the year 1775, with the Hiftory relative to that year. Berlin. 4to. 1778. TH HISTORY OF THE ACADEMY. 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 accession; 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 Hiftery 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 Translation 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 science, 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 alfo 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 |