An Ocean of Azure 



without colour. The petals of a white rose, on 

 the contrary, absorb so little colour of any kind, 

 that practically the entire ray is sent again to 

 us as white light. 



If this is the manner in which the ocean is 

 blue, it means that sea-water, and indeed water 

 generally, must in itself be actually blue, as a 

 cake of ultramarine, a sapphire, a corn-flower, a 

 forget-me-not, are blue. 



Could that be the case ? For a long while 

 men decisively answered No. Everybody knew 

 that water was colourless, so the idea was flung 

 aside as impossible. Another explanation came 

 up instead. 



The sea is full of fine dust ; and it was 

 suggested that, as vast multitudes of these 

 floating dust-particles are exceedingly small, they 

 might be able to reflect only the smaller blue 

 light-waves, and not the larger yellow or the 

 still larger red waves. Thus the sea would 

 naturally seem to be blue. 



After much discussion, careful experiments 

 were made. Different objects were lowered 

 to various depths, and the effect upon their 

 colouring was noted. The outcome of these 

 and other tests went far to prove that the old 



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