388 



Mr. H. J. H. Fenton. 



[Dec. 10, 



I. Influence of Time. 



Weighed quantities of ammonium carbamate were dissolved in 

 water and the solutions made up to a definite volume. Measured 

 portions were then withdrawn and examined at stated intervals by 

 treatment with sodium hypochlorite and sodium hydroxide, care being 

 taken to employ approximately the same quantities of reagents for 

 each experiment of the series. The times were reckoned from the 

 moments of complete solution of the salt. 



6 28 73 grams ammonium carbamate were dissolved in water — the 

 solution made up to 100 c.c. and 5 c.c. (corresponding to 0*31437 gram 

 of carbamate) taken for each experiment. Theory for total nitrogen 



= 90-20 c.c. 













c.c. of Nitrogen 





Minutes. 



Intervals. 



(corrected). 



Hydration. 



5 



... 1 .... 



.... 54-16 



-2008 



10 , 



... 2 .... 



. . . . 56 71 



2575 



20 , 



... 4 .... 



.... 60-37 



-3386 



40 



... 8 .... 



.... 66-04 



... '4644 



60 



... 12 



.... 68-60 



-5211 



100 



... 20 .... 



.... 71-44 



. , '5842 



120 . , , 



... 24 .... 



.... 72-08 



, , . -5983 



160 



... 32 . . . . 



.... 72-72 



. . . -6125 



After a further interval of about 24 hours, 72*28 c.c. of nitrogen 

 were evolved. Similar experiments were made with a weaker solu- 

 tion, namely, one containing 4'8781 grams of ammonium carbamate 

 in 250 c.c. ; 10 c.c. were taken for each determination, corresponding 

 to 0*1951 gram of carbamate, and to a total of 55*98 c.c. of nitrogen. 







c.c. of Nitrogen. 





Minutes. 



Intervals. 



(corrected). 



Hydration. 



5 



.... 1 .... 



.... 35*09 



, , 0-2536 



10 , , 



.... 2 .... 



.... 38-72 



... 0*3833 



20 



.... 4 .... 



.... 40-91 



. . . -4615 



40 



.... 8 .... 



.... 43-20 



. .. 0-5434 



60 



.... 12 .... 



.... 45-70 



. .. 0-6327 



120 , ;*. 



... 24 . . . . 



.... 47-47 



... 0-6960 



220 



. . . . 44 



47-57 ..... 



... 0*6995 



After about 24 hours 47*96 c.c. of nitrogen were obtained. 



It is evident from these results that the action, which proceeds 

 rapidly at first, becomes progressively slower, and finally reaches a 

 limit short of complete hydration. 



The time required to reach a determinate state of hydration is 

 evidently greater for a strong solution than a weak one, i.e., decreases 

 as the relative number of water molecules increases. 



