THE GENESIS OF THE DIAMOND 631 



very generally received, that atmospheric weathering has trans- 

 formed the "hard blue" ground into "soft blue," and this in turn 

 into "yellow" ground. If, as here suggested, there had been a 

 previous period in which serpentine and calcite were formed, 

 evidence for or against it should be found in the transition zone 

 between the hard and the soft blue ground. So far as can be 

 gathered from the literature at hand careful search has never been 

 made for such evidence. This seems thus to be one of the crucial 

 points in the study of the genesis of the diamond that is yet to be 

 investigated. 



On the assumption that future investigation may establish the 

 deep-seated origin of the alteration of the diamond matrix, a basis 

 is found for submitting to discussion the elements of a new hypothe- 

 sis regarding the genesis of the diamond. A pipe filled with rock 

 fragments saturated with hot (possibly superheated) gases, and 

 probably also liquids, would constitute an enormous crucible, in 

 which reactions not as yet detected in our laboratories might take 

 place. In this crucible carbon would certainly be present in the 

 form of carbonic acid and probably in other gaseous forms as well. 

 Thus the material and some of the physical conditions for unusual 

 carbon segregation were present, and we are not yet, apparently, 

 in a position to say that a segregation of a minute portion of the 

 carbon into a solid form is a chemical impossibility. It seems to be 

 well established that in certain industrial and experimental processes 

 carbon does separate in the solid form of graphite from carbonaceous 

 gases, and Weinschenk has presented strong evidence in favor of 

 the introduction in a gaseous form of the carbon of the graphite 

 deposits of Bohemia and Bavaria. 



From a geological point of view the role of carbon in eruptive 

 rocks and in eruptive phenomena generally is as important as it 

 is obscure. It thus presents an attractive subject for experimental 

 researches, such as are contemplated in the program of the Geophysi- 

 cal Laboratory at Washington, which is so admirably equipped both 

 in material and personnel for such investigations. The inquiries 

 in this line thus far reported by various experimenters, while 

 extremely interesting and important in themselves, are unsatis- 

 factory, in so far as they postulate conditions that are with diffi- 

 culty conceivable in nature. 



