ELISHA MITCHELL SCIENTIFIC SOCIETY. 11 



ish crystals, apparently of the first system. These were dried 

 on filter paper and then over sulphuric acid. They contained 

 23.05 per cent, of bromine and 16.65 per cent. CNS. Calculated 

 for PbBrCNS, 23.02 percent, bromine and 16.85 percent, CNS. 



Hydrobromic acid was added to the mother-liquor of these 

 crystals, and on evaporation a crop of clumpy, indistinctly yel- 

 lowish crystals was obtained. These were dried and analyzed, 

 giving 3.46 per cent, of CNS. Calculated 3.56 per cent, of 

 CNS for 8PbBr 2 .Pb(CNS) 2 . 



Lead iodosulphocyanide. — The first attempt at preparing this 

 salt was by adding the excess of potassium sulphocyanide, in 

 solution, to freshly precipitated lead iodide. On washing with 

 hot water lead iodide alone crystallized out. Again sulphocyanic 

 acid was used to dissolve lead iodide, but the double compound 

 refused to form and again the iodide only crytallized out. When 

 equivalent amounts of lead iodide and lead chlorosulphocyanide 

 wore dissolved in boiling water and allowed to crystallize, the 

 iodide crystallized out by itself. Lastly, lead iodide was dis- 

 solved in a strong solution of potassium sulphocyanide. This 

 gave on cooling small glistening nearly white crystals. It is 

 interesting to note in this and other cases where double com- 

 pounds with lead iodide were obtained, that at one stage of the 

 cooling numbers of large, distinct crystals of lead iodide would 

 separate. On further standing and cooling these would entirely 

 disappear and all the erytals would be of the double compound. 



Analysis gave for this compound figures corresponding to 

 57.22 per cent. Pb. Calculated for PbI 2 .3Pb(CNS) 2 , 57.83 per 

 cent, Pb. 



Lead chlorocy ankle. — When lead chloride crystals were cov- 

 ered with a strong solution of potassium cyanide, a heavy and 

 quite insoluble body was formed which, on standing, rapidly 

 changed in color to a purplish brown. This was due to partial 

 decomposition and loss of hydrocyanic acid.* This heavy in- 



"Chemical News, 51, iv 



