THE DRIFT OF THE SEA. 3^5 



nials tliat inhabit the mighty deep, time will only tell ; I can not 

 think it will." 



906. These discolorations are no doubt caused by organisms 

 of the sea, but whether wholly animal or wholly vegetable, or 

 whether sometimes the one and sometimes the other, has not been 

 satisfactorily ascertained. I have had specimens of the coloring 

 matter sent to me from the pink-stained patches of the sea. They 

 were animalcula3 well defined. The tints which have given to the 

 Red Sea its name may, perhaps, be in some measure due to agen- 

 cies similar to those which, in the salt-makers' ponds, give a red- 

 dish cast (§ 3) to the brine just before it reaches that point of con- 

 centration when crystallization is to commence. Some micro- 

 scopists maintain that this tinge is imparted by the shells and 

 other remains of infusoria which have perished in the growing 

 saltness of the water. The Red Sea may be regarded, in a cer- 

 tain light, as the scene of natural salt-works on a grand scale. 

 The process is by solar evaporation. No rains interfere, for that 

 sea (§ 404) is in a riverless district, and the evaporation goes on 

 unceasingly, day and night, the year round. The shores are 

 lined with incrustations of salt, and the same causes which tino-e 



o 



with red (§ 3) the brine in the vats of the salt-makers, probably 

 impart a like hue to the arms and ponds along the shore of this 

 sea. Quantities, also, of slimy, red coloring matter are, at certain 

 seasons of the year, washed up along the shores of the Red Sea, 

 which Dr. Ehrenberg, after an examination under the microscope, 

 pronounces to be a very delicate kind of sea-weed : from this mat- 

 ter that sea derives its nam^e. So also the Yellow Sea. Along 

 the coasts of China, yellowish-colored spots are said not to be un- 

 common. I know of no examination of this coloring matter, how- 

 ever. In the Pacific Ocean I have often observed tliese discolor- 

 ations of the sea. Red patches of water are most frequently met 

 with, but I have also observed white or milky appearances, which 

 at night I have known greatly to alarm navigators by their being 

 taken for shoals. 



907. These teeming waters bear off through their several chan- 

 nels the surplus heat of the tropics, and disperse it among the 

 icebergs of the Antarctic. See the immense equatorial flow to the 



