310 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JunC 1, 



Cape York may arise from some local cause, such as the presence of 

 an unusually large number of icebergs. On our own coasts the mean 

 density of the sea is often disturbed by the discharges of rivers and 

 small streams. An evening of rainy weather in November of the past 

 year reduced the density of the sea in Stromness harbour from 1 "0285 

 to 1'0235, and eighteen hours of heavy rain on the l/th of the same 

 month reduced that of the water of St. Margaret's Hope, Frith of 

 Forth, from 1*0245 to r0185. Before, however, this theory of a 

 northerly seeking current in Davis' Straits along the eastern shore 

 can be accepted, we must get over the difficulty arising from the 

 position of the great Arctic current in the North Atlantic. This 

 current sweeps southward across the entrance of Davis' Straits and 

 prevents the ingress at the surface of any water from the Atlantic, 

 except such as the current itself would supply. The Rev. Dr. 

 Scoresby suggests the idea that two currents may arise from the ex- 

 istence of two strata of water varying in temperature*. The question 

 then arises as to the order of superposition. If sea- water indepen- 

 dent of its saline ingredients follows the law of expansion peculiar to 

 water from 40° to 32°, one current at a temperature of 36° may jjass 

 over another at 44°, and if we separate the extremes eight degrees more, 

 the coldest is still the most buoyant, for, even although it is sea-water, 

 if in a state of tolerable quiescence a portion of it will have become 

 congealed. It is a well-known fact that the process of congelation 

 separates the saline from the watery particles. I have often observed 

 sea- water freezing when the immersed thermometer stood at 32°, and 

 the ice produced at the time was found to contain little more than a 

 trace of saline matter. But there seems to be no reason why this 

 separation should be confined solely to the act of congelation, since 

 it is owing to the universal law of contraction observed in obedience 

 to cold by, I believe, everything in nature except water itself, and 

 that only between the temperatures of 40° and 32°. This may ap- 

 pear somewhat at variance with the experiments of Erman, as quoted 

 by Sir Charles Lyellf ; the latter, however, acknowledges the pos- 

 sibility of the colder and more diluted water of the Arctic current 

 passing over the warmer and more sahne waters of the Gulf Stream. 

 Until our knowledge of the physical changes peculiar to these high 

 latitudes extends, such phsenomena as the above must remain more 

 or less obscure ; at present we may rest assured that a meeting and 

 commingling of waters differing in point of saltness and temperature 

 takes place in the entrance of Davis' Straits, and to this causing 

 sudden and decided meteorological changes may be attributed, in 

 great measure, the extreme violence of the storms experienced by 

 navigators when they approach Cape Farewell. 



Sea-bottoms and Soundings. — Presuming then upon the existence 

 of currents into the Arctic Seas which may assist the action of the 

 sun in dissolving icebergs and sea-water-ice, we are in a position to 

 consider the extent and character of deposits and accumulations of 

 drift material or " till " now forming in the track of these conveying 



* Sir Charles Lyell's Principles of Geology, 7th edit, page 97. f ■^*«^- 



