[ 39> ] 



of chemical attraftion has impofcd on fome perfons 

 fo far as to be confidcred as an adlual tranfmutation '>f 

 iron into copper, but is in fad a mere precipitation. 



In Combination with other Metals. 



Copper readily unites with other mctallick fub- 

 ftances, and affords various compound metals. 



Thus copper with about i-4th part of zinc forms brafs. 



with i-iothoftin — bell-metal 



— — with i-8thofarfenick — white copper. 



It is moreover the bafis of bronze, fpecula, Bath- 

 metal, Prince's -metal, and all the yellow compounds 

 prepared in imitation of gold. Even filver receives 

 an alloy from copper, before it can acquire a proper 

 degree of hardnefs for plate. 



Brafs is lefs difpofed to contract ruft than copper, 

 and bell-metal than brafs; white copper lead of all; 

 but the arfenick in its compofition alone renders it 

 totally unfit for culinary ufe. If acid liquors are fuf- 

 fered to (land a few hours in any veflel containing 

 a mixture of copper, they acquire a bad tafte, and 

 confequently a flight impregnation of the metal. 

 Nor are filver veflels wholly exempt from this in- 

 convenience, efpecially fuch as arc confiderably 

 alloyed with topper. 



Effe^s 



