). 
594 Mr Lamplougli, On the determination of the rate of 
From Fig. 4, which gives the rates of evolution of gas plotted 
in terms of the amounts of gas evolved, it will be seen that no 
simple law expresses the connection between the rate of reaction 
Fig. 4. 
and the amount of urea left undecomposed. The rate of reaction 
reaches a maximum value and then gradually diminishes. 
This result is in accordance with the fact that the change is 
complex, the number and nature of the products depending on the 
relative concentrations of the reacting substances. 
The action of sodium hypochlorite on ammonium chloride, 
and on ammonium carbamate (in the latter only the nitrogen 
of the ammonium group being liberated — cp. Fenton, J. G. S. 
1879, T. 12) was found to be so nearly instantaneous as to be 
incapable of measurement by this method. Urethane was not 
attacked by sodium hypochlorite, but on reaction with sodium 
hypobromite all the nitrogen was immediately given off. 
Nickel Carbonyl and Iodine. 
At the suggestion of Mr H. O. Jones, an attempt was made to 
investigate the mechanics of the reaction between nickel carbonyl 
and iodine. These substances react together according to the 
equation 
Ni (CO) 4 + I 2 = Nila + 4CO, 
