Mr. Knight on the Motions 
$16 
position of the sun, so that the light reflected might continue 
to strike the tendrils; which then receded from the glass, and 
appeared to be strongly repulsed by it. 
The tendrils of the ampelopsis very closely resemble those 
of the vine, in their internal organization, and in originating 
from the alburnous substance of the plant ; and in being, under 
certain circumstances, convertible into fruit stalks. The claws, 
or claspers, of the ivy, to experiments upon which I shall now 
proceed, appear to be cortical protrusions only; but to be 
capable (I have reason to believe) of becoming perfect roots, 
under favourable circumstances. Experiments, in every re- 
spect very nearly similar to the preceding, were made upon 
this plant ; but I found it necessary to place the different sub- 
stances, to which I proposed that the claws should attempt to 
attach themselves, almost in contact with the stems of the 
plants. I observed that the claws of this plant evaded the 
light, just as the tendrils of the ampelopsis had done; and 
that they sprang only from such parts of the stems as were 
fully, or partially, shaded. 
A seedling plant of the peach tree, and one of the arnpe- 
lopsis and ivy, were placed nearly in the centre of the house, 
and under similar circumstances ; except that supports, formed 
of very slender bars of wood, about four inches high, were 
applied to the ampelopsis, and ivy. The peach tree continued 
to grow nearly perpendicularly, with a slight inclination to- 
wards the front and south side of the house, whilst the stems 
of the ampelopsis and ivy, as soon as they exceeded the height 
of their supports, inclined many points from the perpendicular 
line, in the opposite direction. 
It appears therefore that not only the tendrils and claws of 
