whether with the cheaper or the more expensive form. Thus the cycle will do much to popularise motoring.
For all practical purposes the motor cycle comes under the Light Locomotives Act of 1896 and the Local Government Board regulations by which its speed is restricted to twelve miles an hour. Restive horses and policemen must also be respected, and the motor cyclist must halt upon a signal from the driver of the former or the raising of the hand of the latter. Lights must be carried as on ordinary bicycles. In addition to observing these regulations, the owners of motor quadricycles, tricycles, or bicycles must take out licences at the cost of 2l. 2s. in the case of the quadricycle, and of 15s. in that of the others. Efficient brakes must also be provided.
Apart from machines now regarded as curiosities, the motor tricycle of MM. de Dion and Bouton was the most successful form of vehicle introduced after the adaptation of the internal combustion engine to road locomotion. The first made had a small 34-horse-power motor fixed to the rear axle, the carburetter being placed behind the main down tube to the frame. The size of the motor was gradually increased, until we now find tricycles in ordinary use with air-cooled motors of 234-horse-power capacity. Of a similar design was the Phoebus tricycle fitted with the Aster motor. It differed only in minor points from other machines, and in the use of copper radiating gills tightly fixed on the cylinder of the motor, the advantage of which (as Mr. Worby Beaumont remarks) is not very apparent. The Beeston tricycle was the first of the kind English- made throughout, but the Ariel motor tricycle was the first really successful English machine. It shows several variations in design from the original De Dion. Notably, the motor, instead of being placed to the rear of the back axle, is placed forward of it. A single case fills up the whole of the space in the main frame, and contains the battery, carburetter, and petrol tank. There are a few other motor tricycles, but their main features are on the lines of the above.
Passing to motor bicycles, they are of such recent develop-
