1888 - 89 .] 
Meetings of the Society. 
813 
Ocean,” were communicated to the Society, and printed in its Pro- 
ceedings during the period 1885-87. 
Dr Buchan, on presenting the prize, made the following state- 
ment : — 
In our Transactions for 1880 there is a noteworthy paper by 
Mr Buchanan on the “ Compressibility of Glass.” 
The methods hitherto employed for measurement of the com- 
pressibility of solids have usually been indirect , depending for the 
most part on the determination of Young’s modulus by traction, 
flexure, or acoustical processes. This modulus is a function of the 
rigidity and the compressibility jointly, so that the rigidity had to 
be determined independently, say, by torsional methods. Thus the 
values of compressibility hitherto obtained have -been more or less 
uncertain. 
Buchanan’s process is a simple and direct one. He measures the 
linear compression of a rod under hydrostatic pressure, and (assuming 
the material to be isotropic) obtains thus one-third of the compress- 
ibility. 
His apparatus, especially the device by which the ends of the rod 
can be microscopically examined while it is exposed to very high 
pressures, is an ingenious one, and it is easy to work with; so that 
it is to be hoped that he will soon extend his results to a large 
number of the more common solids, for our information on this 
subject is still extremely meagre and unsatisfactory. 
From the results of Mr Buchanan’s experiments on “Ice and 
Brines,” it is shown that the first ice formed on the sea in Arctic and 
Antarctic regions consists of pure ice, retaining, however, a large 
quantity of the residual sea-water in its interstices ; and during the 
winter this enclosed liquor solidifies in the interstices of the crystals 
to ice and cryohydrates, in so far as the temperature and the nature 
of the salts in solution permit. 
Some years previously, Dr Otto JPettersson incidentally remarked, 
in his work on the Properties of Water and Ice , that a thermo- 
meter immersed in a mixture of snow and sea-water, which is con- 
stantly stirred, indicates 28°*8, and therefore we may regard this as 
the upper limit of the freezing and the nether limit of the melting 
temperatures of sea-water. Mr Buchanan’s experiments confirm this 
statement, and he has the merit of applying the fact that ice melts 
in ordinary sea-water at a temperature of from 29°T to 28°-8, 
according to its saltness, to explain successfully the anomalous dis- 
tribution of temperature in Antarctic waters. The warmer and 
denser water of lower latitudes bathes the under surfaces of the 
