Page:A hundred years hence - the expectations of an optimist (IA hundredyearshenc00russrich).pdf/112

 conquered ocean will unquestionably relieve the tension which is created by it, and perhaps a radical change of this character will only become possible when the enormous advantages of it have been practically exemplified.

But there is another way in which the conquest of ocean ought to prove a great economic boon to the world. Except in the case of a few coal mines, with shafts sunk near the sea beach, we have hardly at all begun to investigate the contents of the ocean floor. There is, so far as I am aware, no particular reason to doubt that the constitution of the subterranean world is in most respects very much the same under the sea as under the land. Probably vast riches, as yet undreamed of, lie below the surface of the ocean and beneath its floor. There can be no question that the needs of the world will make us eager to tap them, as we should already have begun to, if any way could be discovered of overcoming the engineering difficulties involved. These difficulties, in the present state of our knowledge, may well appal the stoutest imagination. The problem presented by the immense and paralysing air pressure in a mine at this great depth would have to be overcome. Even in some great terrestrial excavations already made the problem occurs: and where (as in river tunnels and elsewhere) men attempt to work in great air-pressures