August, '19] WOLGUM AND ROUNDS: LIQUID HYDROCYANIC ACID 301 



Table 1. Table Representing the Results of Experiments on Stratification 



I Cloudiness in sample formed by diluting 96 per cent hydrocyanic acid to make a 50 per cent 

 solution. 



which the liquids were brought together slowly, stratification occurred. 

 One series of bottles left undisturbed for several weeks showed distinct 

 stratificiation throughout this period. If, however, the materials 

 were brought together violently and thoroughly shaken stratification 

 was not produced. 



When liquid hydrocyanic acid was allowed to flow slowly into water 

 near the surface level it rose to the surface and did not mix freely with 

 the water. Ultimately a layer or stratum was formed between the 

 heavier lower liquid and the lighter upper one. When water was 

 added slowly to liquid hydrocyanic acid it flowed through the liquid 

 to the bottom of the bottle forcing the lighter chemical to the top, 

 and showed a distinct stratum between the two liquids. In some 

 cases this stratum between the two liquids was transparent and 

 detected only by close examination, or agitation of the bottle. In 

 other cases a cloudiness or milky appearance was observed when water 

 and hydrocyanic acid were mixed and this precipitate ultimately 

 collected in the middle layer to which it gave a whitish gelatinous 

 appearance. (PI. 14, fig. 1.) When allowed to stand in bottles un- 

 disturbed for a short time a vigorous shaking was necessary to break 

 up this layer. 



This milkincss occurcd only with liquid hydrocyanic acid taken 

 from galvanized iron drums. A chemical examination of the acid 

 taken from drums showed it to contain traces of zinc in solution whereas 

 the liquid hydrocyanic acid which produced no precipitate had been 

 in glass containers and upon examination was found to contain no 

 zinc. Since zinc was in solution in the liquid hydrocyanic acid and 

 since zinc compounds with cyanogen arc known to be in.soluble in 

 water, it woukl seem apparent that tlie precipitate formed was some 

 compound of this metal. The presence of a gelatinous precipitate 



