14 
THE OCEAN WORLD. 
very deep ; when the sand is yellow, the green appears more sombre ; 
the presence of rocks is often announced by the deep colour which the 
sea takes in their vicinity. In the Bay of Loango the waters appear 
of a deep rod, because the bottom is there naturally red. It appears 
white in the Gulf of Guinea, yellow on the coast of Japan, green to the 
west of the Canaries, and black round the Maidive group of islands. 
The Mediterranean, towards the Archipelago, sometimes becomes more 
or less red. The White and Black Seas appear to be named after the 
ice of the one and the tempests to which the other is subject. 
At other times, coloured animalcules give to the water a particular 
tint. The Bed Sea owes its colour to a delicate microscopic algae 
( Trychodesmium erythrmum), which was subjected to the microscope 
by Ehrenberg ; but other causes of colouration are suggested. Some 
microscopists maintain that it is imparted by the shells and other 
remains of infusoria; others ascribe the colour to the evaporation 
which goes on unceasingly in that riverless district, producing salt 
rocks on a great scale all round its shores. In the same manner 
sea water, concentrated by the action of the solar rays in the salt 
marshes of the south of France, when they arrive at a certain stage of 
concentration take a fine red colour, which is duo to the presence of 
some red-shelled animalcules which only appear in sea water of this 
strength. Strangely enough, these minute creatures die when the 
waters attain greater density by further concentration, and also if it 
becomes weaker from the effects of rain. 
Navigators often traverse long patches of green, red, white, or yellow 
coloured water, all of which are due to the presence of microscopic 
crustaceans, medusae, zoophytes, and marine plants ; the Vermilion Sea 
on the Californian coasts is entirely due to the latter cause. 
The phenomena known as Phosphorescence of the Sea, is due to > 
analogous causes. This wonderful sight is observable in all seas, hut 
is most frequent in the Indian Ocean, the Arabian Gulf, and other 
tropical seas. In the Indian Ocean, Captain Kingman, of the American 
ship Shooting Star, traversed a zone twenty-three miles in length so 
filled with phosphorescent animalcules that at seven hours forty-five 
minutes the water was rapidly assuming a white, milky appearance, 
and during the night it presented the appearance of a vast field of 
