238 On the Caioptrical and Dioptrical 



6b. " It was reserved for the genius and ability of ST. dc 

 Buffon, to execute these machines with such happy success, 

 that he ought to be regarded as the inventor of them ; espe- 

 cially since we know, that, before the execution of these 

 plane mirrors, he had not read father Kirchcr*; that he 

 used methods of his own; that he has given them some 

 advantages ; and has brought them to such a high point of 

 perfection as was formerly unknown, and has left us no- 

 thing to wish for on the subject. 



69. " What wc have said only regards the recent history of 

 this invention. If we now examine its antient vestiges, we 

 shall find, that although it had been neglected for above 

 1000 years, when Kirchc.r revived it in the last century, it 

 is not on this account the less antient. 



70. "Antliem'uts, who lived under the emperor Justinian, 

 m the sixth century, not only contrived a way of making; 

 burning mirrors with plane ones, but found that twenty-four 



* From something in the manner in which Bujfon mentions Kircber, 

 I took it for granted (Lett. I. § 1.) I thought naturally enough, that he 

 had seen that father's book before he entered on his experiments. But, 

 as my ingenious author thinks differently, I beg leave to lay before the 

 reader a translation of Buffon s own words; of the fidelity of which he 

 may satisfy himself by comparing it with the original (for which I have 

 not room) in the Mem. del 'Acad, des Se. 1747- pp. 144, &c. Amst. edir. 

 *' While I was employed," says that celebrated philosopher, " on these 

 mirrors, I was ignorant of the detail of what the antients had said of 

 them; but I was not displeased to gain information in this respect, after 

 I had succeeded in making them. M. Melot of the Acad, of . Belt* s 

 Letlres, and one of the king's librarians, whose great erudition and ta- 

 lents are known to all the learned, had the goodness to communicate to 

 me an excellent dissertation, which he composed on this subject, and in 

 which he gives the testimonies of all the authors who have spoken of the 

 burning mirrors of Archimedes.'' — " In the same dissertation of M. Melot, 

 I found that Kircber had written, that Anbr^edes had been able to burn, 

 at a great distance, with piane minors." — " In fine, in the Mem- de. 

 L' Acad. 1726, M. du Fay t whose memory and talents I shall always 

 honour, appears to have touched on this discovery. At the end of his 

 Memoir, he says, that some authors (he means no doubt father Kircber) 

 have proposed to form a mirror of a very great focal distance, witli a 

 great number of small plain mirrors, &c." — Now I must fairly confess, 

 that it would not be easy to convince mc, "hat Bvffon, a celebrated philo- 

 sopher, in habits of intimacy with very many other celebrated philo- 

 sophers, was unacquaiuted not only with the works of Kircber, which, 

 as my author observes above, " are well known torhe learned," but with 

 a transaction better known to common fame than any other work of the 

 renowned Archimedes; a transaction, I had almost said, which every 

 school-boy has heard of. Was it not sufficientlv creditable to Buffon to 

 have verified that famous experiment, after it had been pronounced incre- 

 dible, and even impossible, by some of the greatest judges in Europe; 

 without aspiring at an entire originality of idea, by putting the credulity 

 of bis readers to so severe a trial ? — "translator. 



Of 



