OCTOBEE 24, 1919] 



SCIENCE 



385 



interior, except 'by inference from a study 

 of its surface, upturned strata, shallow 

 shafts, the velocity of transmission of 

 seismic disturbances, its rigidity and 

 specific 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 locality 

 selected by 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 

 trivial as compared with the possible knowl- 

 edge that might be gained by an investiga- 

 tion into this unexplored region of the 

 earth. It m.ight, indeed, prove of in- 

 estimable value to science, and also throw 

 additional light on the internal constitu- 

 tion 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 

 utilized to generate about 10,000 h.p. by 

 turbines. At Solfatara, near Naples, a 

 similar project 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 ma}' 

 be, in the future, obtained directly or in- 

 directly by boi'ing 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? 



A committee was appointed by the Ad- 

 miralty in 1906 to investigate the cause 

 of the rapid erosion of the propellers of 

 some of the ships doing arduous duties. 



This was the first time that the problem 

 had been systematically considered. The 

 committee found that the erosion was due 

 to the intense blows struck upon the blades 

 of the proipellers by the nuclei of vacuous 

 cavities closing up against them. Thoiigh 

 the pressure bringing the water together 

 was only that of the atmosphere, yet it was 

 proved that at the nucleus 20,000 atmos- 

 pheres 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 feet 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 condi- 

 tions, intense hydraulic pressures 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 investigators in the past. In such 

 a task some people might suggest we need 

 encouragement and assistance from the 

 government of the country. Surely we 

 have it. As many here know, a great 

 experimental step towards the practical 

 realization of Solomon's House as pre- 

 figured by Francis Bacon in the New 



