We referred just now to the tricycle made by Messrs. De Dion and Bouton, and shown by them at the competition of 1895, although it was not entered for the race. Since that time they have made two types of this class of vehicle, of which we give engravings in Figs. 12 and 13. In the former the motor is attached to the back of the frame by a suspended connection. It will be seen that the frame is not a little complex, and necessarily so, in order that it may carry the different parts of the mechanism. The motor has a single cylinder and is quite inclosed in a casing that is kept filled with oil; the moving parts of the engine are within this casing; the main shaft drives, by means of a pinion, the differential gear that is mounted on the axle. It will be seen from the illustration that the builders do not rely wholly on the motor, but have provided the usual cycle pitched chain so that, in the event of a breakdown, the rider can propel his machine with the pedals. Indeed, this is always necessary in starting, though a few strokes with the pedals suffice, and as soon as the engine is started the pedal clutch is thrown out of gear. In mounting a steep gradient the pedals are also useful as an auxiliary to the motor. The mechanical power provided is sufficient to drive the machine on a good and level road at the rate of 20 kilometers an hour. It can also travel up grades of 1 in 20 or 25; the weight of the machine in working order is only 100 lb. On referring to the engraving there will be seen attached to the frame beneath the saddle a rectangular reservoir that contains the gasoline, the capacity being sufficient for a six hours' run. To the reservoir is attached the carburetor, which is connected to the motor by a pipe. The explosive mixture in the cylinder is fired electrically, and for this purpose a compact and reliable battery is hung to the forward part of the frame almost beneath the steering bar. This battery will give 100 hours of work without recharging; it supplies current to a Ruhmkorff coil placed beneath the rear bar of the frame in a metal case that can be seen in the engraving; the other cylinder near it is a pressure reducer into which the gases from the cylinder are exhausted before they pass into the air. The second type of tricycle, illustrated by Fig. 13, is an improvement on the first. It will be seen that the frame is much simpler; the total weight is reduced; the gasoline reservoir is triangular, in order to economize space. The motor employed is very ingenious, and appears to be efficient; we have seen it in operation at the works of MM. De Dion and Bouton. It can be run easily at a speed of 2,500 revolutions, although in practice the rate is limited to 700 revolutions, in order to reduce the wear of the moving parts. In this, as in the earlier type, the use of water for cooling the cylinder is avoided, the outside of the latter being made with a number of wings that are intended to keep the cylinder cool by