143 Royal Society. 



the necessity for currents from the two poles of the earth, where de- 

 position of vapour predominates to a considerable extent over eva- 

 poration. This he illustrates by referring to the constant current 

 from the Atlantic into the Mediterranean, caused by the evaporation 

 in this sea preponderating over the supply of fresh-water. He 

 then points out the necessity also of a current out of this sea, in 

 order that its waters, by the constant influx of saline matters, may 

 not become a saturated solution of the salts of the ocean ; and 

 infers that counter- currents into the polar seas must also exist to 

 obviate the contrary tendency which the waters of these seas have 

 to become fresh. He calls attention to the importance of ascer- 

 taining the differences that occur in many parts of the surface of 

 the ocean in respect to its saline contents, that we may be enabled 

 to determine to what extent the currents and counter- currents may 

 be influenced by the comparative freshness of the iced water of the 

 northern and southern regions, and the necessary saltness of the 

 equatorial and other overheated basins. On this point, with re- 

 spect to the Arctic seas, he refers to observations by Dr. Scoresby, 

 Sir Edward Parry, and those recorded in tables appended to this 

 paper, which have been extracted from the Meteorological Journal 

 kept in the North Atlantic and Davis's Straits during the late voyage 

 in the Isabel. 



The author next refers to the remarkable difference occurring in 

 the climate of the east and west sides of Davis's Straits, that of the 

 latter being much the colder. In the absence of thermometric re- 

 gisters for the west, to compare with those on the east side, he points 

 out how the appearance of the land and development of plants and 

 land animals on the two coasts enable us to determine which has 

 the warmer climate. Looking from the top of Baffin's Bay, which 

 commands a good view of both shores, the east side at the sea-coast 

 has many portions of land free from snow, whereas the opposite, by 

 its snowy and icy covering, presents an appearance altogether un- 

 congenial. On the former are found a tolerably abundant flora, 

 hares and deer ; on the latter, there scarcely appears to be a spot to 

 receive the roots of plants or the feet of these animals ; and in the 

 productions of the sea, both vegetable and animal, the same dispro- 

 portion is met with. Upon the whole, he considers complete the 

 analogy that exists between the North Atlantic and Davis's Straits, 

 both with respect to the climate of their shores and to their inhabit- 

 ants of the animal and vegetable kingdoms. With reference to 

 the question how this analogy is brought about, the author considers 

 it difficult to decide whether the increase in the temperature of the 

 water and the consequent improvement of the climate, on the east 

 side of the strait, arise from the disposition the ice has to leave the 

 coast, by which means the water becomes exposed to the influence 

 of the sun ; or from currents of heated water from a more southern 

 region. He further remarks that its density here cannot be restored, 

 if once disturbed, without admixture with a large volume of water 

 somewhat above the mean density. 



Again referring to the observations of Sir Edward Parry and those 

 recorded in the tables, the author remarks that from these it will be 



