which has made aerial travel more difficult to perfect than it would be
in our world.

The main traffic, both passenger and freight, is carried on by the Tube
Line, a wonderful system perfected through thousands of years of
painstaking labor.

Two immense tubes, lying side by side, each ten feet in diameter, made
of a substance more durable than steel, form the road bed of this
lightning system of travel. The cigar-shaped cars have hard
rubber-wheels and fit over raised bars all around on the inside of the
immense Tube.

The motor power is called Sky-rallic, and is communicated throughout the
whole Tube Line by Brosis, a porous metal running in thin narrow bands.

This Tube Line runs without a curve from one division of the road to
another, except in rare cases where a bend is absolutely necessary. In a
mountainous region I noticed a stretch of Tube Line without a bend
running sixty miles, according to our measurement. On prairies, the
unbroken stretches are much longer.

The cars in this Tube Line travel with fearful rapidity. It requires two
or three miles to reach dashing speed, after which a run of fifty miles
is made in eight or ten minutes. No precaution need be taken by the
motorman as nothing can get into the tube and only one train is allowed
in a section at one time. Certain hours are given to passenger traffic
and others to freight traffic. An immense amount of freight can thus be
carried in one hour. It is possible to send a through freight car two
thousand miles in ten or twelve hours. Express cars are never connected