Page:Popular Science Monthly Volume 57.djvu/490

480 used also as a racer. The power can be made sufficient to propel any desired load up any grade, including grades far steeper than any to be encountered on streets or highways.

The only point in which the electric vehicle suffers in comparison with the others is in the weight. The capacity of a storage battery is proportional to its weight, and if it is made light, the power derived from it will be small or the time during which it is furnished will be short. To furnish one horse power for one hour requires about one hundred pounds of battery, so that if the average consumption of energy is at the rate of two horse power, one thousand pounds of battery

will keep the vehicle in motion for five hours. The weight of batteries used in automobiles ranges from four or five hundred to about two thousand pounds, and the distance traversed without recharging varies from twenty-five to ninety miles, so that the radius of action of electric vehicles can be said to vary from about twelve to forty-five miles from the charging station.

The general arrangement of an electric carriage can be understood from Fig. 1. The rectangle shown in broken lines at A represents the storage battery. The circle B under the seat represents the controlling switch. The motor is at C and imparts motion to the axle or wheels through the gearing contained in the casing D. When the carriage