506 



THE AMERICAN MUSEUM JOURNAL 



"Michael Sars" upon currents, that the 

 ocean is more elastic, so to speak, than 

 we had supposed. Thus it breaks up 

 into "regions of vibration" in its tidal 

 movements. For example, the Medi- 

 terranean is cut into two distinct tidal 

 areas by the narrow channel, blocked 

 by Sicily, between Italy and Africa, and 

 we now know that over the ocean there 

 are many more or less independent tidal 

 regions bounded by chains of islands or 

 embayed by continental shores, and 

 tidal waves may affect not only the 

 surface but be detected a thousand feet 

 or more beneath. Thus a surface cur- 

 rent flowing northward must be counter- 

 balanced by a deep one flowing south- 

 ward, and this is why the cold Arctic 

 waters wander toward the tropics along 

 the deep-lying ocean floor, the tempera- 

 ture at eighteen thousand feet under the 

 equator being only slightly above the 

 freezing point. 



Thus it is that the floors of the deep 

 open oceans are covered with cold polar 

 water and the deep sea animals off 

 Nantucket are strikingly like those off 

 Ceylon, while similarly, the surface 

 creatures of the West Indies bear a close 

 general resemblance to those of the 

 tropical Pacific. Indeed, so important 

 a factor is temperature in the control of 

 animal life that probably not one in a 

 thousand of the West Indian species 

 ranges north of Cape Cod. 



Thus the West Indian creatures which 

 appear along our shores in summer are 

 children of the surface drift whose lives 

 lie at the mercy of the current and the 

 wind as they ceaselessly float eastward 

 across the tropical Atlantic and then 

 through the wide sweep of the great 

 ocean eddy to be returned to the shores 

 of Africa, thence outward from the 

 peril of the beaches to the free and open 

 sea. 



Photo by A. G. Mayer 

 No forests are more somber than stately live oaks, heavy with their burden of " tree moss." Yet curi- 

 ously this plant is not a moss, but is a relative of the pineapple. It flourishes in the damp warm air of our 

 southern coast from Florida to South Carolina, and will grow upon telegraph wires quite as readily as upon 

 live oaks 



