664 SILVER. 



portion of the powder is dissolved ; the solution, as it cools and 

 loses ammonia, yields small crystalline plates of a pale yellow 

 colour. The constituents of this salt are NO 5 , 2HgO and NH 3 . 

 Dr. Kane doubles its equivalent and represents it as a compound 

 of Soubeiran's salt with nitrate of ammonia, as it appears to be 

 produced by the solution of the former salt in the latter, (HgO, 

 NO 5 + Hg,NH 2 + 2HO) +NH 4 O, NO 5 . Soubeiran's ammo- 

 nia subnitrate is dissolved in considerable quantity, when 

 boiled in a strong solution of nitrate of ammonia and the solu- 

 tion deposits, on cooling, small but very brilliant needles, which 

 were observed and analyzed by Dr. Kane. Kane's ammonia sub- 

 nitrate is decomposed by water, nitrate of ammonia dissolving 

 and Soubeiran's sub-salt being left undissolved. It contains 

 the elements of 3(NH 4 O, NO 5 ) and 4HgO. Dr. Kane believes 

 that it is most likely to contain Soubeiran's subnitrate ready 

 formed, which leaves 2 atoms of nitrate of ammonia and 2 atoms 

 of water to be otherwise disposed of.* 



Nitrate of mercury forms an insoluble compound with sul- 

 phuret of mercury, HgO, NO 5 -f2HgS, resembling the com- 

 pounds of the sulphate and chloride with sulphuret of mercury. 

 It also forms double salts with iodide and cyanide of mercury. 



SECTION II. 



SILVER. 

 Eq. 1351.6 or 108.3; Ag (argentum). 



This metal is found in various parts of the world, and oc- 

 curring often in the metallic state and being easily melted must 

 have attracted the attention of mankind at an early period. 

 Before the discovery of America, the silver mines of Saxony 

 were of considerable importance, but the silver mines of Mexico 

 and Peru far exceed in value the whole of the European and 

 Asiatic mines ; the former have furnished during the last three 

 centuries, according to Humboldt, 316 millions of pounds troy 

 of pure silver. 



A considerable quantity of silver is obtained from ores of lead 

 by cupellation, as has already been described under that metal. 

 The native silver, which is in the condition of threads or thin 



* Trans, of the Royal Irish Academy, vol. xix. pt. I ; or, An. de Ch. et de Ph. t. 

 72, p. 225. 



