6U 



users of coal from large storage heaps, it may not be without 

 value as an indication of weathering effects in actual practice. 



Further studies are to be continued, having reference to actual 

 storage conditions. 



II. Deterioratton of Coal. 



Summar}^ of results : 



(a) An exudation of combustible gases from coal occurs from 

 the time of breaking out of the sample from the vein. 



(b) An absorption of oxygen accompanies the exudation of 

 hydrocarbons. 



(c) Samples of coal in most carefully sealed containers are 

 subject to deterioration. 



(d) The process of deterioration is probably due to oxidation 

 of hydrogen or hydrocarbons by means of the absorbed oxygen. 

 It may also be due to a simple loss of combustible gases and the 

 replacement of the same by non-combustible gases such as oxygen. 



(e) The rapidity or extent of this deterioration varies with 

 different coals but is probably most active during the first two 

 or three weeks from the taking of the sample, and does not seem 

 to reach a normal state till after a few months liave elapsed. 

 Further data on this point especially are necessary. 



I 



It is interesting, also, to bring together the averages of the 



results in the three tables for further comparison. There is thus 

 afforded further evidence suggesting the fact of deterioration. 



