contained in Coal-gas Naphtha. 127 



blue reaction. Nicotine, coniine, chinoline, sinnamine pro- 

 duce noeffecton the hypochlorites; naphthalidam gives a feeble 

 violet tint, which cannot be mistaken for the cyanol reaction. 



As a further test for cyanol, Runge has noticed the property 

 its salts possess, of imparting an intense yellow colour to fir- 

 wood and the pulp of the elder-tree. The base itself does not 

 possess this power. This reaction is also shown by the acid 

 solutions of crystalline, aniline and benzidam. In general, 

 however, very little weight is to be attached to such coloriza- 

 tions ; the salts of leucol, which, according to Runge, do not 

 possess this property, produce it notwithstanding after some 

 time; the salts of coniine, sinnamine and chinoline also, tinge 

 fir-wood slightly yellow, and the salts of naphthalidam pos- 

 sess this property perhaps in a still higher degree than even 

 the salts of cyanol. As a characteristic of aniline Fritzsche 

 alludes to its behaviour with an aqueous solution of chromic 

 acid. This affords, both in aniline, and solutions of its salts, 

 a precipitate, which, after the concentration of the supernatant 

 liquor, assumes a green, blue, or black colour. Crystalline, 

 benzidam and cyanol, give the same reaction. 



Naphthalidam and its salts effect the same change with 

 chromic acid, but the other before-mentioned bases do not. 



The peroxide and protoxide salts of iron are decomposed 

 by cyanol with the separation of hydrated peroxide or prot- 

 oxide of iron. In the same manner alumina and oxide of 

 zinc are separated from the sulphates of these bases. 



Cyanol produces in a solution of sulphate of copper a pale 

 green crystalline deposit, which is not altered by a temperature 

 of 212°, and is very probably a double compound of sulphate 

 of copper and cyanol. This precipitate is also occasioned in 

 chloride of copper, which, if in excess, becomes quickly black. 



Similar double compounds are produced in solutions of 

 chlorides of mercury, platinum, palladium and gold. The 

 double salt of mercury is white, that of platinum or palladium 

 a fine orange-yellow. The precipitate which occurs in the 

 gold solution is reddish-brown, of the colour of ferrocyanide 

 of copper. When chloride of gold is mixed with hydro- 

 chlorate of cyanol, there is obtained a yellow deposit, which 

 speedily becomes of a dirty reddish-brown colour. 



Cyanol throws down from solutions of chloride of tin and 

 chloride of antimony a copious curdy precipitate. Neutral 

 and basic acetate of lead are only rendered turbid. 



Cyanol produces no precipitate with nitrate of silver or the 

 oxides of mercury, and the salts of nickel, cobalt, manganese 

 and chromium, chlorides of barium and calcium, sulphate of 

 magnesia, cyanide, ferrocyanide and sulphocyanide of potas- 

 sium. 



