cheap one.

I ascertained in Europe that the motive power costs 2 cents per car
mile; that is, the steam power and attendance for charging the
batteries. We have to allow twice as much for the depreciation of a
battery at the present high rate at which we have to pay for the
battery--$12 for each cell. But I believe that as soon as the storage
battery industry is sufficiently extended, the total cost for
propelling these cars will not be more than six cents a mile, or about
one half the cost of the cheapest horse traction.

I have made some very careful observations on the cable tramway in
Philadelphia, which is quite an extensive system. I have never been
able to ascertain the exact amount of waste in pulling the cable
itself; but I have it on the authority of certain technical papers
that there is a waste of about eighty per cent. I do not intend to
depreciate cable or any other tramways, but there is a difficulty
about introducing cable tramways. It is necessary to dig up the
streets and interfere with the roadways. I have been told that the
cable arrangements in Philadelphia cost $100,000 a mile, and that the
cable road in San Francisco cost more than that. One of the directors
of the cable company in Philadelphia told me that if he had seen the
battery system before the introduction of the cable, he would probably
have made up his mind in favor of the former. The wear and tear in the
case of the storage system is also considerable. There is a waste of
energy in the dynamo; secondly, in the accumulator charged by that
dynamo; thirdly, in the motor which is driven by the accumulator; and
fourthly, in the gearing that reduces the speed of the motor to the
speed required by the car axles. It would be difficult to make a motor
run at the rate of eighty revolutions per minute, which is the number