2C)Q EXPERIMENTS ON VARIOUS ALLOYS OF GOLB, 



GOLD ALLOYED WITH TIN. 



Experiment I. to IV. 

 Gold and tin. A confiderable portion, as -^ of tin rendered gold paler and 

 lefs ductile : frnall quantities as 7 ^ did not material injure it. 

 Mr. Bingley, in confequence of Tillet's experiments, related 

 in the Acad. Par. 1790, and in the Quarto Series of our 

 Journal II. 140, 179, made experiments on an alloy of gold 

 and tin, containing eight grains in the ounce of the latter 

 metal. The fa&s are, 1. the earlier chemifts, probably as 

 Mr. Hatchett obferves, milled by a tin containing bifmuth, 

 lead, antimony or zinc, did affirm that the fmalleft portion 

 of that metal renders gold brittle ; 2. Mr. Alchorne mewed 

 the fallacy of that general pofition, by experiments on fuch 

 alloys. 3. Mr. Tillet (hewed that tho* gold alloyed with tin, 

 may be hammered and laminated cold, yet it falls to pieces 

 by the annealing heat, or cherry red ; and laftly, Mr. Bingley 

 iinds that an annealing by five degrees of Wedgwood's pyrome- 

 ter, or red vifible by day light, does not render the gold unfit 

 for working ; but that the cherry red or 1 ten degrees blifters 

 the furface, warps the bar, and caufes it to fall in pieces, by 

 the fufion of the molt fufible metal ; a general property on 

 which the procefs of eliquation depends. 



GOLD ALLOYED WITH IRON. 



Experiment* I. to IV. 

 Gold a»d iron. Gold, with and without copper, was alloyed with about ■—• 

 part of iron, and in other experiments of call iron, caft fteel, and 

 iron wire, gave a metal of a pale yellowifh gray, approach- 

 ing to a dull white, which was very ductile and laminable, 

 and was damped with great eafe without annealing ; though 

 it was harder than gold. 



EXPERIMENTS ON EMERY AND GOLD. 



Emery a»d Gold was heated ftrongly, and for a long time, with emery 



g°id; in fine powder, and in fome trials previoully heated with oil. 



No change was produced. 



GOLD ALLOYED WITH PLATINA. 



Gold and pla- Fine gold, and alfo ftandard gold, were alloyed with pla- 



ti* 1 ** tina. The compound was yellow jili-while, and very ductile. 



3 It 



