234 PROCEEDINGS OF THE AMERICAN ACADEMY. 



I. 0.1508 gram <>f the Btibstance gave by the method of C'arius 0.1494 



gram of argentic bromide. 

 II. 0.3041 gram of the substance gave 20.2 c.c. of nitrogen at a tem- 

 perature of 18°. G and a pressure of 760. 1 una. 



iiiit.il for I mi 1. 



\> \ I. II. 



Bromine 12.11 42.18 



Nitrogen 7.37 7.04 



In view of the great tendency of cyanamides to polymerize, it was 

 thought safer to determine the molecular weight of tin- body * by the 

 method of freezing a benzol solution, which gave the following results: — 



0.375 gram of the substance dissolved in 16. "Jo grams of benzol produced 

 a depression of U J .28 in the freezing point. 



Calculated for (C.|I,llr..N< N Found. 



.Molecular weight 380 837 



There can be no doubt, therefore, that the substance is really 

 (C 6 H 4 BrCH 8 ) 3 NCN. 



PROPERTIES OF DlPAKABROMr.KNZYI.C VAN AMIDE. 



The substance crystallizes from benzol in sheave- of white crystals 

 Bhaped like the blade of a lancet, sometimes united laterally into group- 

 with comb ends. It melts at 133°. It is freely soluble in benzol, chlo- 

 roform, acetone, or acetic ester; soluble in toluol; slightly Boluble in cold 

 ethyl or methyl alcohol or glacial acetic acid, freely soluble in tin ae 

 solvents when they are hot ; slightly soluble in ether, carbonic disulphide, 

 or in hot or cold water; essentially insoluble in Iigroine. It is slowly 

 decomposed by cold strong sulphuric acid: apparently unaffected by 

 hydrochloric acid or nitric acid in the cold. The best solvent for it is 

 hot alcohol. 



In order to see if it could form a chloride, a portion of the dipara- 

 brombenzylcyanamide was dissolved in anhydrous benzol and saturated 

 with <\ry hydrochloric acid gas. No precipitate was formed even after 

 the mixture had stood for two week-, and on evaporating off the benzol 

 the original substance was recovered unaltered. It would seem from 

 this experiment that the diparabrombenzylcyanamide cannot unite with 

 hydrochloric acid. 



* Thia work was done before the appearance of Wallach'a statement thai <H- 

 Bubstituted cyanamides show no tendency to polymerize. 



