230 SCIENCE IK SHORT CHAPTERS. 



most porous of the strata. Streams of cold water could thus be 

 poured down the sides of the shaft, which, on reaching the bottom, 

 would flow by a downhill road into the workings. The stream of air 

 rushing by the same route and becoming heated in its course would 

 powerfully assist the evaporation of the water. The deeper and 

 hotter the pit, the more powerful would be these cooling agencies. 



As the specific heat of water is about five times that of the coal- 

 measure rocks, or the coal itself, every degree of heat communicated 

 to each pound of water would abstract one degree from five pounds 

 of rock. But in the conversion of water at 60 into vapor at say 

 100, the amount of heat absorbed is equivalent to that required to 

 raise the same weight of water about 1000, and thus the effective 

 cooling power on the rock would be equivalent to 5000. 



The workings once opened (I assume as a matter of course that by 

 this time pillar-and-stall working will be entirely abandoned for long- 

 wall or something better), there would be no difficulty in thus pour- 

 ing streams of water and torrents of air through the workings during 

 the night, or at any suitable time preparatory to the operations of 

 the miner, who long before the era of such deep workings will be 

 merely the director of coal cutting and loading machinery. 



Given a sufficiently high price for coal at the pit's mouth to pay 

 wages and supply the necessary fixed capital, I see no insuperable 

 difficulty, so far as mere temperature is concerned, in working coal at 

 double the depth of the Eoyal Commissioners' limit of possibility. 

 At such a depth of 8000 feet the theoretical rock-temperature is 183. 



By the means above indicated, I have no doubt that this could be 

 reduced to an air temperature below 110 that at which Mr. Tyn- 

 dall's shampooers ordinarily work. Of course the newly-exposed 

 face of the coal would have its initial temperature of 183 ; but this 

 is a trivial heat compared to the red-hot radiant surfaces to which 

 puddlers, shinglers, glassmakers, etc. are commonly exposed. 

 Divested of the incumbrance of clothing, with the whole surface of 

 the skin continuously fanned by a powerful stream of air which, 

 during working hours need be but partly saturated with vapor a 

 sturdy midland or north-countryman would work merrily enough at 

 short hours and high wages, even though the newly-exposed face of 

 coal reached 212 ; for we must remember that this new coal-face 

 would only correspond to the incomparably hotter furnace-doors and 

 fires of the steamship stoke-holes. 



The high temperature at 8000 or even 10,000 feet would present a 

 really serious difficulty during the first opening of communication 

 between the two pits. A spurt of brave effort would here be neces- 

 sary, and if anybody doubts whether Englishmen could be found to 

 make the effort, let him witness a "pot-setting" at a glass-house. ^ 

 Negro labor might be obtained if required, but my experience among 

 English workmen leads me to believe that they will never allow 

 negroes or any others to beat them at home in any kind of work 

 where the wages paid are proportionate to the effort demanded. 



If I am right in the above estimates of working possibilities, our 

 coal resources may be increased by about forty thousand millions of 

 tons beyond the estimate of the Commissioners. To obtain such an 

 additional quantity will certainly be worth an effort, and unless we 

 suffer a far worse calamity than the loss of all our minerals viz. a 

 deterioration of British energy the effort will assuredly be made. . 



