1. The quarter elliptic, used on Ford, and similar cars, as illustrated in Fig. 2. 2. The half elliptic, Fig. 2a, which is the most widely-used form. These springs are usually attached with their front end directly to the frame, and with the rear end by means of a shackle; the center is fastened by spring clips to the axle. [Illustration: Fig. 4. Full Elliptic.] Where a distance rod is used, as on the rear axle, both ends are attached by shackles. 3. The three quarter elliptic, Fig. 3, always used as a suspension for the rear axle. This form gives more flexibility than a half elliptic, and is still stiffer so far as side motion is concerned, than the following type. 4. The full elliptic, Fig. 4, was formerly used much more than at the present time. There are also in use springs comprising a combination of half elliptic, or three quarter elliptic, on each axle, in which the front end is shackled to the frame, and the rear ends connected by shackles to another half elliptic spring, the center of which is fastened to the frame. [Illustration: Fig. 4a. Cantilever Spring.] _Fore and Aft Motion._ Provision must be made, in all cases, for the fore and aft movement of the car body which takes place in stopping or starting, and, particularly when the wheels strike an obstruction. [Illustration: Fig. 5. Fore and Aft Motion.] _Flues._ Fig. 5 shows a side view of a car, in which the dotted lines indicate the position of the body, relative to the normal, when the wheels strike an obstacle. _Lateral Motion._ In like manner when the car swings around a corner, or is traveling along a hill-side, the springs must hold the body from swinging too far. Fig. 6 illustrates, by means of the dotted lines, the side movement. It is obvious, therefore, that the springs have a duty to perform in addition to that of merely giving flexibility to the body. [Illustration: Fig. 6. Lateral Motion.] CANTILEVER SPRING.--A special form of half elliptic springs, lately developed, and of increasing use, is the cantilever spring, where the axle is attached to one end, the center of the spring being pivoted to the frame, and the other end shackled to or sliding in the frame. SHOCK ABSORBERS.--Shock absorbers are mechanical means placed between the frame and the axles for the purpose of dampening the sudden recoil of the springs after being compressed, when meeting a road obstacle. In the absence of such a device the recoil is likely to suddenly throw up the frame, body and passengers, or produce an unpleasant shock. Originally, simple leather straps were used, reaching from the body to the axle, which only limited, but did not dampen or gradually absorb the shock. Now different forms of frictional resisting toggle-levers are used, which not only absorb the shocks, but also prevent the bumping of the axle against the frame, and eliminate breaking of springs.