J oLy— On the Radium-Content of Deep-Sea Sediments. 289 
I owe these to the kindness of Sir John Murray, F.r.s. For a 
specimen of Globigerina Ooze, brought up in trawling, I have to 
thank Mr. 8. W. Kemp, of the Irish Fishery Department. 
Although these materials have been in my possession for some 
months, most of the experiments are of recent date, and where two 
are recorded, the second is, in every case, a recent re-examination 
of the same material. ‘The reason for this postponement was my 
desire to arrive at a fuller knowledge of the most reliable condi- 
tions of investigation before using up material of such value. In 
the process of acquiring experience of the experimental difficulties 
involved, various methods of extracting the emanation were tried. 
According to the nature of the substance these methods have been 
applied in the observations on deep-sea deposits. It would be 
out of place to consider these methods here, and their relative 
merits. A short list has to be given, however, of such as have 
been used in obtaining the data which follow. A reference letter 
attached to the experiment will then suffice to show the mode of 
extraction adopted. 
(A.) The substance is fused in a platinum crucible with the 
mixed carbonates of sodium and potassium, and the melt leached 
in hot water. This is filtered, and the filtrate is closed as the 
alkaline solution. The residue is treated with hydrochloric acid, 
and closed as the acid solution. If the acid solution contains or 
develops a precipitate, this is filtered out and re-fused with the 
carbonates, the melt being treated as before, i.e. divided between 
the alkaline and the acid solutions. Both solutions are subsequently 
examined for radium. In a variation of this method the melt 
alter leaching is acidified, and but one acid solution closed. 
(B.) The substance is boiled in HCl, and the filtered solution 
enclosed the requisite time. ‘Ihis is applicable only when there is 
good reason to believe that the insoluble part contains but little 
radium. 
(C.) The substance is fused with the carbonates, and the 
leaching effected as in (A). The thoroughly softened and diffused 
melt and solution are enclosed in the one flask without further 
treatment. After the lapse of the requisite period it is attacked 
with HCl, and the emanation withdrawn along with the CO, 
evolved in the process of decomposition. Vigorous boiling 
finishes the process of extraction. ‘The arrangement of apparatus 
