to put his toes far before him, but will acquire only such a
particular degree of space at each step or movement; but if the
shoulders have a declivity in them, he cannot only put his toes
farther before him, but a greater purchase of ground will be
obtained at every stroke.

The certainty of this effect in the declivity of the shoulders
will be known by every man's observation; and it is also easily
demonstrated by the principles of mechanics, by which we learn,
that if a weight is applied to a pulley, in order to shut a door,
and that weight be allowed to fall immediately and perpendicularly
from the door, it will not pull it too with that velocity as it
will do if an angle be acquired, and the weight pass over a wheel
removed to a very little distance from the door.

Nevertheless, there is no general rule without exception, for we
now and then find a Horse to be a good racer, who has not this
declivity in his shoulders, but from a length in his thighs and
quarters has a sufficient share of speed. Add to this, there is
another advantage obtained to the Horse besides velocity by this
declivity of the shoulders, for his weight is removed farther
back, and placed more in the center of his body, by which an
equilibrium is acquired, and every muscle bears a more equal share
of weight and action; so that the nearer the articulation of the
quarters approach to the superior part of the shoulders, so much
the shorter will the back be, and as much more expanded as the
chest is, so much stronger will the animal be, and will also have
a larger space for the organs of respiration to exert themselves.

But I would not be understood to mean, that the shortness of the