474 



A TREATISE ON METAMORPHISM. 



more, it has been seen that oxidation of organic materials by bacteria and 

 oxygen in the belt of weathering produces carbon dioxide abundantly. This 

 process, therefore, concentrates in the upper part of the belt of weathering a 

 laro-e amount of carbon dioxide, and this carbon dioxide is available for the 

 process of carbonation. The fact of the concentration of carbon dioxide in 

 the upper part of the crust of the earth was noted by Bischof many years 

 ago. In the waters of his laboratory well at Bonn he found three times as 

 much carbonate of lime as in the Rhine near by Also, free carbonic acid 

 often collects above the water of wells. Facts like these, and the large 

 amounts of carbonic acids in mines Bischof explained by the oxidation of 

 organic matter, including coal." 



The importance of the process of concentration of carbon dioxide in the 

 belt of weathering through the oxidation of organisms can be appreciated 

 only by comparing the amount of this material in the atmosphere with the 

 amount in the gases of the belt of weathering where vegetation is present. 



The amount of carbon dioxide in rain water, according to Fischer, 

 a aries from 0.22 to 0.45 per cent of the volume of the water, or only 0.00044 

 and 0.00089 per cent by weight.'' 



It has already been noted that the amount of the carbon dioxide in the 

 atmosphere by weight is about 4.5 in 10,000. The amount present in 

 gases of the soil is far greater than this, as shown by the following table 

 by Boussingault and Lewy : c 



Table shoiuing the amount of carbon dioxide in the air of belt of weathering . 



"Bischof, Gustav, Elements of chemical and physical geology, Harrison & Sons, London, 1854, 

 vol. 1, p. 239. (Translated by Paul and Drummond. ) 



6 Merrill, George P., Rocks, rock-weathering, and soils, Macmillan Co., New York, 1897, p. 179. 

 '■Merrill, cit,, p. 178. 



