Two commutators inclosed in a box were placed on the platforms at the two ends of the carriage, so as to be available for moving in either direction.

The accumulators were divided into four series of ten double elements, which, by means of the commutators, could be united under four combinations, viz.: 

1st. 4 series in quantity—­1 in tension. 2d. 2 " " " 2 " 3d. 3 " 4th. 4 "

Finally, a fifth movement united the four series in quantity, coupling them on each other, and putting the dynamo out of circuit, thus restoring equilibrium.  When in a state of repose, the handle was so arranged as to keep this latter switch turned on.  The accumulators were arranged for charging in two series united in quantity, each containing twenty double elements.  The charge was effected by a Gramme machine, worked by a portable engine.  Each of these series received its charge during seven hours for the ordinary service of the car, and during nine hours for the accelerated service.

The accumulators on the car actuated a Siemens dynamo, acting as a motor, such as is used for lighting, having a normal speed of 1,000 revolutions, fixed on the frame of the carriage.  The motion was conveyed from the pulley on the dynamo by means of a belt passing round a shaft fixed on movable bearings to regulate its tension, and thence to the axles by means of a flat chain of phosphor bronze.  The chain was adopted as the means of moving the axle, on account of its simplicity and facility of repair by unskilled labor.

The speed was fixed at 4 meters per second (which corresponds with a speed of nearly 9 miles per hour) for 1,000 revolutions of the dynamo; and it was regulated by cutting a certain number of the accumulators out of circuit, instead of by the device of inserting resistances, which cause a waste of energy.  By breaking the circuit entirely the motive power ceased, and the vehicle might either be stopped by the brakes or allowed to run forward by gravity, if the road were sufficiently inclined.  The reversal of the motor was effected by means of a lever which reversed the position of the brushes of the dynamo.

The dynamo could be set in motion, and the carriage worked from either end, as desired.  The handle to effect this was movable, and as there was only one handle, and this one was in charge of the conductor, he used it at either end as required.

It should be mentioned that the car was lighted at night by two incandescent lamps, which absorbed 1.5 amperes each; and the brakes also were worked by the accumulators.

The weight of the tram-car was 5,654 lb.; the weight of the accumulators was 2,460 lb.; the weight of the machinery, including dynamo, 1,232 lb.  The car contained room for fourteen persons inside and twenty outside.  Under the conditions of the competition the car was required to draw a second car occasionally.