MARINE PLANTS. 19 



If I were to attempt to describe this pheno- 

 menon, I would say that the surface of the ocean 

 was entirely covered with a thin, close layer of 

 fine matter, the colour of brick-dust, but 

 slightly orange. Mahogany saw-dust would 

 produce such an appearance. When put into 

 a white glass bottle, it became in the course of 

 a day deep violet, while the water itself had 

 become a beautiful rose-colour. This appear- 

 ance lasted for about a day and a half, after 

 which the sea became blue as before. During 

 this time we must have passed through about 

 two hundred and fifty- six miles of the red 

 plant." Off Bahia, on the coast of Brazil, 

 bands, several miles long, occur, of a species 

 like chopped hay. But some of the minute 

 sea-weeds are the most marvellous. In the 

 Antarctic Ocean vast multitudes of one of the 

 Diatomacece occur, so minute as to be invisible 

 to the naked eye, and yet swarming in such 

 countless myriads as to give the sea a pale 

 ochreous brown colour. 



The thought of such numbers confounds the 

 mind. On their first discovery they were 

 thought to be animalcules of the silicious 

 shelled kind, but they are now ascertained to 

 be vegetables. They augment in quantity as 

 the latitude increases, up to the highest point 

 attained by man ; and from the 1 65th to the 160th 

 degree of west longitude, between the 76th and 

 78th parallels of south latitude, the hard remains 

 of this vegetable are forming a submarine bank, 

 from two to three hundred miles long, and of great 



