604 Mr Lamplough, On the determination of the rate of 
in a state of supersaturation and the law of a unimolecular reaction 
is no longer even approximately obeyed. The reaction therefore 
as measured by the rate of evolution of gas from the still solution 
resembles for a limited range a unimolecular action, and it is this 
resemblance which has been measured by Cain and Nicoll and 
other experimenters. 
Experiments were also performed in which a solution of 
diazobenzene chloride was allowed to decompose, the rate of 
decomposition being measured by the evolution of gas from the 
stirred solution. After a few observations had been taken, the 
stirring was arrested, and the rate of evolution of gas from the 
unstirred solution was measured. It was found in such experi- 
ments that the later observations show a break in the curve such 
as is represented by the line PB in Fig. 9, only a portion of the 
gas liberated by the decomposition being actually evolved, the 
remainder being stored up in the solution in a state of super- 
saturation. After an interval of time the solution was again 
agitated, and within a few seconds the whole of the gas thus 
