SECTION III., 1910. [67] Trans. R.S. C. 
VIII.—On the Influence of Acids and Salts on the Amount of Emanation 
liberated from a Solution of Radium. 
By A.S. Eve AND D. McINTosx. 
(Read 28th September 1910.) 
In making determinations of the amount of radium in solutions, 
it is necessary to ascertain, by blank tests, whether the acids and other 
substances employed are themselves free from radium. Thus Joly has 
found HC1 to contain so much radium as to necessitate redistillation. 
The writers, during some investigations, found that a barium 
chloride solution was radioactive, and have, therefore, examined some 
salts of barium, reported to be chemically pure. 
These were dissolved in distilled water and the radium contents 
tested by the amount of emanation expelled on boiling. The results 
are given in terms of billionths (101?) gram of radium per gram of 
the salt named :— 
ES coriuiirin CVORIGG <h-.teede ch tasaee eta tors Stas eons 2.84 
Banni VOrORIG an 4. $a. 0) EE sae: 0.11 
BariumayNibraterch «psu cakes. 4 crete ato a eat 0.36 
Thus it is clear that these substances contain about as much 
radium as specimens of rocks or soils from the earth’s surface. The 
radium is probably separated from witherite with the barium in the 
process of extraction. 
Great care is necessary in the case of measurements of minute 
quantities of radium, in the event of chemical treatment with a barium 
salt. For example, a solution of barium chloride was found to contain 
500 times as much radium as sea water. 
In some cases the writers found that the emanation freed by pro- 
longed boiling was less than that known to be actually present. Some 
experiments were, therefore, made to test this important point. 
Three cubic centimetres of a standard solution of radium bromide 
were taken and added to 1,320 cm® of distilled water. After shaking, 
the solution was divided equally between six new clean flasks, so that 
each contained 0°78 x 10°° grams of radium and a trace of HC1 from 
the standard solution. Two of these flasks were kept as blanks, whilst 
to the other four were added respectively, 1 drop H,SO,; 10 cm* 
H,SO,; 10 cm’? Ba C1, (10%), and 1 em° H;SO,; 1:4 grams Ba SQ,. 
The solutions were sealed for a month and then tested in the usual 
way by collecting the emanation and introducing it into an electro- 
scope. The results obtained were almost identical, whether the solu- 
