lt to secure sufficient tractive
adhesion on street railways during the winter season, as well as at
other times, on roads having grades of more than ordinary steepness.
As this, therefore, is probably the most important use for this
application of the electric current, it has been selected for
illustrating this paper.

I have here a model car and track arranged to show the equipment and
operation of the system as applied to railway motors. The current in
the present instance is one of alternating polarity which is converted
by this transformer into one having the required volume. The
electromotive force of this secondary current is somewhat higher than
is necessary. In practice it would be about half a volt. You will
notice upon a closer inspection that one of the forward driving wheels
is insulated from its axle, and the transformed current, after passing
to a regulating switch under the control of the engineer or driver,
goes to this insulated wheel, from which it enters the track rail,
then through the rear pair of driving wheels and axles to the opposite
rail, and then flows up through the forward uninsulated wheel, from
the axle of which it returns by way of a contact brush to the opposite
terminal of the secondary coil of the transformer. Thus the current is
made to flow _seriatim_ through all four of the driving wheels,
completing its circuit through that portion of the rails lying between
the two axles, and generating a sufficient amount of heat at each
point of contact to produce the molecular change before referred to.
By means of the regulating switch the engineer can control the amount
of current flowing at any time, and can even increase its strength to
such an extent, in wet or slippery weather, as to _evaporate any
moisture_ that may adhere to the surface of the rails at the point of
contact with the wheels while the locomotive or motor car is under
full speed.

It will be apparent that inasmuch as the "traction circuit" moves
along with the locomotive, and is complete through its driving wheel
base, the track rails in front and rear of the same are at all times
entirely free from current, _and no danger whatever can occur by
coming in contact with the rails between successive motors_. Moreover,
the potential used in the present arrangement, while sufficient to
overcome the extremely low resistance of the moving circuit, is too
small to cause an appreciable loss of current from that portion of the
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