DIATOMS AND WHALES 265 



the discharge of artillery ; and with a great regurgitation 

 of the waves the iceberg is launched into life. These 

 huge floating islands of ice are the most conspicuous 

 exports of Greenland ; and their true magnitude is not 

 realised until it is remembered that only about an 

 eighth of their bulk appears above the water. Bergs as 

 large as liners we frequently hear of one such is shown 

 in our illustration but sometimes they are of much 

 greater freeboard, though the very large ones reported 

 as extending along the horizon are invariably groups of 

 several crowded together. 



Ancylonema has evidently plenty to do. Another 

 instance of the important part played by the insignificant 

 in these regions is suggested by the colour of the sea. 

 This varies from ultramarine blue to olive-green, from 

 the purest transparency to striking opacity ; and the 

 changes are not transitory but permanent. These 

 patches of dark water abound with diatoms, while the 

 bluer the water the fewer are the diatoms ; and where 

 they are most numerous, there the animals that feed on 

 them assemble in their greatest numbers. And these 

 animals are jellyfish, entomostracans, and, to a greater 

 extent, pteropods, their chief representative being Clio 

 horcalis. In short, the animals that feed on the diatoms 

 are food of the Greenland whale, and where the waters 

 are dark the whale-fishers thrive. " I know nothing 

 stranger than the curious tale I have unfolded," says 

 Dr. Robert Brown, who worked out this remarkable 

 chain, " the diatom staining the broad frozen sea, again 

 supporting myriads of living beings which crowd there 

 to feed on it, and these again supporting the huge 

 whale. Thus it is no stretch of the imagination to say 



