254 Scientific Proceedings, Royal Dublin Society. 
In reviewing these figures Hve states that it is safe to 
conclude that sea-water does not contain more than 0:0006 x 10-¥ 
grams radium per gram. 
In April of the present year a friend sent me from Valencia, 
Co. Kerry, a sample of sea-water collected in the harbour at 
flood-tide. A very large volume of water enters this extensive 
harbour at each flood ; and as there are no large rivers along the 
coast, water taken at the harbour mouth may be regarded as free 
from impurities derived from the shore. The quantity sent to 
me (in a stoppered glass bottle which I had transmitted, specially 
cleansed, for the purpose) was 2450 ccs. This was evaporated on 
the water-bath to about 1200 c.cs., with every precaution against 
contamination, and in a part of the laboratory in which radioactive 
preparations had never come. ‘The radium determined in this 
Valencia sea-water was 0°0356 x 10°” grams per gram. ‘The 
apparatus and mode of extraction I was using at this time were 
closely similar to those developed by Strutt as described in his 
paper (loc. cit.). The readings of the electroscope were standardised 
by the emanation from Joachimsthal pitchblende, a portion of 
which I had analyzed for the uranium. 
This determination, showing more than ten times the amount 
of radium given in any evaluation known to me, I naturally 
regarded as requiring confirmation. 
In the month of May I received from Mr. 8S. W. Kemp, of the 
Trish Fishery Department, 2800 c.es. of sea-water taken in the Irish 
Channel a few miles to west of the Isle of Man, lat. 53° 53’ N., 
long. 5° 16’ W. This also was transmitted in bottles which I 
had supplied for the purpose. The water was evaporated down 
to about 800 ¢.cs., and when investigated yielded only 0:0038 x 10-” 
grams per gram. This figure seemed to support sea-salt determina- 
tions; but I was so convinced of the genuineness of the first result 
that I provisionally concluded a real difference to exist between 
near-shore and more open-sea samples of water. I had, indeed, 
changed the mode of extraction of the emanation, substituting 
a method in which ebullition proceeds in a partial vacuum, 
and at its conclusion the space above the liquid in the flask is 
completely filled with distilled water, thereby securing that 
every trace of emanation is displaced into a receiver, from which 
it is transferred into the electroscope. I had found by comparative 
