392 



Mr. H. J. H. Fenton. 



[Dec. 10, 



5 c.c. of A gave 35 '54 c.c. N (corr.) 

 10 „ B „ 38-10 

 50 „ C „ 40-85 



Equal volumes of another solution were examined at intervals, with 

 the following results : — 



After 5 minutes 67 '94 c.c. N (corr.) were evolved. 

 „ 40 „ 66-73 

 „ about 3 hours 62'52 „ „ 



„ 24 „ 62-28 



These results indicate that normal ammonium carbonate undergoes 

 dehydration into carbamate when in solution, and that the dehydra- 

 tion is greater as the relative number of water molecules is less. 



The instability of normal ammonium carbonate, and the difficulty 

 of obtaining it free from adhering impurities has, for the present, 

 prevented me from making more extended observations on this part 

 of the subject. It seems not unlikely, that if the same relative 

 number of molecules could be started with, the same equilibrium 

 state between carbamate, carbonate, and water, would be arrived at 

 for the same temperature, whether ammonium carbamate or normal 

 carbonate were initially taken — that is, that the curves of hydration 

 and dehydration would meet at the same point. I hope before long to 

 be able to make experiments in this direction. 



Since there is this tendency for ammonium carbonate to become in 

 part dehydrated in aqueous solution, and for the system to come to a 

 state of equilibrium where the carbamate and carbonate co- exist, it 

 seems probable that the hydrolysis of urea, under the action of 

 ferments, &c, may be less simple than is usually represented — that 

 the reaction, instead of being simply CO(]S"H 2 ) 2 + 2H 2 0=CO(ONH 4 ) 2 , 

 may be of the following type : — 



rcCO(NH 2 ) 2 + (2rc-m)H 2 0=mCO(NH 2 )(ONH 4 ) + (n-m) CO (ONH 4 ) 2 . 



I propose to attack this subject by the same method as those 

 employed above. 



By means of the actions of sodium hypochlorite and hypobromite 

 it is evidently possible and easy to estimate quantitatively urea, 

 carbamic acid, and ammonia, when all are present in the same 

 solution. 



Take two equal portions of the solution to be examined, treat one 

 with sodium hypobromite, and let the volume of nitrogen evolved 

 (corrected for loss) =Y 1 . 



Treat the other portion with sodium hypochlorite, and let Y 2 = 

 volume of nitrogen obtained. 



Act upon the residue from this last experiment with sodium hypo- 



