30 
Hence all bodies placed above the surface of the 
earth fall to it in right lines, which, if produced, 
would pass through its centre ; and a body falling 
near a high mountain, is a little bent out of the 
perpendicular direction by the attraction of the 
mountain, as has been shown by the experiments 
of Dr. Maskelyne on Schehallien. 
Gravitation has a very important influence on 
the growth of plants ; and it is rendered probable, 
by the experiments of Mr. Knight, that they owe 
the peculiar direction of their roots and branches 
almost entirely to this force. 
That gentleman fixed some seeds of the garden 
bean on the circumference of a wheel, which in 
one instance was placed vertically, and in the other 
horizontally, and made to revolve, by means of 
another wheel worked by water, in such a manner, 
that the number of the revolutions could be regu- 
lated ; the beans were supplied with moisture, and 
were placed under circumstances favourable to 
germination. The beans all grew, notwithstanding 
the violence of revolution, which was sometimes as 
much as 250 revolutions in a minute on the ver- 
tical wheel, which always revolved rapidly, and 
with little variation of velocity ; the radicles, or 
roots, pointed precisely in the direction of radii in 
whatever direction they were first placed. The 
germs took precisely the opposite direction, and 
pointed to the centre of the wheel, where they 
soon met each other. Upon the horizontal wheel, 
the conflicting operation of gravitation and centri- 
fugal force, occasioned the germs to form a cone, 
more or less obtuse, according to the velocity of 
