i9o6] OF DEEP-SEA CIRCULATION. 37 



recognized. Certain less familiar ones have been brought under 

 study in recent years by a few students independently. Schloesing 

 was perhaps the first to clearly recognize that the carbon dioxide of 

 the ocean is an important agency in the regulation of the atmos- 

 pheric content of this critical factor. As early as 1880^ he advanced 

 the view that the carbon dioxide of the atmosphere is in equilibrium 

 not only with the free carbon dioxide absorbed in the sea water but 

 through dissociation with the second equivalent of carbon dioxide in 

 the oceanic bicarbonates. The sum-total of such free and loosely 

 combined carbon dioxide available at present as a possible supply for 

 the atmosphere may be some twenty-five times the present atmos- 

 pheric content. Schloesing held that any depletion of the atmos- 

 pheric content would be followed by emanation from the ocean, and 

 any excess acquired by the atmosphere would be followed by oceanic 

 absorption, and hence great changes in the atmospheric content 

 would only be brought about by reducing or increasing the large 

 sum-total of atmospheric and oceanic supply. This was a contribu- 

 tion of the first order to the problem of atmospheric regulation. It 

 is necessary for a geologist, however, to recognize that the exchange, 

 and even the equilibrium itself, are dependent on geological and 

 physical conditions. At periods in which the oceanic bicarbonates 

 were most abundant, the amount of free and loose carbon-dioxide 

 in the ocean may perhaps have reached thirty or forty times the 

 present atmospheric content, while on the other hand it may have 

 fallen to a very low figure when the ocean was depleted of carbo- 

 nates. It is necessary also to recognize that the diffusion of gases 

 in water, so far as it is covered by experiment, is a slow process, and 

 computation seems to show that the supply of carbon dioxide to the 

 atmosphere might be much too slow to offset its consumption under 

 certain geologic conditions, unless effectively aided by oceanic cir- 

 culation. The active superficial circulation immediately assignable 

 to the winds would aid somewhat but its competency is limited. It 

 was in an attempt to determine the functions of the deep-sea circula- 

 tion in this interchange that the conceptions of this paper arose. 



^ " Sur la Constance de la proportion d'acide carbonique dans I'air," Comp. 

 Rend., 1880, t. 90, p. 1410. 



