1885.] Limited Hydration of Ammonium Carbamate. 389 



II. Influence of Mass. 



8*3272 grams of ammonium carbamate were dissolved in water and 

 the solution made up to 100 c.c. (Solution A.) 



25 c.c. of solution A were made up to 50 c.c. (Solution B.) 



25 c.c. of solution A were made up to 250 c.c. (Solution 0.) 



The relative strengths were therefore A : B : C : : I : J : to- 



The solutions were set aside for four days in carefully stoppered 

 flasks and under similar conditions. Volumes of each solution which 

 corresponded to equal masses of ammonium carbamate were then 

 withdrawn — namely, 5 c.c. of A, 10 c.c. of B, and 50 c.c. of C, repre- 

 senting 0*41636 gram of carbamate — and examined by the hypochlo- 

 rite method in the usual way. 



5 c.c. of A gave 95* 73 c.c. N (corr.). 

 10 „ B „ 99 -99 

 50 „ C „ 110-60 „ 



In order to be certain that the equilibrium state had been arrived 

 at, the same solutions were again examined after a further interval of 

 two days, when 



5 c.c. of A gave 95 '35 c.c. N (corr.). 

 10 „ B „ 99-96 

 50 „ C „ 110-83 



showing that the limits had been reached in the former experiments. 

 These numbers correspond to the hydrations — 



A -5963 



B -6735 



C 0-8550 



In order further to confirm these results, the residues from the last 

 experiments, after the completed action of the hypochlorite, were 

 treated with sodium hypobromite in order to estimate the nitrogen 

 remaining as carbamate. 



Residue from A gave 22 '02 c.c. N (corr.). 

 „ B „ 17-50 



., „ 8 *01 „ 

 making the totals — 



A 117-37 c.c. N (corr.). 



B 117-46 . „ 



C 118-84 



theory for 0'41636 gram ammonium carbamate requiring 119'46 c.c. 

 There is always a loss of about 8 per cent, of nitrogen in estimations 



