41 5 ffidgrapbita! Memoirs of P. Bay en. 



that there cxius forne alfo, which is united to a very fmall 



quantity of the arfenical fubftance. 



His analyfes taught him alio, that the tin ufed in com- 

 tnerce, and that manufactured by pewterers, contain copper 

 and antimony, which render it hard ; zinc, which gives it 

 & white colour; bifmuth, which renders it fonorous ; and, 

 above all, lead, which diminithes its value. It is in particular 

 this metal fraudulently united with tin, that can render the 

 latter dangerous *, as both thefe fubftances are foluble in 

 vegetable acids. Scarcely had Bayen's refearches on tin been 

 Biade public, when the uneafmefs excited by Margraff and 

 Henkel vanifhed. It was clearly proved, that the very fmall 

 quantity of arfenic contained in tin cannot abfoiutely be 

 hurtful, and no more ideas were entertained of banifhing a 

 fpecies of veffels fo long employed by our anceilors. 



Haven had fuch a habit of considering objects, and of 

 judging of their composition by the analyfes he had made of 

 analogous objects, that it was often iufneient for him to fee 

 ana to touch them in c wter to tell their nature. As a proof 

 of this anertion, may be mentioned the opinion which he 

 gave of one of the marble baluftrades in the Fhue de la Revo- 

 lutfan. Notwithstanding the polifli and apparent iblidity of 

 this marble, he foretold that it would decay iu a very little 

 time; and he pointed out to Deyeux, who was prefent, the 

 different places where the alteration would firft manifeft it- 

 felf, and thofe which would endure the longeft. Scarcely 

 had a year elapfed when the prediction began to be accom- 

 plifh^l ; and in lefs than three years the alteration was fo 

 great, that considerable excavations were formed in the 

 places pointed out. Bayen was of opinion, that the monu- 



* The pewter pets in common ufe in London conrsin IcjJ in their 

 eimpofhion ; and as all the beer drawn in them is more r lefs ac id 

 (ftali ), t is evident that thofe who ufe them are conflantly taking, though 

 in fiftall quantities, a folutir n of had, which is highly noxious. It is 

 very improper, there 'ore, to ufe beer which has ftoud in them for any 

 l&rgth oftime, Euit. 



nients 



