presently contrive some sort of earthworm apparatus, so that he could go through the rocks prospecting very much as an earthworm goes through the soil, excavating in front and dumping behind, but, to put it moderately, there are considerable difficulties.  And I doubt the imaginative effect.  On the whole, I think material science has got samples now of all its crops at this level, and that what lies before it in the coming years is chiefly to work them out in detail and realise them on the larger scale.  No doubt science will still yield all sorts of big surprising effects, but nothing, I think, to equal the dramatic novelty, the demonstration of man having got to something altogether new and strange, of Montgolfier, or the Wright Brothers, of Columbus, or the Polar conquest.  There remains, of course, the tapping of atomic energy, but I give two hundred years yet before that....

So far, then, as mechanical science goes I am inclined to think the coming period will be, from the point of view of the common man, almost without sensational interest.  There will be an immense amount of enrichment and filling-in, but of the sort that does not get prominently into the daily papers.  At every point there will be economies and simplifications of method, discoveries of new artificial substances with new capabilities, and of new methods of utilising power.  There will be a progressive change in the apparatus and quality of human life—­the sort of alteration of the percentages that causes no intellectual shock.  Electric heating, for example, will become practicable in our houses, and then cheaper, and at last so cheap and good that nobody will burn coal any more.  Little electric contrivances will dispense with menial service in more and more directions.  The builder will introduce new, more convenient, healthier and prettier substances, and the young architect will become increasingly the intelligent student of novelty.  The steam engine, the coal yard, and the tail chimney, and indeed all chimneys, will vanish quietly from our urban landscape.  The speeding up and cheapening of travel, and the increase in its swiftness and comfort will go on steadily—­widening experience.  A more systematic and understanding social science will be estimating the probable growth and movement of population, and planning town and country on lines that would seem to-day almost inconceivably wise and generous.  All this means a quiet broadening and aeration and beautifying of life.  Utopian requirements, so far as the material side of things goes, will be executed and delivered with at last the utmost promptness....