34 On the Rapid Estumation of Urea. 
gaseous condition, and its bulk determined either indirectly or 
directly, the volume of nitrogen produced thus serving as a 
measure of the urea from which it was derived. 
The equation which expresses the change just referred to is the 
following :— 
CO’N,.H,+3 (NaBrO) +2 (NaOH)=3 NaBr + Na,CO, 
ee Sodic 
Urea Hypobromite J 3H,O 4+I2N, 
The use of calcic hypochlorite, or solution of “ chloride of 
lime,” in effecting a similar decomposition was pointed out by 
Dr. E. W. Davy,* and it has been recently shown by Yvont that 
the hypochlorite used by Davy is more effective than the sodic 
hypochlorite, but it does not evolve the whole of the nitrogen and 
is irregular in its action. Knop, and after him Htifner,t and many 
others, have shown that the sodic hypobromite is greatly to be 
preferred to any of the hypochlorites, as the decomposition of 
urea is almost complete, and progresses regularly and rapidly 
without the aid of heat; hence I use the hypobromite as the 
basis of the plan of operating now to be described, and in this 
respect agree with Hiifner, Russell and West, R. Apjohn, Blackly, 
(Dupré, and with Simpson and O’Keefe)§ in the methods they 
have proposed for urea estimation. 
The different methods devised by the above-named chemists 
all serve for the direct measurement of the volume of nitrogen 
evolved during the action of the hypobromite on urea, and involve 
the use of specially graduated tubes for the reception and measure- 
ment of the pure gas. My plan is essentially different, as the gas 
evolved, which is scarcely soluble in water,|| is made to displace 
its own volume of that liquid, and the latter is then easily measured 
in any ordinary vessel, such as a tall and well graduated drachm 
measure. 
The apparatus may be most conveniently described as consisting 
of two distinct parts—A, the generating vessel (see annexed wood- 
* Journal of the Royal Dublin Society and Phil. Mag. [4] Vol. vii., p. 403. 
+ Journal de Pharmacie et de Chimie. [4] Vol. xxiv. 
t Journal fiir Praktische Chemie. [2] Vol. iii, p. 1. 
§ Published since this paper was read. 
|| According to Bunsen, water dissolves only 0°01478 of its volume at the mean tem- 
perature and pressure (Bunsen’s Gasometry, p. 286). 
