160 Miscellaneous Intelligencp. 



small white crystals formed, whicli were repeatedly washed witli 

 water, and dried. Tliese, heated above 212°, first fuse, then boil 

 up, and detonate vehemently with a cracking noise, and a purplish 

 flame, resembling that of cyanogen. The residue is cyanuret 

 of silver, which, by continued ignition in the air, becomes metallic 

 silver. In close vessels, mercury sublimes during the experiment. 

 Muriatic acid disengages hydrocyanic acid from the crystals which, 

 driven off by heat, is succeeded by strong odour of chlorine ; on 

 evaporation chlorides of silver and mercury remain. Solution 

 of the crystals mixed with muriate of baryta, filtered and evapo- 

 rated, yields a saline mass, containing octoedral crystals of ni- 

 trate of baryta. Alcohol also extracts from it cyanuret of mer- 

 cury ; consequently, the original crystals are a compound of 

 cyanuret of mercury and nitrate of silver. 



This substance is difficultly soluble in cold, but plentifully in 

 hot water ; it crystallizes in large transparent prisms, like those 

 of nitre. Alcohol dissolves it as much as water does. It is so- 

 luble in boiling hot nitric acid, without decomposition. Alkalies 

 precipitate cyanuret of silver from its solution, mixed also with 

 sub-nitrate of mercury. Repeated solution in pure water effects 

 a similar decomposition, to a slight extent. Heated below 212° 

 they lose water, and become opaque, without altering in form ; 

 100 parts gave off 7.Q of water. 



To determine the quantity of silver in the compound, one 

 gramme was treated with excess of muriatic acid, carefully evapo- 

 rated to dryness, and the corrosive sublimate expelled by heat, 

 0.32 of a gramme of fused chloride of silver remained, equal to 

 0.2588 of oxide of silver, or 37.96 per cent, of nitrate of silver. 

 The cyanuret of mercury was ascertained by dissolving 0.67 of 

 the crystals in hot water, precipitating the crystals by Chydro?) 

 cyanic acid, filtering, and evaporating to dryness, to expel the excess 

 of acid and the nitric acid, 0.36 of pure cyanuret of mercury 

 remained^ 53.74 per cent. Hence, 100 parts consist of 



Nitrate of silver . . . 37.96 — 1 atom 



Cyanuret of mercury . . 53.74 — 2 



Water 7.60 — 8 



Tills compound must be regarded as a true saline substance, in 

 which nitrate of silver acts as acid, and cyanuret of mercury as 

 base ; and the existence of water in it, a substance possessed by 

 neither of its elements in a separate state, affords additional 

 reason for ranking it among salts. 



M. Wohler then endeavoured to form other similar compounds 

 of nitrate of silver with metallic cyanurets. Newly precipi- 

 tated cyanuret of silver, boiled in solution of nitrate of silver, 

 dissolved slowly but completely. As the temperature fell below 

 the boiling point, there were deposited white acicular crystals in 



