SPECIAL METHODS OF DISTRIBUTION. 99
both motors were constructed with a larger factor of
safety for temporarily enduring high voltage than is now
the custom.
There is no” momentous difficulty in the way of build-
ing a motor to work regularly at 700 to 750 volts, and still
less in producing one to stand that pressure for temporary
running. And motors which will stand 750 volts at a
pinch can safely be operated two in series on 1000 volts
with a quite moderate rheostat capacity.
Of course, the question of safety enters into any and
all plans for operating at increased voltages.
Of 500 volt currents it can safely be said that they
have never caused the death of a human being in normal
health. Of shocks to employes there are thousands yearly
and the author has yet to hear of a fatal one. The deaths
from this cause heralded in the newspapers generally turn
out to have been due to other causes. One loudly proclaimed
from Maine to California, was due to a gasoline explosion
in a car house, another to a collision with an electric rail-
way pole, and so on.
Whether thisimmunity may be extended to double the
usual voltage is decidedly open to question. Currents of
750 to 1000 volts cannot on the other hand be classed as
extremely dangerous. In any case there is no good reason
why they should not be freely employed with good con-
struction and proper inspection. In interurban work the
tendency is for the road to own its right of way as in the
case of steam roads, and in such case any desired voltage
ought to be permitted, provided it be installed with due
precautions.
T'o summarize the matter, there is no sufficient reason,
electrical, mechanical or ethical, why roads of the inter-
arban class should not be regularly operated at from 700 to
1000 volts, either with special motors or with special ar-
rangements for series running.
A rise from 500 to 750 volts would more than cut
the cost of copper in two, while retaining at least the effi-
ciency reached at the lower voltage. At 1000 volts more
