ELISHA MITCHELL SCIENTIFIC SOCIETY. 1^0 



evidently a step in the process of nitrification, in that 

 nitrog'en is fixed in a form available to the plant. If, 

 indeed, nitrates are neither produced by the org-anisms 

 before this absorption takes place, nor within the plant 

 by the action of the cells, it is certainly converted into 

 a nitrifiable compound. It is only from a study of the 

 results of the life action of these micro-org-anisms that 

 the important role which the}" play in the man}" chang'es 

 taking' place in nature has been discovered. 



THE EXHAUSTION OF THE COAL SUPPLY. 



F. P. VEXABIvE. 



Bodies of scientific men, as the British Association 

 for the Advancement of Science, and v^arious public 

 prints have for some time been discussing* the problem 

 of the earth's coal supply and its probable exhaustion. 

 There is a g-rowing- uneasiness on the part of the pub- 

 lic that the end of our supply of coal is in sig^ht and 

 that we are in dang-er of running' short of fuel. If the 

 ag"itation of the question would correct the present 

 enormous waste of fuel and lead to proper economy in 

 its use, the gain would be g-reat. The vast waste in 

 coke ovens, the loss in crude furnaces, in imperfect en- 

 gfines and wretched heating- appliances is enoug'h to 

 make any thoug'htful man stand agfhast. For instance, 

 a hig-h authority tells us that the loss in our heating- 

 stoves, g-rates etc., is 80 or 90 per cent, that is, one 

 ton of coal should last us nine or ten times as long- as it 

 does now or do that much more work. A family now 

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