principle does not demand that the hoops should
stand absolutely erect.

Similar means will, no doubt, be tried for the achievement of a
modified form of what has been dreamt of by cyclists under the name of
a unicycle. This machine will resemble a bicycle running on the inner
rim of a hoop, and will probably attain to a higher speed for show
purposes than the safety high-geared bicycle of the usual pattern. But
it is in the development of goods traffic along ordinary roads that
the hoop-rail principle will make its most noticeable progress. By its
agency not only will the transport of goods along well-made roads
become less costly and more expeditious, but localities in sparsely
settled countries--such as those beyond the Missouri in America and
the interior regions of South Africa, Australia and China--will become
much more readily accessible.

A traction-engine and automobile which can run across broad, almost
trackless plains at the rate of fifteen miles an hour will bring
within quick reach of civilisation many localities in which at
present, for lack of such communication, rough men are apt to grow
into semi-savages, while those who retain the instincts of
civilisation look upon their exile as a living death. It will do more
to enlighten the dark places of the earth than any other mechanical
agency of the twentieth century.

CHAPTER VI.

SHIPS.

The "cargo slave" and the "ocean greyhound" are already differentiated
by marked characteristics, and in the twentieth century the divergence
between the two types of vessels will become much accentuated. The
object aimed at by the owners of cargo boats will be to secure the
greatest possible economy of working, combined with a moderately good
rate of speed, such as may ensure shippers against having to stand out
of their capital locked up in the cargo for too long a period. Hence
cheap power will become increasingly a desideratum, and the possible
applications of natural sources of energy will be keenly scrutinised
with a view to turning any feasible plan to advantage. The sailing
ship, and the economic and constructive lines upon which it is built
and worked, will be carefully overhauled with a view to finding how
its deficiencies may be supplemented and its good points turned to
account. One result of this renewed attention will be to confirm, for
some little time, the movement which showed itse