to another, automatic motor-cars will exist, coin-worked. A man who wishes to travel will step into a motor-car, drop into a slot-machine the coin which represents the hire of the car for the distance he wants to travel, and assume control. Here again the progress of man will come into play. Everyone will know how to drive a motor-car safely. If you doubt it, consider for a moment the position of a man of 1800 suddenly transported into a street of modern London. He would never be able to cross it; the rash of omnibuses, motors and bicycles would confuse and frighten him, Imagine the same man trying to use the underground railways of to-day, or to get up to town from a busy suburb in the morning. He would either be killed out of hand or left behind altogether from sheer inability to enter the train.
We may safely suppose that the ocean ships of a hundred years hence will be driven by energy of some kind transmitted from the shores on either side. It is absolutely unquestionable that no marine engine in the least resembling what we know to-day can meet the requirements of the new age. The expense of driving a steamship increases in such a ratio to its size and speed that the economic limits of steam propulsion are foreseen. Probably the ships of A.D. 2000 will differ entirely in appearance from those we
