next the ridge, unless the avenue or street is wide enough for
further subdivisions. If it is wide enough for only four or
less, the fastest vehicles must keep next the middle, and limit
their speed to the rate allowed in that section, which is marked
at every crossing in white letters sufficiently large for him
that runs to read. It is therefore only in the wide
thoroughfares that very high speed can be attained. In addition
to the crank that corresponds to a throttle, there is a gauge on
every vehicle, which shows its exact speed in miles per hour, by
gearing operated by the revolutions of the wheels.

"The policemen on duty also have instantaneous kodaks mounted on
tripods, which show the position of any carriage at half- and
quarter-second intervals, by which it is easy to ascertain the
exact speed, should the officers be unable to judge it by the
eye; so there is no danger of a vehicle's speed exceeding that
allowed in the section in which it happens to be; neither can a
slow one remain on the fast lines.

"Of course, to make such high speed for ordinary carriages
possible, a perfect pavement became a sine qua non. We have
secured this by the half-inch sheet of steel spread over a
carefully laid surface of asphalt, with but little bevel; and
though this might be slippery for horses' feet, it never
seriously affects our wheels. There being nothing harder than
the rubber ties of comparatively light drays upon it--for the
heavy traffic is carried by electric railways under ground--it
will practically never wear out.

"With the application of steel to the entire surface, car-tracks