VEGA-EXPEDITIONENS VETENSKAPLIGA AliBETEN. 315 



spiral (see p. 269) together with the frozen substance. Thereby 

 we may in some degree account for the extremely low latent 

 heat of the watersamples f (oeean-water from Jan Mayn), but 

 the difficulty still remains to account for the deficiency in 

 latent heat of the following water-samples Yl, V, lY, which 

 were obtained b}^ melting of sea-ice and consequenfh/ only onght 

 to contain suck constituents as are capahle of soJiditication. From 

 sample Yl, which was formed by freezing of sea-water, the 

 liquid brine had been separated previously (see p. 291). We 

 must, however, admit as probable, that even in these cases 

 (Yl & Y) a diminutive part of the sample was kept from 

 freezing, until lower temperatures, as a concentrated brine, 

 from the fact, that the latent heat as well as the volume of 

 the frozen substance (see plate 21, Yl & Y) increased as the 

 freezing temperature sunk. But as aji explanation it is in- 

 sufficient. It does not hold good in case of sample lY, which 

 is certainly solidified entirelj^ at — 5°.8i C, and also in Y & 

 A^I the discrepanc,y of the latent heat calculated and found is 

 sufficiently great to authorize the conclusion, that: 



III. The latent heat of ice is diminished, if it separates 

 from salt water and in combination with some part of the 

 salt. We could form an idea as to the causes of the low 

 latent heat developed by Yl & Y at — 6° or — 8° C by sup- 

 posing, that the formula of the depression of the latent heat 

 with the freezing temperature given by Clausius and Person 



dr n 



^ = -0.5 .... 



does not hold good for such ice, on account of its spec. heat 

 in the solid and liquid state c and ci being different from 

 that of pure ice. 



Everybody must admit, that the latent heat developed by 

 the freezing of the sea-water has the greatest influence on the 

 conditions of the arctic oceans and on the climate of arctic 

 countries. It will be important then to observe, that the 

 latent heat, which is developed immediately by the solidifica- 

 tion of ocean-water, is very inferior to that of fresh water, 

 but that the freezing process, from a thermic point of view, 

 is not entireJy concluded with the solidification of the sea- 

 water. On further sinking of the temperature, still unfrozen 

 cryohydrates will be solidified and develop heat, until the 

 whole mäss of the ice floe, at sufficiently low temperature, is a 

 solid rock of crystallized matter. At the rise of temperature 



