Defcrlpiion of an Ajfay -furnace. 25^ 



greater part of metals, but not with lead, iron, or bifmuth ; 

 and it may be amalgamated with quickfilver. This amal- 

 gam of zinc is very proper for ftrengthening the power of an 

 electric machine, and Higgins has given a prefcription for 

 preparing it. In the dry way it has the greateft affinity with 

 copper, and produces with it a more or lefs yellow compofi- 

 tion, which can be obtained by no other metal. In this re-» 

 fpeft, then, it is effentially different from all other metals, 

 and becomes itfelf a very ufeful one, as it is ufed for brafs, 

 pinchbeck, prince's metal, bronze, Manheim gold, and in 

 fire-works, Sic. 



It is very remarkable, in regard to zinc, that neither ful- 

 phur nor liver of fulphur ' produces on it anyeffeft; whereas 



L, gold, which fulphur cannot overcome, is diffolved by liver 



V of fulphur. 



y On this occafion I cannot omit making mention of tlie 

 celebrated alkaheft of Kcfpur, who believed, that when he 

 alcalifcd zinc and rendered it cauflic, and had obtained from 

 it a purple-coloured mafs, volatile in the open air, he had 

 found out a menftruum, by which he could radically dii- 

 folve all metals. A paradoxical pofition, which was long 

 adopted by the gold-making alchcniifts, but which has never 

 been realifed. 



[To be concluded in next Number.] 



VI. Defcript'ion of mi Af]'ay furnace^ ivith an Apparatus 

 for vicafuring the Degree of Heat employed. By Mr. 

 David Mu SHE T of the Clyde Iro7i IVorks. Communl- 

 sated hy the Author. 



\ X my lafl: paper I mentioned, that, in order to facilitate 

 the operations of the allay-furnacc, and to compare the va- 

 rious degrees of heat in which different experiments are 



• It Ivjs hecn afccrtuincd that zinc and fuljihur can be united; but ilie 

 proccfs is diflicult, on account of the calV oxidation and volatiJity of ih; 

 zinc. Sec Men. ilc l)iio!:, i;?^. 



cffcacd. 



