Quantity of Radium in Rocks and Minerals, lye. 147 



by (1). It is not improbable that the higher results in these 

 two cases are due to a continuous and appreciable emanation 

 loss from preparations oil the kind. 



Tests of the reagents used in the foregoing experiments 

 were made. The carbonates were, indeed, from the same 

 stock as had been used in the solution experiments on granites 

 and andesites, and had been already several times tested by 

 the solution method, yielding inappreciable or negligible 

 traces of radium. Yet, owing to the more searching nature 

 of the new method, I thought it advisable to again test the 

 fusion mixture. 



(1) Twenty-five grams of the mixed alkaline carbonates 

 were fused and heated to the highest temperature of the 

 furnace. There was no effect upon the electroscope ; or, 

 rather, there was a small negative effect, the normal leak 

 falling slightly. 



(2) Twenty grams of the mixed carbonates were mixed with 

 7 grains of precipitated silica and fused. In this experiment 

 there was, of course, brisk effervescence. The electroscope 

 observed for 21 minutes after admission of the gases showed 

 no change in rate of discharge. 



; (3) An exact repetition of this experiment was made at a 

 later date, when the effects were somewhat different. The 

 rate of discharge before the experiment, which was not very 

 steady, rose, after admission of the gases, 2 or 3 scale-divisions 

 per hour. But there was no further change during three 

 hours. 



(4) In order to test the boracic acid used in some of the 

 experiments, 7 grams of the powder were mixed with 28 grains 

 of the carbonates and fused. The electroscope was in ex- 

 cellent condition, reading 4 scale-divisions per hour, with a 

 slight tendency to an augmented rate just before admission 

 of the gases. After transfer of the gases it rose to 6 per 

 hour in 30 minutes, but then continually fell till in three hours 

 it read 4*8 per hour. It is probable that this effect was not 

 due to radium ; in any case it is negligible. This test involves 

 both the boracic acid and the carbonates. 



The use of borax glass as a substitute for the carbonates 

 having been kindly suggested to me by Professor the Hon. 

 R. J. Strutt, an experiment was carried out in which 

 6 grams of the Blackstairs granite was fused with 24 grams 

 of borax. The leak of the electroscope referable to the 

 granite was in this experiment 34 per hour against 37 per 

 hour with the carbonates. The use of the borax is, therefore, 

 admissible, so far as the indications of this one experiment go. 

 A slight deficiencv of emanation yield, if there is any, would, 



L 2 



