Transactions of The Royal Society of Canada 
SECTION III 


Shee lil * _ DECEMBER 1016 VoL. X 


A Comparison of Radium Standard Solutions —Continued. 
By J. Moran, MSc. 
Presented by Prof. A. S. Eve, D.Sc., F.R.S.C. 
(Read May Meeting, 1916). 
PRELIMINARY. 
In a set of experiments conducted during the session of 1915-1916, 
an attempt was made to determine as accurately as possible the values 
of the radioactive standard solutions in use at this university. The 
comparison was made by means of a Washington Standard solution. 
A litre of this was obtained by Eve in Sept. 1914, from Satterly 
of Toronto University. It was certified to contain 9-15 X 107! 
grams of the radium element per c.c., and to be correct with the 
International Standard to within one per cent. This consists of 
21-99 milligrams of pure radium chloride, prepared by Mme. Curie, 
and preserved at Sévres, France. 
The standard solutions compared were the Rutherford-Boltwood 
strong and the Rutherford-Boltwood weak solutions. These solution 
standards were prepared by Boltwood from a known amount of 
radium bromide, determined by Eve by the y-ray method. They 
were in the ratio of 100 : 1, one containing 1-57 X 10 and the other 
1-57 X 10° grams of radium per c.c. The values assigned to these 
standards depend on the value of the Rutherford-Boltwood solid 
standard by which these solution standards were originally stand- 
ardised. This solid standard was prepared in 1903, at McGill Uni- 
versity, Montreal, and consisted of 3-69 milligrams of pure radium 
bromide, bought from Dr. Giesel of Germany, and presented to the 
University by Sir William Macdonald. It is now at Manchester 
University, England. Later on direct determination with the Inter- 
national Standard by Rutherford, and also by a number of cross- 
determinations with secondary standards which had also been com- 
pared with the International or the Vienna Standard, the solid 
Sig. 1, Sec, III 
