3 03 
the Radicle and Germen of Seeds, 
diminishing the rapidity of the motion of the horizontal 
wheel, the radicles descended more perpendicularly, and the 
germens grew more upright ; and when it did not perform 
more than 80 revolutions in a minute, the radicle pointed 
about 45 degrees below, and the germen as much above, 
the horizontal line, the one always receding from, and the 
other approaching to, the axis of the wheel. 
I would not, however, be understood to assert that the 
velocity of 250, or of 80 horizontal revolutions in a minute 
will always give accurately the degrees of depression and 
elevation of the radicle and germen which I have mentioned; 
for the rapidity of the motion of my wheels was sometimes 
diminished by the collection of fibres of conferva against the 
wire grate ; which obstructed in some degree the passage of 
the water : and the machinery, having been the workmanship 
of myself and my gardener, can not be supposed to have 
moved with all the regularity it might have done, had it been 
made by a professional mechanic. But I conceive myself to 
have fully proved that the radicles of germinating seeds are 
made to descend, and their germens to ascend, by some ex- 
ternal cause, and not by any power inherent in vegetable 
life : and I see little reason to doubt that gravitation is the 
principal, if not the only agent employed, in tins case, by 
nature. I shall therefore endeavour to point out the means 
by which I conceive the same agent may produce effects so 
diametrically opposite to each other. 
The radicle of a germinating seed (as many naturalists 
have observed) is increased in length only by new parts 
successively added to its apex or point, and not at all by any 
