for it, it at the same time caused the ball, when hit, to bound
badly, and thus interfered with good fielding. Of course, both of these
theories become absurd in the light of the present, but it was doubtless
the belief in the former that led to the introduction of the curve. In
1869 Arthur Cummings, pitching for the Star Club, noticed that by giving
a certain twist to the ball it was made to describe a rising, outward
curve, and his remarkable success with the new delivery soon led to its
imitation by other pitchers, and finally to the general introduction of
curve pitching.

The philosophy of the curve is, in itself, quite simple. A ball is
thrown through the air and, at the same time, given a rotary motion upon
its own axis, so that the resistance of the air, to its forward motion,
is greater upon one point than upon another, and the result is a
movement of the ball away from the retarded side. Suppose the ball in
the accompanying cut to be moving in the direction of the arrow, B C, at
the rate of 100 feet per second. Suppose, also, that it is rotating
about its vertical axis, E, in the direction of I to H, so that any
point on its circumference, I H D, is moving at the same rate of 100
feet per second. The point I is, therefore, moving forward at the same
rate as the ball's centre of gravity, that is, 100 feet per second, plus
the rate of its own revolution, which is 100 feet more, or 200 feet per
second; but the point D, though moving forward with the ball at the rate
of 100 feet per second, is moving backward the rate of rotation, which
is 100 feet per second, so that the forward motion of the point D is
practically zero. At the point I, therefore, the resistance is to a
point moving 200 feet per second, while at D it is zero, and the
tendency of the ball being to avoid the greatest resistance, it is
deflected in the direction of F.

In the Scientific American of August 28th, 1886, a correspondent gave a
very explicit demonstration of the theory of the curve, and, as it has
the virtue of being more scientific than the one given above, I append
it in full.

"Let Fig. 3 represent a ball moving through the air in the direction of
the arrow, B K, and at the same time revolving about its vertical axis,
U, in the direction of the curved arrow, C. Let A A A represent the
retarding action of the air acting on different points of the forward
half or face of the ball. The rotary motion, C, generates a current of
air abo