Physical Geography of the Great Oceans 109 



not supplied by a long surface current, but by a short vertical 

 one. This view is very strongly supported not only by the 

 temperature of the water, but by its other character!- 

 especially colour. The outside ocean water is of an intense 

 ultramarine blue; the coast water off Mogador had the clear 

 olive-green colour met with constantly in Antarctic seas. 

 The same is observed on the west coast of North and South 

 America, and it would be of the highest interest to have these 

 waters investigated from a biological point of view. No 

 waters in the ocean so teem with life as those on the west 

 coast of South America. A bucket of water collected over the 

 side is turbid with living organisms, the food of countless 

 shoals of fish, who, in their turn, afford prey for innumerable 

 schools of porpoises. One remarkable school which accom- 

 panied the ship for some time consisted entirely of females, 

 each accompanied by a calf following in her wake and mimicking 

 her every movement. Along with abundance of life this coast 

 unites facilities for investigating it. At every port there are 

 !>! nty of shore boats anxious for a fare, and with a tow net 

 and a few bottles a naturalist might make a rich collection of 

 the shore-water fauna of the coast in one trip from Valparaiso 

 to Panama. 



The characteristics of inshore water of the \\irn! 

 coasts of the oceans are, an abnormally low temperature, 

 IK a comparatively low density, and always a pronounced 

 peculiar green colour. These characteristics are found 

 ked in the water between the shore and the loo fathom 

 ater, as it drifts out to sea, rapidly !<>-<> its low 

 ure, and its green colour is bleached. In the year 

 1883 whm, through the kindness of the Sil\it'\\n ( .'inj 

 ! the opportunity of raiTving out some research s in i 

 "Dacia, I ' a number of six IK irnm the D 



Bank, Ivin^ brtw-n T< .md M.nl. ira. These shells 



were all M..in<d with a green colour, which came out 

 colon ! in whi.-li thrv \vn. 



thi< rolnuivd -j.int tc in I'rofessoi Dublin. 



olouring matter to be s of 



"l>h\ll. Some of the colour. of the " u;er" 



