Chap. 34-1 [ 215 ] 



CHAP. XXXIV. 



SILVER. 



Character of the perfetf Metals,* General Properties cf Silver. J r egt<- 

 tat ion of Silver* Natural Hijlory cf Silver. AJfayirig of Si/-z'er. 

 Cupellation. Lunar Caujiic.-~-Fulmina.ting Silver. Luna Cornea. 

 ^-Diana's Tree. Green Gold. Standard Silver Coin* Plating 

 fwitb Sil<ver' t hmu performed. Frenib Plate, 



OF the different metallic fubftances only three 

 have been dignified by chemifts and mineralo- 

 gifts with the appellation of perfect, viz. filver, gold, 

 and platina. Thefe are diftinguifhed from the other 

 metals by their weak attraction for oxygen, which 

 enables them to retain their purity and metallic Iplen- 

 dor in fituations in which other metals become gra- 

 dually covered with ruft or calx. Silver is the whiteft 

 of all metals, and is pofleffed of great brilliancy ; it is 

 harder than gold ; in weight it is exceeded by gold, 

 platina, quickfilver, and lead ; its gravity being only 

 about ten times that of water. Its malleability is 

 fo great, that a grain of it reduced to ordinary filver 

 leaf meafures about fifty- one fquare inches, in which 

 ftate it is not more than the hundred and fixty thou- 

 fandth part of an inch thick, which, however, is confi- 

 derably more than one third thicker than gold leaf. 

 Its tenacity is fo confiderable, that it may be drawn 

 into wire about half the thicknels of a fine human 

 hair, and a wire of one tenth of an inch in diameter 

 will fupport the weight of two hundred and feventy 

 pounds without breaking. It is very fonorous, but in 

 hardnefs and elafticity it is not equal to copper. It 

 P 4 hardens 



