SECT. II. PHYSICAL PHENOMENA. 2$ 



tion shall accidentally happen to have been in- 

 verted, so as that the radicle shall be above and 

 the plumelet beneath, the former will then bend 

 itself down till it gets a hold of the soil ; and the 

 latter will, in like manner, bend itself upwards till 

 it reaches the air. And no human art has ever 

 been able to make them assume contrary direc- 

 tions, or to convert the one into the other, as the 

 root and branch of the vegetating plant may be 

 afterwards converted. Du Hamel, whom no phy- 

 tologist has surpassed in the invention of expedients 

 to unmask or to control the operations of the ve- 

 getative principle, instituted a variety of experi- 

 ments with a view to effect this conversion, but 

 failed in them all. He first placed an acorn be- 

 tween two wet sponges suspended from the ceiling 

 of his room, so as that the radicle was uppermost 

 and the plumelet undermost. The result however 

 was that the radicle after bursting its integuments 

 assumed a downward direction, and the plumelet 

 in its turn an upward direction, till each had 

 gained its natural position. He then filled a tube 

 with earth, and planted also an acorn in it, ip ail 

 inverted position. But the radicle and plumelet 

 had no sooner escaped from their envelopes than 

 they began to assume their natural direction as 

 before. He then filled another tube with earth, 

 of a diameter so small, that an acorn, when placed 

 in it, touched the sides of the tube. It was planted 

 in its natural position, and allowed to remain so 



