[moran] radium standard SOLUTIONS 31 



solution in the qualititave experiment, mentioned in the first part 

 of this section. In the first trial when acid was added, the "figure 

 of merit" went above the normal, due obviously to an excess of acid 

 added, which had sufficient radioactive matter in it to account for the 

 abnormal rise. In the second case, it did not reach the normal value 

 when 2% was deducted for the radioactive matter in the acid added. 

 Apparently all the radium had not been re-dissolved in the second 

 case. These sets of experiments also established the fact that a 

 radium bromide solution deteriorates with boiling, and that, because 

 of this, too great reliance cannot be placed on the result of a single 

 test. Every solution tested showed a steady decline, even after 

 adding the acid. In all, about 70 tests were made. 



A similar solution was prepared and used by Dr. Eve in November 

 1908. This was also tested, and showed only 45% of the strength 

 obtained for the Washington standard. It thus appears that such 

 solutions, which have been boiled a number of times and then allowed 

 to stand very long, are not reliable, and a new preparation should 

 be used for each set of experiments. 



The work showed that the weak solution of the Rutherford- 

 Boltwood standard is to the Washington standard solution in the ratio 

 of 98 : 100. The results obtained in the comparison of the strong and 

 the weak solutions of the Rutherford-Boltwood standard showed 

 the strong 2% lower than the weak, or strong: weak :: 98 : 100. 

 This may be considered a fair agreement, and indicates but slight de- 

 terioration with time. 



We thus have — 

 Rutherford-Boltwood, strong solution : Washington = 96 : 100 

 Rutherford-Boltwood, weak solution : Washington = 98 : 100 



A more complete set of experiments will be carried out later, 

 and the exact effect of successive boilings further determined. 



In closing, the writer has much pleasure in expressing his appreci- 

 ation for suggestions given by Professor Eve, and also by Dr. Mcin- 

 tosh, in the course of this work. 



SUMMARY. 



1. The object of this work was to determine the accurate value 

 of the Rutherford-Boltwood standard solution at McGill University 

 by comparison with the Washington standard solution. The former 

 was compared initially with the Rutherford-Boltwood solid standard 

 which is known to be 4-9% too low on the International. If no 



