410 VEGETATION OF SEED9, 



Probability J conccivcd, that if gravitation were the cause of Cue 



that trial might . ^ - 



be made of descent of the radicle, and of the ascent of the geimen, it must 



this by con- ji^t either by its immediate influence on the vegetable fibres 

 staiit chani!;e of , •' _ _ _ "_ 



tiie position of ^^y vessels during their formation, or on the motion and con- 

 the seed. sequent distribution of the true sap afforded by the cotyledons ; 



and as gravitation would produce these effects only whilst the 

 seed remained at rest, and in the same position relative to the 

 attraction of the earth, I imagined that its operation would 

 become suspended by constant and rapid change of the position 

 of the germinating seed, and that it might be counteracted by 

 the agency of centrifugal force. 

 Beans werefas- Having a strong riil of water passing through my garden, 

 p*osUio\"s tothe ^ constructed a small wheel, similar to those used for grinding 

 riicumference corn, adapting another wheel of a different construction, and 

 revolvhi<^"^ ' formed of very slender pieces of Mipod, to the same axis, 

 wheel. Round tlie circumference of the latter, which was eleven inches 



in diameter, numerous seeds of the garden bean, which had 

 been soaked in water to preduce their greatest degree of ex- 

 pansion were bound, at short distances from each other. The 

 radicles of these seeds were made to point in every direction ; 

 others as tangents to its curve ; some pointing backwards, and 

 others forwards, relative to its motion ; and others pointing in 

 opposite directions in lines parallel with the axis of the wheels. 

 The whole was inclosed in a box, and secured by a lock, and 

 a wire grate was placed to prevent the ingress of any body 

 capable of impeding the motion of the wheels. 

 ~ which-per- The water being then admitted, the wheels performed some- 

 formed 150 ic-^|^jj,„ more than 150 revolutions in a minute ; and the position 

 volutions ma'' ^ 



minute. of the seeds relative to the earth was of course as often per- 



fectly inverted within the samfe period of time ; by which^I 

 conceive, that the influence of gravitation must have been 

 wholly suspended. 

 The seeds grew In a few days the seeds began to germinate ; and as the truth 



with the ger- ^j- gQj^g ^f the opinions I had communicated to you, and of 



mens directed ' j ' 



to the centre, many Others which I had long entertained, depended on the 



and the radi- result of tlie experiment, I watched its progress with some 



cles 10 the op- ' ' i o 



positedirec- anxiety, though not with much apprehension; and 1 had soon 



*^"^"" the pleasure to see that the radicles, in whatever direction they 



were protruded from the position of the seed, turned their points 



outwards from the circumference of the wheel, and in their 



subsequent 



