Chemistry and Physics. 387 



waters nowhere contain more than 15*6 c.c. of nitrogen or more 

 than 8*18 c.c. of oxygen per liter; and that the nitrogen never 

 falls below 8*55 c.c. The oxygen is diminished below its theoret- 

 ical minimum 4"30 c.c. by the processes of life and organic decom- 

 position and other oxidation changes. In waters at depths the 

 variation in amount of oxygen is greater, because of the feeble 

 source of supply and the losses from oxidation. No deep-sea 

 water was found, in the analyses, wholly without free oxygen^ 

 and this "confirms the conviction that absolute stagnation no- 

 where exists in the ocean, not even at its greatest depths." But 

 in one sample the amount of cubic centimeters per liter was found 

 to be 15-08 N 2 and 6 O ; in another 13-38 N 2 and 2-04 O ; " indi- 

 cating approximate rest at these two places at any rate." At the 

 ocean's surface the equilibrium in the absoi'bed nitrogen and 

 oxygen is maintained by the atmosphere. 



As to carbonic acid in sea-ioater, all the waters were found to 

 contain it, and those from the deep sea were particularly rich in 

 it. The analyses prove that " if sea-water anywhere contains free 

 C0 2 at all, it amounts to little in comparison even with the com- 

 bined C0 2 of the carbonates." But sea-water may give off C0 2 

 even when only enough is present to make all the lime bicarbonate. 

 Experiments showed that the loss may continue until there re- 

 mains only what is necessary to make the lime a sesquicarbonate. 

 "In surface waters the proportion of carbonic acid increases when 

 the temperature falls, and vice versa;" and "within equal ranges 

 of temperature it seems to be lower in the surface water of the 

 Pacific than it is in that of the Atlantic Ocean." Free carbonic 

 acid is, however, occasionally in rather large proportion, 22 out 

 of 195 waters analyzed by Mr. Buchanan having their surplus 

 base at least fully saturated, and one, although a surface water 

 at 25*1° C, contained as much as 41 milligrams of free CO„ per 

 liter." 



The total weight of potential carbonate of lime in the ocean 

 amounts to 160 billion tons, equal to 70 such units of C0 2 ; but as 

 the C0 2 is present as partially saturated bicarbonate, 105 billion 

 tons may be accepted as a rough approximation. The source of 

 this C0 2 Mr. Dittmar supposes to be from submarine volcanic 

 action. As volcanoes get the C0 2 by decomposing limestone 

 about the conduit, it would in that case come from the calcareous 

 material of the ocean's depths, or from the earth's crust beneath, 

 set free by volcanic heat. 



The total weight of loose C0 2 in the ocean is at least 15 times 

 greater than that of the free C0 2 in the air. If the amount of 

 lime carbonate contributed by all the rivers of the world is as- 

 sumed to equal the total solids which the thirteen rivers before 

 named contribute, 1*3375 XlO 9 tons, it would take them 1194 

 years to increase the amount in the ocean one per cent of its pres- 

 ent value, the sum total of the carbonate of lime of the. ocean 

 being 160 billion of tons. 



