of sea waters, in different parts of the ocean, &c. 1 83 
remained stationary at that point. The ice being taken out of 
the receiver and the vessel inverted, a small quantity of 
strong brine drained off from it. This was mixed with the 
portion of water, which, in the former experiment, had es- 
caped congelation, and the specific gravity of these mixed 
unfrozen residues proved to be 1035,16; whilst that of the 
frozen portions, after being washed with distilled water, then 
melted and mixed together, was 1015,2. These results seem 
to show that a certain degree of rest and slowness in the 
process, and probably also a certain mass of water, are con- 
ditions required for the entire separation of the salt ; and 
hence we are enabled to account for the slight differences 
which we observe in this respect, in various specimens of 
water taken from the frozen surface of the sea.* 
With regard to the important questions connected with the 
temperature of the Arctic seas, it will be seen by a reference 
to the tables, that this interesting subject of inquiry was not 
overlooked in the late Northern Expeditions, and that some 
curious observations were made in those regions, on the tem- 
perature of the sea, both at the surface and at different depths. 
Thus for instance it is stated in the 1st. Article of Table I., on 
the authority of Captain Ross, that in lat. 66,50, and long. 
68,30, west, the temperature of the air being 36°, that of the 
* 1 have also frequently, in the course of these experiments, frozen, by means of 
cooling mixtures, small quantities of sea water in tubes, with a thermometer in the 
water. When a certain degree of agitation was used, the water generally froze at 
about 25 0 or 26°; but when, (as will be seen in the latter part of this paper,) a more 
considerable vessel of sea water was exposed to congelation, the vessel being quite 
full and kept at rest, the water was cooled to between 18 0 and 19 0 before it became 
solid. In either case the thermometer uniformly rose to 28®, at the moment of 
congelation. 
