ON SltVER. S6d 



octahedra. 1 have a piece of four ounces, in which % 

 horizontal matrix is formed, that is lined with these crys- 

 tals. The solution of the muriat in ammonia likewise 

 deposits regular octahedra. 



The ammoniacal solution will keep several years, with- Ammoniacal 

 out the muriat's tending to decomposition: but if a sepa- k^^prion? *^ 

 ration be forced to take place, even by a moderate heat, but being de- 

 fulminating oxide may be formed. This I learned from composed by 4 



T . 1 . . gentle heat, 



the following fact : — I placed a capsule containing some fulminating 



of the ammoniacal solution in a moderate heat, for the silver fofmed. 

 purpose of collecting the muriat. The liquor being eva- 

 porated to a certain point, and a few grains of precipitate 

 having formed, I took it up by the edge, and with blame- 

 able carelessness put it into my other hand. The pow- 

 der at the bottom immediately exploded, cracked the 

 bottom of the capsule, and blew all the liquor into my 

 face. Happily I escaped with no other mischief than the 

 fkin's remaining black for some days. 



To form a clear idea of the characters of this muriat, Method of ex-- 

 and even to make it known in teaching others, it should l^i^iting it to 

 be poured when half red hot into a silver basin, and 

 moved about circularly, as you would melted nitre. 

 You may then turn it out in a thin, transparent, flexible 

 plate, which may be cut with scissars almost like the 

 horn for lanterns. 



If you let it cool ia the crucible, to have it in thicker Large pieces 

 pieces, they may be turned, and made into snuff-boxes, P*y ^*^ turned 

 as Kunckel observed ; which succeeds better with large *° ° ^^^' 

 pieces than small. I have plates of it of a reddish tint, Ganges their 

 and marbled like tortoiseshell ; I?ut exposure to the light colour, 

 makes it more and more brown, which lessens the value 

 it would otherwise have in jewellery. 



Kunckel, in his Chemical Laboratory, gives a method Kunckel's mc- 

 of reducing the muriat, which is expeditious, and not tl^od of reduc- 

 liableto much loss. Put three parts of lead, he says, '"^ ^'' 

 with one of hma cornea, into a retort, and expose them 

 to h^at; the lead will be converted into muriat, and the 

 reduced silver will subside to the bottom. The product, 

 however, will not be reduced silver, for it will require 

 cupellation, to separate from it a considerable portion of 

 Jead^ This process is susceptible of improvement. Three 



parts 



