84 THE ROYAL SOCIETY OF CANADA 
We thus have— 
Rutherford—Boltwood Weak : Washington :: 96-4 : 100. 
Rutherford—Boltwood Strong : Washington :: 97-3 : 100. 
SUMMARY. 
(1) The object of this experiment was to re-determine the values 
of the Rutherford—Boltwood weak and strong solution standards. 
They were prepared in the first place by means of the Rutherford- 
Boltwood solid standard, now at Manchester University, England, 
and this solid standard was found by Rutherford to be 4-9% low. 
If no error was made in their preparation we should expect the solution 
standards to come out similarly. The results of last session showed— 
Rutherford—Boltwood Weak : Washington :: 98 : 100. 
Rutherford—Boltwood Strong : Washington :: 96 : 100. 
This time the re-determination showed them to be— 
Rutherford—Boltwood Weak : Washington :: 96-4 :100. 
Rutherford-Boltwood Strong : Washington :: 97-3 : 100. 
(2) In the work of last year it appeared that the radium bromide - 
solutions deteriorated with -each boiling. Also, that if a sufficient 
amount of HC1 were added the solution seemed to recover its normal 
emanating power. At that time no pure HC1, free from radioactive 
matter, was available. It was estimated at that time after testing a | 
portion of HC1 from the same bottle as was used for the experiment, 
that a part of the increase in value was due to radioactive matter in 
the HC1 itself. The work of the present year, with pure HC1 free. 
from radioactive matter, proves that the whole of the increase must 
have been due to the radioactive matter in the HC1. The excess then 
got was evidently due to lack of refinements in the apparatus. Also 
the boiling effect which seemed to be apparent last year was traced 
to the same cause. 
McGill University, Montreal. 
May 2nd, 1916. 
