SEcTION III, 1916 [57] TRANS. R.S.C: 
On the Release of Radium Emanation from Water at Different Tempera- 
tures by the Bubbling Method. 
By J. Moran, M.Sc. 
Presented by Pror. A. S. Eve, D.Sc., F.R.S.C. 
(Read May Meeting, 1916) 
Introduction 
Two methods are in use for the determination of the amount of 
radium in a radium solution by the emanation method— 
(a). Expel all the emanation from the solution by boiling, seal up 
the flask in an air-tight condition and allow to stand for a definite 
interval, say a week or more, and then drive off the accumulated 
emanation by boiling, collecting the emanation over water in a col- 
lecting-apparatus. The fraction of the total emanation accumulated 
in the interval is obtained from Rutherford’s tables on the growth of 
emanation. The emanation is passed into the electroscope, and tested 
in the usual way, by the rate of fall of the gold-leaf. 
or, (b). Take the cold solution, bubble air through it until the 
emanation is expelled as far as bubbling will expel it, then bubble 
air through the solution at a constant rate, passing it into and out of 
an ionisation chamber connected with an electroscope. 
Wright and Smith, in the Philippine Journal of Science for Feb., 
1915, published results of an investigation of the question: 
“Is the standard solution put into the so-called steady state by bub- 
bling air through the solution for a periof of from two to three hours, or 
is it necessary to boil the solution? If the bubbling of air through the 
cold solution does not take out the emanation as fast as it is formed 
what per cent is taken out by the process ?” 
They claimed to have shown that considerably more emanation 
is obtained by bubbling air through the boiling solution than through a 
cold one. It would appear from their results that radium emanation 
distributes itself in definite proportions between the water and the 
air-space above it in the case of a radium solution in a vessel, and 
that more of the emanation is removed as the temperature rises, 
reaching a maximum at boiling temperature. 
Object. The object of this experiment was to investigate the 
release of radium emanation from water at different temperatures by 
