the reduced gearing before making the change. Thus, if the calculated speed of the second gear is, say, eighteen miles per hour, the driver should wait until the work of surmounting the gradient has caused the engine to slow the pace down to that, and not try to make the change when the car is still doing twenty. Some little practice and intelligent observation is necessary before this can be nicely done, but that sort of thing is where much of the charm of driving a good car comes in.
Great care should be taken to see that both gear and bearings are kept properly lubricated, or worn surfaces will result, with much extra friction to be overcome, and if not quickly attended to other things may happen of a serious character. The driver should never allow any unusual sound emanating from the neighbourhood of the transmission gear to pass without investigation, for noise means wear or something worse; thus Mr. Claude Johnson was on one occasion driving when he noticed a knocking or clanking sound apparently proceeding from his gear-box, which upon investigation proved to be a broken pin in the differential. He at once stopped for repairs. Had he gone on, the whole gear might have got adrift and been destroyed, necessitating a costly repair and many days' loss of time.
In fig. 18 we have an example of a shaft transmission car, the type shown being the Renault, which I take not only because it was the pioneer of shaft transmission, but because the speed gearing is entirely different from anything else, and thus enables me to show a unique variation of wheel gearing. In the majority of cars which use the shaft form of transmission the variable gearing is identical in principle with that last described. In our illustration A represents the motor, b the fly-wheel with contained clutch c, and d the gear-box. At opposite ends of the centre of this are two bearings, e, e, in which two shafts, f, f, are carried, these shafts being connected in the centre by the serrated clutch g. The rearmost shaft carries a brake-drum h, within which it is attached to the universal joint i of the shaft j, the other end of the shaft carrying the second Cardan joint k and a bevel pinion enclosed
