THE BASIN AND BED OP THE ATLANTIC. 323 



how strong, how light yet how firm are the foundations of the 

 sea ! Its waves cannot fret them, its currents cannot wear them, 

 for the bed of the deep sea is protected from abrasion by a 

 cushion of still and heavy water. There it lies — that beautiful 

 arrangement — spread out over the bottom of the deep, and 

 covering its foundations as with a garment, so that they may not 

 bo worn. If the currents chafe upon it now here, now there, as 

 in shallow seas they sometimes do, this protecting cushion is 

 self-adjusting ; and the moment the unwonted pressure is removed 

 the liquid cushion is restored, and there is again compensation. 



600. Tlie causes that produce currents in the sea reside near its 

 surface. — The discovery of this arrangement in the oceanic 

 machineiy suggests that the streams of running water in the sea 

 play rather about its surface than in its depths ; that the causes 

 which produce currents reside at and near the surface ; that 

 these causes are changing heat and alternating cold with their 

 powers of contraction and expansion — winds and sea-shells with 

 evaporation and precipitation; and it is certain that none of 

 these agents appear capable of reaching with their influences 

 very far down into the depths of the great and wide sea. They 

 go not much, if any, farther down than the light can reach. On 

 the other hand, the most powerful agents in the atmosphere 

 reside at and near its bottom; so that, where these two gi'eat 

 oceans meet — the aqueous and the aerial — there we probably 

 have the greatest conflict and the most powerful display of the 

 forces that set and keep them in motion, making them to rage 

 and roar. 



601. Tlieir depth. — The greatest depth at which running water 

 is to be found in the sea is probably in the narrowest part of the 

 Gulf Stream, as, coming from its mighty fountain, it issues 

 through the Florida Pass. The deep-sea thermometer shows 

 that even here there is a layer of cold water in the depths 

 beneath, so that this " river in the sea" may chafe not against 

 the solid bottom. What revelations of the telescope, what 

 wonders of the microscope, what fact relating to the physical 

 economy of this terrestrial globe, is more beautiful or suggestive 

 than some of the secrets which have been fished up from the 

 caverns of the deep, and brought to light from the hidden paths 

 of the sea ? 



602. The cushion of still water — its tJiichicss. — In my researches 

 I have as yet found no marks of running water impressed upon 



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