390 



Mr. H. J. H. Fenton. 



[Dec. 10, 



with hypobromite* : if this correction be applied the agreement will 

 be still closer. 



In order to facilitate the interpretation of the results, further 

 experiments were made in the same direction, using mixtures of 

 carbamate and water in simple ratios of their molecular weights. 



Mols. Mols. 

 of of 



carbamate, water. 



(a) '3270 gram am. carb. with 15 '09 grams water, corresponding to 1 : 200 



(b) 0-1836 ;, „ 12-71 „ „ 1 : 300 



(c) 0-1307 „ „ 12-06 „ „ 1 : 400 



(d) 0-1042 „ „ 12-02 „ „ 1 : 500 



After standing for some days under similar conditions the following 

 results were obtained : — 



c.c. of N (corr.) Theory for total 



obtained. nitrogen. Hydration. 



(a) 82-02 93-80 0*7487 



(b) 47-29 52-66 7962 



(c) 34-57 37-49 '8447 



(d) 28-62 29-89 0-9156 



Another experiment was made in which the ratio of the molecular 

 weights was nearly 1 : 1, namely, 0*2614 gram ammonium carbamate 

 with 0*0632 gram water. After standing for two days, 49*52 c.c. 

 nitrogen (corr.) were obtained — theory for total nitrogen requiring 

 75*0 c.c. The hydration was therefore 0*3187. 



It follows from the above results that the hydration is a function of 

 the number of water molecules present. So far the minimum hydra- 

 tion corresponds to the case in which the substances are present in 

 about equal molecular proportions, and is in this respect analogous to 

 the combination of iodine with hydrogenf and of phosphorus trichlo- 

 ride with chlorine. J From analogy it was to be expected that the 

 hydration would again increase as the ratio of the ammonium carba- 

 mate molecules to those of water increased ; but the experiment 

 cannot be made under the same conditions as those above, since with 

 any appreciable excess of the carbamate the water is insufficient to 

 completely moisten the solid. 



III. Influence of Temperature. 



The above results may be taken as representing the phenomena 

 which occur at about 20 — 22° C, from which the temperature varied 

 but little throughout the experiments. 



* Russell and West, " Chem. Soc. Jour.," 27, 749. 



f Lemoine : " Equilibres Chimiques entre l'Hydrogene et l'lode Gazeaux," 

 "Ann. Chem. Phys." [5], xii, 145. 



X Wurtz, "Comptes Rendus," lxxvi, 602. 



