REDISTRIBUTION OF CARBON. 973 



coal, in 812 years the amount of carbon dioxide added by this process 

 would be equal to the total carbon dioxide of the atmosphere. 



Possibly carbon dioxide may be steadily gathered to the earth from the 

 interplanetary or interstellar spaces by the force of gravity. According 

 to Hunt, this idea was first suggested by Sir William Grove in 1843/' 

 This source of carbon dioxide Hunt regards as the chief one. The pos- 

 sibility of segregation of carbon dioxide from the stellar spaces has been 

 recently brought forward again by Chamberlin. 6 



If we write an equation representing the amount of carbon dioxide in 

 the sedimentary rocks we have the following: 



(2.64+ .81 X 44/ 12) X .65 + (3.03 X .30) + (38.58 X .05) = 6.4585. 



In the above equation 2.64 is the C0 3 in shales and 0.81 is the carbon 

 contained as carbonaceous material in shales, which must be multiplied by 

 44/12 in order to find the equivalent amount of C0 2 . The above equation 

 does not take into account coal and other especially carbonaceous deposits, 

 which would increase the quantity. Even omitting the coal deposits, the 

 average amount of carbon in the sedimentary rocks is 8 times greater than 

 Clarke's estimate of the amount of carbon dioxide in the original igneous 

 rocks, 0.81 per cent. As in the case of sulphur, it is not necessary to 

 suppose that these two amounts should balance, for there may have been 

 originally a large amount of carbon dioxide in the atmosphere and hydro- 

 sphere not derived from the crystallized rocks. Also, as has been pointed 

 out, it is little short of certain that the carbon originally in magma, either as 

 carbon, hydrocarbons, or carbon dioxide, largely escapes as carbon dioxide 

 at the time of the crystallization of the rocks. At this time of escape the 

 hydrocarbons and carbon are largely oxidized to C0 2 . However, the 

 above equation shows it to be certain that the original crystallized igneous 

 rocks do not constitute the sole, or even the chief, source of the carbon 

 which has taken such an important part in the economy of the earth. 



In summary it appears that the carbon of the lithosphere was' originally 

 widely dispersed in small quantities. The operations of metamorphism 

 concentrate carbon in the carbonates and carbonaceous deposits, and to a 



"Hunt, T. Stsrry, The geological relations of the atmosphere: Rept. Brit. Assn. Adv. Sci., 1878, 

 p. 544. 



6 Chamberlin, T. 0., A group of hypotheses bearing on climatic changes: Jour. Geol., vol. 5, 

 1897, pp. 653-683. 



