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212 scrutiny to prevent wear or the loss of nuts and pins. The buyer should avoid a car with insufficient strength or quality of work in these parts. This form of axle, known in this country as the Ackerman axle, though invented by M. Lankensperger in 1818, is of very great value in motor construction, as the ordinary carriage front axle, with locking plate and centre pins, would not only be extremely inconvenient, but it would not give so stable a car under the higher speeds at which cars are driven round corners, the wheel base with Ackerman axles remaining nearly the same when turning a corner as when running straight.

These advantages are obtained with the disadvantage of the jointed short arm at each end with its attendant joint pin, nuts, and lynch-pin and lubricator. These are not really any trouble except to those who look upon anything with more machinery than a wheel-barrow as being complicated, and they should not of course undertake to run an automobile. There are numerous forms of this axle, differing in form of pivot and as to the method of holding the road wheel on the axle, which in the form shown is kept in place by a washer and nut and a split pin. All these details are like those of well-known forms of carriage axles, but some, such as the Wolseley car axles, run in ball bearings, and these any cyclist will soon understand. The strength of the fork is much increased by the firm holding together of the two jaws by the pin, and hence it is necessary to see that the nut at the bottom is so used that it does hold the jaws together, and it must not be allowed to become loose.

The hind axles of nearly all the chain-driven cars is a fixed axle similar to but stronger than ordinary carriage axles, and they require the same but more frequent attention. The driving wheels on these axles have sprocket wheels fastened to them, and are driven by chains which run upon them and on the smaller sprocket wheels or pinions on the ends of a spindle which is driven by the motor. This spindle is in two parts, connected by gearing, which is known as differential or