No very startling difference in the durability of these two heads has as yet developed itself. The telescope is often hung in balls, which makes it work as freely as the Stanley, if not more so; it has also a little advantage in appearance; still, a large majority of the makers have adopted the Stanley, probably because it is a little cheaper and quite as efficient. There seems to be less disadvantage in the slant of the front fork than might have been expected. According to an old theory in the Ordinary, the more nearly vertical the head, the less “sensitive” the steering; but experience demonstrates that by practice all machines are so easily steered that the point is really not so vital. The original Rover machine as put upon the market has everything combined to give it a full slant in the neck; that is to say, it has a large thirty-six-inch front wheel and no curve to the fork, while in other machines of the same general pattern a thirty-inch front wheel is used with considerable curve to the fork, which taken together make the neck almost vertical; riders, however, are equally satisfied with either style. It will be well to notice here that though I speak of the curve of the fork in relation to steering, it really has necessarily nothing to do with it, since a perfectly straight fork could have a more vertical head bearing than one much curved. The slant of the pivotal line is the important feature, and this may be varied in either by bending the fork or, in the Stanley, by setting back the lower bearing. The four drawings below show necks of equal slant and considerable variation in the curve or shape of the forks. [Illustration: Rear-driver front forks. Fig. 1 Fig. 2 Fig. 3 Fig. 4] Any of the four patterns above work exactly the same in the hands of the rider. So much for the manner of obtaining slant of the head or pivotal connection, as we shall call it; but as to the amount of this slant it is desirable to obtain much more can be said. The great system of castering, so knowingly discussed by some expounders of cycling faith, has in it really something of substantial importance. It is asserted that if the machine is so constructed that the line of pivotal connection strikes the ground in front of the point of contact of the wheel (see Fig. 1), a castering element comes into play which will cause the machine to retain its forward course, and enables the rider to go “hands off.” Note that the line _a b_ strikes at _c_ in front of _d_. [Illustration: Fig. 1 Supposed caster.] [Illustration: Fig. 2 Real caster.] I have observed many rear-drivers, and cannot see that this makes much difference; the various kinds seem to be equally well ridden, with respect to easy steering, if only the riders happen to be thorough experts; of course all sorts of theories in regard to the action of the steering have been advanced.