142 AIR AND LIFE. 



of carbonic acid in ground, air fully explains a number of accidents, 

 inasmuch as while the proportion of this gas is considerably increased 

 that of oxygen is greatly diminished. 



Air penetrates to a great depth in water, whether fresh or salt. This 

 is shown by the number of living forms found, not only at the surface 

 or in its neighborhood, but at the greatest depths to which man has 

 yet been able to lower his nets, dredges, and sounding apparatus. 

 Since living organisms exist in the depths of the ocean, and since 

 they are physiologically, in their most important features, constructed 

 on the same principles as those which live near the surface, it is obvi- 

 ous that in the waters of the deep, air must be dissolved of which they 

 take advantage for their respiratory functions. Direct and precise 

 observation fully confirms this inductive reasoning. Many instruments 

 have been devised for the purpose of obtaining water from different 

 depths. One of the first was the bottle, which was used by the Kiel 

 committee. This bottle, firmly stopped and empty, was lowered to the 

 required depth, and a sudden pull was enough to cause it to open, the 

 surrounding water filling it in a few seconds. Many similar imple- 

 ments have been since invented by Bun>en, Meyer, Mill, Buchanan 

 (Challenger), Ellman, Sigsbee (Blake), Bichard, Yillegente, and Paul 

 Begnard. The description of these instruments is given at length in 

 man y works — for instance, in T. Thoulet's Oceanographie (Vol. I), Paris, 

 1890, and P. Begnard's La vie dans les eaux, Paris, 1891 — where the 

 reader who desires full information on the matter may find it, and it 

 will saffice for our purpose to give a general summary of the results 

 obtained, without detailing the methods by which water is brought to 

 the surface from different depths, or those, familiar to all, by which 

 the gases contained in water are extracted and submitted to chemical 

 analysis. In short, the results of these experiments fully and com- 

 pletely confirm the opinion above expressed, that even at the greatest 

 depths water does contain air; that the atmosphere extends down to 

 the nearly unfathomable abysses of the ocean. 



As to rivers and lakes, or other shallow waters, the demonstration is 

 most easy. Their water contains oxygen, nitrogen, and carbonic acid. 

 But it is a noteworthy fact that these gases are not to be found in the 

 proportions in which they exist in the atmosphere. Strictly speaking, 

 one can not say that there is any air in water. What we find are the 

 elements of air, the latter being all present, but their proportions 

 being different from those in the normal atmosphere. For instance, 1 

 liter of river water contains from 4 to 8 cubic centimeters of oxygen; 

 from 12 to 18 cubic centimeters of nitrogen, and from 2 to 20 or 25 cubic 

 centimeters of carbonic acid. These proportions differ greatly from 

 those which these three constituents have in normal air, and it must be 

 noted that the variations are different in different rivers or even in 

 the same river when examined in different places. Take the Seine 

 Biver, for instance. Each liter of water contains 32.1 cubic centimeters 



