1816.} On the upright Growth of Vegetables. 449 
in an opposite direction.” By this law the lunar and antilunar tides. 
are raised ; the lunar by direct, the antilunar tide by resisted, attrac- 
tion ; and when we recollect that no other cause is known whereby 
any particle of matter is made uniformly to ascend in a straight line 
from the centre, can we hesitate to adopt the opinion that this is 
the law to which we are to ascribe the upright growth of vegetables? 
The most difficult part of the problem, however, remains behind 
—the investigation of those subtile influences by which this law 
operates on vegetables; and my confidence, though unshaken as to 
the general principle, diminishes as I proceed in offering an opinion 
as to the mode of its agency. 
_ Let us premise some facts, the result of minute observation. 
Having in the month of June marked some young shoots of the 
spruce fir, the beech, and the thorn, which were all very much 
deflected, wires were fitted to their respective shapes, and by means 
of these wires I was enabled to delineate the different stages of 
straightening in all the twigs. (See Plate L.) After minutely 
examining them, I was satisfied that they had exhibited the 
same phenomena which would naturally have resulted from the 
mechanical operation of a great many threads attached to different 
points, and employed to elevate in parallel lines all the parts-of the 
plants. In such a case the plant would gain the perpendicular 
position, not by any recurvature at the top, but by a general and 
progressive movement of the whole; the lower parts being affected, 
not only by the direct attraction of the threads attached to them, 
but also by § 2ir connexion with the upper parts, which would draw 
the lower ones along with them. ‘The influence of gravitation, 
whether direct or resisted, may with much propriety be compared 
to the agency of a force operating by such parallel threads. ‘They 
truly represent the lines of attraction ; and as they represent also 
the agency by which these vegetables acquired perpendicularity, 
they exhibit to the mind a tangible idea of the principle which regu- 
Jates the process. 
Having watched the growth of a garden bean, and taken every 
morning an accurate sketch of its progress, the process of straight- 
ening from the semicircular position, in which the germen first 
appeared, till it attained perpendicularity, exactly corresponded 
with the observations made on the other plants, with this additional 
circumstance, that its progress seemed to be less rapid when its 
position was nearly horizontal, than when it was inclined either 
upwards or downwards ; a circumstance accurately according with 
the principles of gravity, which would find the greatest counter- 
action from the gravity of the plant, when the stem was in a hori- 
zontal position, 
The effect here described may be produced by a buoyant prin- 
ciple bearing up the plant in which it is inclosed, as the hydrogen 
gas bears and presses upward the body of a balloon; or, by drawing 
it upwards, in consequence of its adhesion, as the balloon, rendered 
buoyant by the gas, carries up the car which is attached to it, La 
