A 



JOURNAL 



OF , 



NATURAL PHILOSOPHY, CHEMISTRY, 



AND 



THE ARTS. 



NOVEMBER, 1803. 



ARTICLE L 



Experiments and Ohj'ervatians on the various Alloys, on the Specific 

 Gravity, and on the comparutive Wear of Gold. AbJiraSied 

 from the Memoir of Charles Hatchett, Efq. F. K. S. 

 in the Philof. Tranf.for 1S03. 



( Concluded from Vol. V. Page 303 of our Journal.) 

 Experiment I. 



i. WELVE pieces of ftandard gold were firfl: examined, and Lofs of ftandari 

 were placed fo that fix were oppofed to fix. ^"^'^ ^^ ^"^'°"* 



The brafs frame, in which each upper piece was, fixed, 

 weighed IbOl grains; and it was found neceflary to add to 

 each a weight of lead, equal to 19825 grains; fo that the 

 pieces were rubbed againft each other under the preflure of 

 19825-{-1604-=:2I429grains = 3lb. Soz. ]2dts. 21grs*. 



* This weight was not employed till repeated trials had proved 

 the extreme difficulty, and almoft impoffibility, of producing any 

 perceptible effedl: with lefs, in a moderate period of time; and, 

 even with this weight, the expex'iments were found to be exceed- 

 ingly tedious. The only evil which refulted from fuch a preffure 

 was, that the comparative wear of the fine gold appeared much 

 more confiderable than would have been the cafe, if a fmall weight 

 could have been employed ; fome obfervations will therefore be 

 found in the lubfequent pages, which point out the neceflity of 

 making an allowance for this circumftance. 

 « Vol. VL— November, 1803, L The 



