fome hesitation on account of his distance from Edinburgh, Dr. Gleig acquiefced."

The unavoidable difficulties which this new edition had to encounter, for want of a proper clue to what had been already done, are afterwards mentioned. Dr. Gleig is now publishing a Supplement, in which the difcoveries, fubfequent to the printing of the former work, are to be explained, and other defi ciences fupplied.

When we take an exa& account of the diftinct treatises con→ tained in these volumes (not reckoning the hiftorical articles, which partake of the nature of treatifes) they do not turn out to be very numerous. It may be of fome advantage to the poffeffors or confultors of the work to have them here stated.

Befides thefe, which are printed in a diftinct form as treatifes, there are feveral long articles which well deferve that name,

fuch

fach as thofe of Refiftance, Scripture, Steam- Engine, Strength of Materials, and Water-Works, which is placed under WORKS, being omitted at the place of Hydraulics, where it should have stood.

On a general confideration of this extenfive work, we are well prepared to confirm the public opinion, that it offers many advantages, and well merits patronage. Of its defects we cannot fpeak more to the purpofe than the editors themfelves have done, in the foliowing words:

"After the utmost exertions, however, of our attention and induftry, we are fenfible, perhaps more fenfible than any of our readers, that the work paffes from our hands in a ftate far from perfection; and that the man who fhall not discover in the Encyclopædia Britannica miftakes, needlefs repetitions, and even culpable omiffions, will bring to the examination of it no great ftock of general knowledge. But for thefe offences, the editors perhaps need no other apology than what will be furnished by the nature of the work, and the hiftory of its publication."

This apology is undoubtedly, in moft inftances, fufficient; and it was certainly a very laudable effort of diligence and attention, to offer to the public a work of this kind, fo well executed altogether as the Encyclopædia Britannica,

ART. XIII. The Obfervations of Newton concerning the InFections of Light; accompanied by other Obfervations differing from his; and appearing to lead to a Change of his Theory of Light and Colours. 8vo. 134 pp. 4s. Cadell and Davies. 1799.

SIR

IR Ifaac Newton, in the third book of his admirable work upon Optics, arranges his experiments, relative to the inflections of the rays of light, under eleven principal obfervations. The anonymous author of the work at prefent before us, tranfcribes thofe obfervations of Newton, and after each of them fubjoins his own experiments and remarks; fome of which tend to correct, others to enlarge, and others again to confirm Sir Ifaac's original obfervations.

The experiments were performed in a dark room, into which a beam of the fun's light was admitted through a small hole. In the way of this beam of light various fubftances were fucceffively placed, and their actions on the light was manifested by the fhadows, or coloured fringes, &c. which they caft upon fcreens placed at different diftances.

Оо

BRIT. CRIT. VOL. XIV, NOV. 1799,

Such

Such was the principal or more general way of performing the experiments; but for further particulars, we must refer our readers to the work itself, where they will find the refult of the experiments particularly defcribed, and the defcriptions illuf, trated by diagrams, on nine fmall plates.

If the reader fhould with to know a fummary of this author's remarks, or the general tendency of his experiments, we fhall answer in his own words.

I have," fays he, "corrected all the Newtonian obfervations concerning the inflections of light.

"I have made obfervations concerning the inflections of light, which hitherto had escaped the attention of all who have confidered thefe phenomena.

"I have explained the manner in which the rays of light are bent and diftributed to produce thefe appearances.

"I have fhewn that the doctrine of modification and feparation in all cafes fufficient, is equally applicable with that of fimple feparation of the rays of light, to the phenomena of colours in the fingle cafe of arrangement of the fuppofedly diftinct rays, which alone can confift with the appearances.

"And thus I have prepared the way for a more eafy and natural folution of the phenomena of light, than by the hypothefes of fits and Species of the rays. These hypothefes, if I err not, are inconfiftent with the actual condition of things, and the general phenomena of light and of nature. They have not been, for they cannot be, applied to explain them; they obftruct all difcovery concerning them; they interrupt the general progreís of philofophy."

A little further on, and after having mentioned his intention of correcting the other two books of Newton's Optics, which he thinks ftand more in need of amendments, this author fays,

"The reformation of thefe parts of the Newtonian philosophy, which for more than a century have stood unqueftioned, and, been fo long confidered as eftablished beyond all reach or power of queftion, is of infinite importance and incalculable value to general philofophy. The phenomena of light, connected obviously with thofe of heat and electricity, which have to much engaged the attention and investigation of the prefent day, are really connected with all the phenomena of the univerfe. Without this reformation, it is abfolutely impoffible for philofophy to make further progrefs."

This author evidently lays too much ftrefs on the importance of his own experiments; and he speaks under a mistake, when he fays that Newton's optical affertions had hitherto been confidered as established beyond all reach or power of queftion; for notwithstanding the acknowledged excellency of his book on Optics, feveral objections have at different times been made, and fome corrections have been offered to it; which objections,

3

&c.

&c. may be feen in the recent works on optics, and in the tranfactions of feveral learned focieties.

Upon the whole, we think ourselves authorized to conclude by afferting, that though this author may view his labours in 100 partial a light, and notwithstanding his peculiar, or confequential ftyle, his work is certainly entitled to the attention of the philofophical world.

ART. XIV. Secret Anecdotes of the Revolution of the 18th Fructidor (September 4th, 1797) and new Memoirs of the Perfons deported to Guiana, written by themselves; containing Letters from General Murinais, Meffrs Barthélemy, Tronçon-du-Coudray, Laffond-Ladébat, De la Rue, &c. &c.—A Narrative of Events that took Place at Guiana fubfequent to the Escape of Pichegru, Ramel, Sc.-A Picture of the Prifons of Rochefort, by Richer-Serify-An authentic Account of the Captivity and Efcape of Sir Sydney Smith-A Memoire, by Barbé Marbois, &c. &c. forming a Sequel to the Narrative of General Ramel." Tranflated from the French. 8vo. Wright. 1799.

3s. 6d.

REVOLUTION fucceeds Revolution fo rapidly in France,

that we have scarcely time to deliberate on the atrocities of one defcription of confpirators, before the attention is again excited, and curiofity interefted, by new changes, new crimes, and new victims. In a former number, we defcribed the almost miraculous escape of Pichegru, Willot, Barthelemy, Ramel, &c. from the deftructive climate of Cayenne, as reprefented in a publication, to which this is a fequel. The papers here printed are affuredly authentic; but our principal inducement for giving it a place among our firft articles is, that it records the delivery of our gallant countryman, Sir Sydney Smith, from the rigours of his long and fevere imprisonment. Before, however, we enter into this detail, we paufe by the way, to infert two paffages, which prove that the capacity of contrition and remorfe cannot be wholly extirpated even from the bofoms of Jacobins. The reader of English history will alfo recognize fomething of the affected facetioufness of Cromwell and his crew, in the following narrative:

"When they came to that of Mare-Curtin, which the fecretary mifpronounced, "Who is that?" faid they; we know him not, he has never spoken,"-" Phaw!" cried a member of the deputation,

"no matter; he belonged to the League of Clichy, he must go with the reft;"and then they laughed.

The fame fteps were purfued with regard to the journalists. Bailleul, knowing the deftined victims better than the reft of his colleagues, was appointed to select them.

When the decree of deportation was brought to the Temple, Angureau, who was there, faid with fury," This is their conftant method; they fpoil every thing with their moderantifm;" and Bourdon de l'Oife, covering his face with both his hands, exclaimed in a melancholy tone, "Where shall I find a place to lay my head ?—I that have voted for the death of my king?"" P. 24.

The following cannot be read without emotion."

"Two hours after their arrival in the Temple, the deported per fons vifited the apartments in the tower. "This," faid La Vilheurnois, who acted as their guide," was the chamber of the unfortunate Louis XVI;" and Rovere raifed his hands towards heaven, ftruck his forehead, and retired with horror.

"The deported examined with the greatest attention the following fentences, written with a pencil on the wall of one of the apartments: "O my God, forgive thofe who have put my relations to death! O my father look down upon me from the heavens above! May the French nation be happy!"-" Gentlemen," faid La Vilheurnois, by thefe few words which the has infcribed, you may judge of the greatnefs of foul of the daughter of Louis XVI."" She was an angel," added the keeper: "as long as I am here, these lines shall never be effaced."-" You are a worthy fellow," faid Pichegru; and De la Rue wrote under the words, "May the French nation be happy!" the following fentence: "God will hear the prayers of innocence." P. 26.

We have made enquiry into the authenticity of the facts which the fubjoined extract relates, of Sir Sydney Smith's elcape, and have affurance that they may be entirely relied upon.

"Account of Sir Sydney Smith's Imprisonment and Escape.

"When I was taken at fea," faid the gallant Commodore, “I was accompanied by my fecretary and Mr. de Tr***, a French gentleman, who had emigrated from his country, and who, it had been agreed, was to pafs for my fervant, in the hope of faving his life by that difguife. Nor were our expectations fruftrated; for John (as I called him) was lucky enough to efcape all fufpicion.

"On my arrival in France, I was treated at first with unexampled rigour, and was told that I ought to be tried under a military commiffion, and fhot as a fpy. The government, however, gave orders for my removal to Paris, where I was fent to the Abbaye, and, together with my two companions in misfortune, was kept a clofe prifoner.

Meanwhile, the means of efcape were the conftant object on which we employed our minds. The window of our prifon was toward the treet; and from this circumstance we derived a hope fooner