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 of revolutions of the street car axle when running at the rate of ten miles an hour. Take all these wastes, and you find in practice that you do not utilize more than 40 per cent. of the energy given by the steam engine. But this is quite sufficient to make this system much cheaper than horse traction.