THE SALTS OF THE SEA. 291 



lias been computed, cover tlie ground one mile deep. What force 

 could move such a mass of matter on the dry land? Yet the 

 machinery of the ocean, of which it forms a part, is so wisely, 

 marvelously, and wonderfully compensated, that the most gentle 

 breeze that plays on its bosom, the tiniest insect that secrets solid 

 matter for its sea-shell, is capable of putting it instantly in mo- 

 tion. Still, when solidified and placed in a heap, all the mechan- 

 ical contrivances of man, aided by the tremendous forces of all 

 the steam and water power of the world, could not move even so 

 much as an inch in centuries of time this matter which tlie sun- 

 beam, the zephyr and the infusorial insect keep in perpetual mo- 

 tion and activity. 



528. If these inferences as to the influence of the salts upon 

 the currents of the sea be correct, the same cause which produces 

 an under current from the ]\Iediterranean, and an under current 

 from the E-ed Sea into the ocean, should produce an under cur- 

 rent from the ocean into the north Polar basin. In each case, the 

 hypothesis with regard to the part performed by the salt, in giv- 

 ing vigor to the system of oceanic circulation, requires that, coun- 

 ter to the surface current of water with less salt, there should be 

 an under current ot water with more salt in it. 



529. That such is the case with regard both to the Mediterra- 

 nean and the Eed Sea has been amply shown in other parts of this 

 work (§ 523), and abundantly proved by other observers. 



530. That there is a constant current setting out of the Arctic 

 Ocean through Davis's and other straits thereabout, which con- 

 nect it with the Atlantic Ocean, is generally admitted. Lieuten- 

 ant De Haven, United States Navy, when in command of the 

 American expedition in search of Sir John Franklin, was frozen 

 up with his vessels in mid-channel near Wellington Straits ; and 

 during the nine months that he was so frozen, his vessels, like 

 H. B. Si. ship Eesolute (§ 487), each holding its place in the ice, 

 were drifted with it bodily for more than a thousand miles toward 

 the south. 



531. The ice in which they were bound was of sea water, and 

 the currents by which they were drifted were of sea water — only, 

 it may be supposed, the latter were not quite so salt as the sea 



