152 Selections from Foreign Science. 



12. Though generally of a clear colour it is sometimes obtained 

 of a deeper tint. 



13. When recent it is nearly without odour, but when left in moist 

 air, for two or three hours, it has a faint smell of hydrosulphuret of 

 ammonia; and if the air be very damp it softens a little. It dis- 

 solves abundantly in water, not so readily in cold alcohol, but very 

 readily at high temperatures. Ether dissolves but little, naphtha 

 none. The aqueous solution is, when strong, yellow, when dilute, 

 colourless. 



14. It has all the characters of a neutral salt, except when by 

 time it smells of sulphuretted hydrogen, and then it becomes al- 

 kaline. Acids produce no effervescence with it, except they be- 

 come decomposed, as nitric acid; nor do they cause immediate 

 precipitates. Salts of lime and baryta cause no precipitate. Per- 

 salts of copper, a flocculent yellow precipitate, not undergoing 

 change by time or air ; dilute nitrate of silver, yellow becoming 

 black ; salts of lead and mercury, white precipitates becoming- 

 black ; with per-salt of iron, the solutions become black, and give a 

 black precipitate which becomes white. 



15. The yellow precipitate from copper, heated with a solution 

 of potash, neutralized it, furnishing the usual hydrosulphocyanate 

 of potash of Porret, and depositing a black powder, which ex- 

 amined by heating in a tube, ^-c, proved to be deutosulphuret of 

 copper. When boiled in water only, the same effect takes place, 

 and the copper precipitate gradually produces solution of hydrosul- 

 phocyanic acid and the deutosulphuret of copper. H2nce it appears 

 that the yellow precipitate may be considered as a compound of 

 deutosulphuret of copper and hydrosulphocyanic acid, and for 

 reasons advanced, or to be advanced, M. Zeise considers it as a 

 compound of one proportional of the sulphuret, and two of the 

 acid ; and consequently the ammoniacal salt from which it was 

 formed, as one ammonia, one hydrosulphocyanic acid, with two 

 hydrogen and one sulphur. 



16. The solution of the salt does not change, except when ex- 

 posed to the air, when it deposits crystals of sulphur, and be- 

 comes common hydrosulphocyanate ; the oxygen of the air appear- 

 ing to have taken hydrogen, and set sulphur free : sometimes also 

 it becomes slightly acid. An alcoholic solution of the salt, when 

 heated, is decomposed, and hydrosulpburet of ammonia set free. 

 The solid salt also, by lime, appears to form a little hydrosulpho- 

 cyanate. 



17. Sulphuric or muriatic acid diluted with two parts of water, 

 added to a solution of one part of the salt in four of water, and 

 then mixed with much more water, causes the separation of a 

 translucid, colourless, and oleaginous fluid at the bottom of the 

 mixture, which may be preserved some time therein, but not in 

 pure water; and which may probably be the hydrosulphuretted 



