September ii, 1919J 



NATURE 



35 



coal to produce it, we arrive at the price of 6i. 3d. 

 per ton, i.e. crediting tiie coal with half the cost. 

 The capital required to mine eight tons of coal a year 

 , m England is difficult to estimate, but it may be 

 taken approximately to be 5L, and the capital for 

 plant and machinery to convert it into electricity at 

 10/., making a total of 15L In the case of water- 

 power the average capital cost on the above basis is 

 40/., including water rights (though in exceptionally 

 favoured districts much lo,wer costs are recorded). 



[•"rom these figures it appears that the average 

 capital required to produce electrical power from coal 

 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 than 

 those in respect of coal. Another interesting con- 

 sideration is that the cost of harnessing all the water- 

 power of the world would be about 8,ooo,ooo,oooi., or 

 eciual tcH the cost of the war to England. 



Dowling has estimated the total coal of the world 

 as more than seven million million tons, and whether 

 we appraise it at i.s. or more per ton its present and 

 prospective value is prodigious. For instance, at 

 6v. 3(i. per ton it amounts to nearly one hundred 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 immediate future 

 flow in increasing qur:ntity to mining operations in 

 foreign countries rather than to the development of, 

 at any rate the more difficult and costly, water-power 

 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 molecular energy, but there is 

 another alternative which appears to merit attention. 



Bore Hole. — -In my address to Section B in 1904 

 I discussed the question of sinking a shaft to a depth 

 of tw-elve 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 pre- 

 cautions were described, 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 destrov the shaft? Sub- 

 sequent to my address I wrote a letter to Naturk, 

 suggesting that the question might be tested experi- 

 mentallv. Prof. Fr.-.nk D. .Adams, of McGill Univer- 

 sity, Montreal, acting on the suggestion, has since 

 carried out exhaustive experiments, published in ihe 

 Journal of Geology for Februarv. 1912, showing that 

 in limestone a depth of fifteen miles is probably prac- 

 ticable, and that in granite a depth of thirty miles 

 might be reached. 



Little is at present known of the earth's interior, 

 except by inference from a studv of its surface, up- 

 turned strata, shallow shafts, the velocity of trans- 

 mission of seismic disturbances, its rigidity and 

 si>ortfic gravity, and it seems reasonable to suggest' 

 that some attempt should be made to sink a shaft as 

 deep as may be found practicable and at some loralitv 

 selected bv geologists as the most likely to afford 

 useful information. 



When we consider that the estimated cost of sinking 

 a shaft to a depth of twelve miles, at present-day 

 prices, is not much more than the cost of one day 

 of the war to Great Britain alone, the expense seems 



NO. 2602, VOL. 104] 



trivial as conjpared with the possible knowledge that 

 might be gained by an investigation into this un- 

 explored region of the earth. It might, indeed, prove 

 of inestimable value to science, and also throw addi- 

 tional light on the internal constitution of the earth 

 in relation to minerals of high specific gravity. 



In Italy, at Lardarello, bore-holes have been sunk 

 which discharge large volumes of high-pressure steam, 

 which is being utilised .to generate about 10,000 h.p. 

 by turbines. At Solfatara, neaj; Naples, a similar pro- 

 ject is on foot to supply power to the great works 

 in the district. It seems, indeed, probable that in 

 volcanic regions a very large amount of power may 

 be, in the future, obtained directlv or indirectlv by 

 boring into the earth, and that the whole subject 

 merits the most careful consideration. 



While on the subject of obtaining power, may I 

 digress for a few moments and describe an interesting 

 phenomenon of a somewhat converse nature, i.e. that 

 of intense pressure produced by moderate forces 

 closing up cavities in water? 



.\ Committee was appointed by the Admiralty in 

 1916 to investigate the cause of the rapid erosion of 

 the propellers of some of the ships doing arduous, 

 duties. This was the first tmie that the problem had. 

 been systematically considered. The Committee found 

 thaC the erosion was due to the intense blows struck, 

 upon the blades of the propellers bv the nuclei of 

 vacuous cavities closing up against 'them. Though 

 the pressure bringing the water together was only 

 that of the atmosphere, yet it was proved that at the 

 nucleus 20,000 atmospheres might be produced. 



The phenomenon may be described as being 

 analogous to the well-known fact that nearly all the 

 energy of the arm that swings it is concentrated in 

 the tag of a whip. It was shown that when water 

 flowed into a conical tube which had been evacuated 

 a pressure of more than 140 tons per square inch was 

 recorded at the apex, which was capable of eroding 

 brass, steel, and, in time, even the hardest steel. 

 The phenomenon may occur under some conditions 

 in rivers and waterfalls where the velocity exceeds 

 50 ft. per second, and it is probably as great a source 

 of erosion as by the washing down of boulders and 

 pebbles Then again, when waves beat on a rocky 

 shore, under some conditions, intense hydraulic pres- 

 sures will- occur, quite sufficient of themselves to crush 

 the rock and to open out narrow fissures into caves. 



Research. — The whole question of the future 

 resources of the Empire is, I venture to think, one 

 which demands the serious attention of all men of 

 science. It should be attacked in a comprehensive 

 manner, and with that insistence which has been so 

 notable in connection with the efforts of British inves- 

 tigators in the past. In such a task some people 

 might suggest we need encouragement and assistance 

 from the Government of the country. Surelv we have 

 it. As many here know, a great experimental step 

 toward;; the practical realisation of Solomon's House 

 as prefigured by Francis Bacon in the New Atlantis is 

 being made by the Government at the present time. 

 The inception, constitution, and methods of procedure 

 of the Department, which was constituted in 1915, 

 were fully described bv Sir Fcank Heath in his paper 

 to the Royal Society of .Arts last February, and it was 

 there stated by Lord Crewe that, so far as he knew, 

 this was the only country in which a Government 

 Department of Research existed.' 



It is obvious that the work of a Department of 

 this kind must be one of gradual development with 

 small beginnings in order that it may be sound and 



3 The Italian Government are now establishing a National Council for 

 Research, and a Bill is before the t'rench Chamber for ihe establishment of 

 a National Office of Scientific, Industrial, and Agricultural Research and 

 Inventions. 



