384 



SCIENCE 



[N. S. Vol. L. No. 1295 



portion of the wealth and revenue. From 

 this point of view the present value of un- 

 mined coal seems not to have been suffi- 

 ciently appreciated in the past, and that 

 in the future it should be better appraised 

 at its true value to the nation. 



This question may be viewed from an- 

 other aspect by making a comparison of 

 the cost of producing a given amount of 

 electrical power from coal and from water- 

 power. Assuming that 1 h.p. of electrical 

 energy maintained for one year had a pre- 

 war value of £5, and that it requires about 

 «iglit tons of average coal to produce it, 

 we arrive at the price of 6s. 3d. per ton, 

 *. e., crediting the coal with half the cost. 

 The capital required to mine eight tons of 

 eoal a year in England is difficult to esti- 

 mate, but it may be taken approximately 

 to be £5, and the capital for plant and 

 machinery to convert it into electricity at 

 £10, making a total of £15. In the case of 

 water-power the average capital cost on 

 the aibove basis is £40, including water 

 rights (though in exceptionally favored 

 districts much lower costs are recorded). 



From these figures it appears that the 

 average capital required to produce elec- 

 trical power from eoal is less than half 

 the amount that is required in the case of 

 water-power. The running costs, however, 

 in connection with water-power are much 

 less tlian those in respect of coal. Another 

 interesting consideration it that the cost of 

 harnessing all water-power of the world 

 would be about £8,000,000,000, or equal to 

 the cost of the war to England. 



Dowling has estimated the total coal of 

 the world as more than 7 million million 

 tons, as whether we appraise it at Is. or 

 more per ton its present and prospective 

 value is prodigious. For instance, at 6s. 

 Sd. per ton it amounts to nearly one hun- 

 dred times the cost of the war to all the 

 belligerents. 



In some foreign countries the capital 

 costs of mining are far below the figures 

 I have taken, and, as coal is transportable 

 long distances and, generally speaking, 

 electricity is not so at present, therefore it 

 seems probable that capital will in the im- 

 mediate future flow in increasing quantity 

 to mining operations in foreign countries 

 rather than to the development of, at any 

 rate the more difficult and costly, water- 

 powder schemes. When, however, capital 

 becomes more plentiful the lower running 

 costs of water-power will prevail, with the 

 result that water-power will then be 

 rapidly developed. 



As to the possible new sources of power, 

 I have already mentioned moleculai* 

 energy, but there is another alternative 

 M'hich appears to merit attention. 



Bore Hole. — In my address to Section B 

 in 1904 I discussed the question of sink- 

 ing a shaft to a depth of twelve miles, 

 which is about ten times the depth of any 

 shaft in existence. The estimated cost was 

 £5,000,000, and the time required about 

 eighty-five years. 



The method of cooling the air-locks to 

 limit the barometric pressure on the 

 miners and other precautions were de- 

 scribed, and the project appeared feasible. 

 One essential factor has, however, been 

 queried by some persons: Would the rock 

 at the great depth crush in and destroy 

 the shaft? Subsequent to my address I 

 wrote to Nature, suggesting that the ques- 

 tion might be tested experimentally. Pro- 

 fessor Prank D. Adams, of McGill Uni- 

 versity, Montreal, acting on the suggestion, 

 has since carried out exhaustive experi- 

 ments, published m the Journal of Geology 

 for February, 1912, showing that in lime- 

 stone a depth of fifteen miles is probably 

 practicable, and that in gi-anite a depth of 

 thirty miles might be reached. 



Little is at present known of the earth's 



