Chemistry and Physics. ae 
glass vessel, is absolutely free from minimal quantities of foreign 
substances, as e. g. sodium salts, silica, etc. For my own part I 
am rather inclined to think that absolutely pure water, if it could 
4 > 
gin C. or below. 5 
this it is added that it must be acknowledged “that the ice 
masses of the glaciers are liable to contraction at temperatures 
below their melting point.” 
closed rine; the result reached is the same as that obtained in - 
a different way by Dr. Buchanan of the Challenger. Dr. Petters- 
son concludes that ocean-water is divided by freezing, not to 
pure water and a more or less concentrated solution of ordinary 
brine in chlorides, The extraordinary variation both in saltness 
however, ‘from a thermic point of view, is not entirely concluded 
With the solidification of the sea-water, by which it is divided 
into ice, solid eryohydrates, and liquid brine containing dissolved 
salts; for on further sinking of the temperature, still unfrozen 
ctyohydrates will be solidified and develop — — the whole 
8S, at a sufficiently low temperature is a solid roc of mye oo 
