ELISHA MITCHELL SCIENTIFIC SOCIETY- 55 



2. A similarly prepared tube was placed in boiling water; 

 within five minutes a change to brownish-red was noticed, 

 and the color lapidly darkened with the exposure, 



3. A similarly prepared tube was fitted with cork and 

 tubes, and while it was in the boiling water carbon dioxide 

 was introduced. The changes were noticed very much as in 

 experiment 2; apparently they were slightly delayed rather 

 than hastened. 



4. Into a tube prepared as in 3, hydrogen was passed in a 

 rapid continuous stream. The changes were greatly delayed 

 and no very deep discoloration was obtained. 



5. If experiment 3 is so reversed that the carban dioxide 

 is passed above a cold solution of the cyanide, giving oppor- 

 tunity for its absorption, the change of color is rapid and 

 deep. 



From these experiments the conclusion can be drawn that 

 though carbon dioxide hastens the decomposition of the 

 cyanide, as any free acid would do, yet it is not essential for 

 this decomposition. 

 Chem. Laboratory, U. N. C. 



LEAD CHLOE^SULPHO-CYANIDE. 



R G. GRISSOM. 



This new compound of lead can be easily prepared by 

 acting on lead chloride with a strong solution of potassium 

 sulpho-cyanide. Freshly precipitated and recry.stallized 

 lead chloride was covered with a solution of potassium 

 sulpho-cyanide in excess, and allowed to stand for several 

 days. The liquid was then poured off and the residue 

 treated several times with boiling water until all was dis- 

 solved. This fractional solution was carried out to separate, 

 if possible, substances of different solubility. The fractions 

 rapidly deposited crops of crystals on cooling, but examina- 

 tion under the microscope showed that these crystals were 

 identical in crystalline form. 



Analyses were made as follows : 



.6220 gram, of subs-ance gave 5730 gram Pb SO, or 68.57 per ct Pb 

 1.0280 't » " '•' .7047 " " 0168.55 " " " 



For chlorine and sulphocyanic acid 1.0700 grammes of 



the substance was dissolved in water and precipitated with 



silver nitrate. This was filtered and treated with strong 



nitric acid thus oxidizing the sulpho-cyanide. After dilution 



it was again filtered. The silver chloride was burned and 



the sulphuric acid determined in the filtrate in the usual 



way. 



