222 THE POPULAR SCIENCE MONTHLY. 



hardly take any fish, at least in the daytime, if they could see as 

 far as we see in the air. 



The color of water varies from "blue to greenish, usually ac- 

 cording to the degree of its clearness. Objects at twenty metres' 

 depth begin to take a bluish hue, and at from twenty-five to thirty 

 metres the light is so blue that dark-red animals look black, while 

 green and bluish sea-weeds seem almost white by contrast. Com- 

 ing back quickly into the air, eyes accustomed to the blue light 

 see the air-landscape red. The red rays are extinguished first, a 

 fact which had been already demonstrated by laboratory experi- 

 ments. The blue rays, being absorbed in a less degree, penetrate 

 farther ; and these are the rays which act most energetically on 

 the photographic plate. This fact disposes of the objections 

 which some students have repeated with a persistency that is 

 not creditable to their ideas of physics, against the use of photo- 

 graphic plates in determining the depth to which daylight can 

 penetrate through water. 



When there is a swell, the diver's task is a hard one. He is 

 constantly tossed about in spite of himself, and an irresistible 

 force compels him to swing like a pendulum. This oscillation of 

 the water, which is a counterpart of the waves of the surface, is 

 nearly as perceptible at thirty metres as at ten metres. It can 

 not be a surf phenomenon, for fishermen find that, after a storm, 

 depths of fifty metres and more are swept by it. S]3ecial appa- 

 ratus and experiments are required to determine to what depth it 

 extends ; but, in view of the incompressibility of water, I should 

 not be astonished to find it extending very far down. In this 

 matter, as well as in a great many others, the diver is in a con- 

 dition to gain valuable information by which new avenues may 

 be opened for the study of the phenomena of Nature. Translated 

 for The Popular Science Monthly from the Revue Scientifique. 







DRESS AND PHYSIQUE OF THE POINT-BARROW 



ESKIMOS. 



By JOHN MUEDOCH. 



THE people who live on the extreme northwest corner of our 

 continent are far from being an ugly or an ill-made race. 

 Though they are not tall a man of five feet ten inches is a tall 

 man among them they are well-proportioned, broad-shouldered, 

 and deep-chested. The men, as a rule, are particularly well " set 

 up," like well-drilled soldiers, and walk and stand with a great 

 deal of grace and dignity. I fancy that a good deal of the erect 

 carriage of the men comes from their habit of carrying the gun, 



