COLLKCTtON OF MEMOIRS, 



81 



they are informed that the greateft part of the proof fheets work In the lad 

 were revifed in the laft days of the author's life; and thatjjj^^ 

 whilft he knew that his alfaffins were premeditating his death, 

 M. Lavofier, calm and intrepid, employed his laft moments in 

 a work which he confidered as ufeful to fcience, and gave a 

 great example of that ferenity which a virtuous and enlighten- 

 ed man can preferve in the midft of the moft fevere calamities. 



Part II.— Sect. I. Fifth Memoir, (Tom. II. p. 78.) 



Hifiorical Details concerning the Augmentation of Weight which 



the Metals ucijvire iihen heated tailh Contad of Air. (By 



Lavoifier.) 



IT is not my obiefl in this paper lo give a compleat hiftory Limit of this 

 r .t- j-rr ^ . , , , r ;y- i I , j hiftorical me- 



ot the dillerent opinions that have been luccetnvely adopted ^^jj.^ 



by the chemifts and natural philufophers on the caufe of the 



augmentation of weight in metals expofed to the a£lion of 



heat; fuch a hiftory would only ferve to fliew how much the 



rainds of men are fufceptible of being led aftray when they 



give themfelves up to the fpirit of theory, and how eafily we 



are deceived by reafoning, if it is not perpetually redlified by 



experiment, John Rey, a phyfician (medecin) little known John Rey an 



is one of the firft authors who has written on this fubje6l ; he "mbuJJon *""* 



lived in the beginning of the 17th century at Bugue in Peri- 



gord, and kept a correfpondence with the fmall number of 



perfons who cultivated the fciences at that time. 



Neither Defcartes nor Pafcal had yet appeared ; the va. His phiiofuphy 



cuum of Boyle, and that of Toricelli, the caufe of the afcent f" ejccecded that 



,.,..,., ..... , . , of his coterapo- 



ot hquids in tubes void or air, were unknown ; experimental raries. » 



philofophy did not exift; a profound darknefs reigned in che- 



miftry. Neverthelefs, J. Rey, in a work publithed in 1630, 



ifrith a view of determining the Caufe of the augmentation of 



weight which lakes place in lead and tin during their oxidation, 



difplayed views fo profound, fo analogous to the iafls which 



have been'fince confirmed by experiment, fo conformable to 



the do6lrines of faturation and affinity, that for along lime J 



could' not help fufpefting that tb.e eflays of J. Rey had been 



compofed at a much later period than that announced on the 



title page of the book. 



J. Rey, after having refuted fuccefsfally, not by fa6?s (for He contends that 

 at that time the art of making experiments was in its infancy) "^!^^'^ 8^'" 

 but by conclufive reafoning, (he different caufes to which thejirin oxidation. 



Vot. XIII.~-JANUARy, I80e, G aug^ 



