OF PLANTS. 205 



and the other downward."* Were this account better 

 verified by experimentt than it is, it only shifts the con- 

 trivance. It does not disprove the contrivance ; it only re- 

 moves it a little further back. Who, to use our author's 

 own language, " adapted the objects 1" Who gave such 

 a quality to these connate parts, as to be susceptible of dif- 

 ferent " stimulation ;" as to be ** excited," each only by its 

 own element, and precisely by that, which the success of 

 the vegetation requires ? I say, ** which the success of the 

 vegetation requires," for the toil of the husbandman would 

 have been in vain ; his laborious and expensive preparation 

 of the ground in vain ; if the event must, after all, depend 

 upon the position in which the scattered seed was sown. 

 Not one seed out of a hundred would fall in a right di- 

 rection. 



Our second observation is upon a general property of 

 climbing plants, which is strictly mechanical. In these 

 plants, from each knot or joint, or as botanists call it, ax- 

 illa of the plant, issue, close to each other, two shoots ; 

 one, bearing the flower and fruit, the other, drawn out into 

 a wire, a long, tapering, spiral tendril, that twists itself 

 round any thing that lies within its reach. Considering, 



ed powers are soon distinctly developed. The cotyledons expand, the 

 membranes burst, the radicle acquires new matter, descends into the 

 soil, and the plume rises towards the free air. By degrees, the organs 

 of nourishment of dicotyledonous plants become vascular, and are con- 

 verted into seed leaves, and the perfect plant appears above the soil. 

 Nature has provided the elements of germination on every part of the 

 surface ; water and pure air and heat are universally active, and the 

 means for the preservation and multiplication of life, are at once simple 

 and grand." Sir H. Davy's Elements of Agricultural Chemistry^ 

 ii. ed. p. 70. Paxton. 



* Darwin's Phytologia, p. 144. 



t " Gravitation has a very important influence on the growth of 

 plants ; and it is rendered probable, by the experiments of Mr. Knight, 

 that they owe the peculiar direction of their roots and branches al- 

 most entirely to its force. 



" That gentleman fixed some seeds of the garden bean on the cir- 

 cumference of a wheel, which in one instance was placed vertically, 

 and in the other horizontally, and made to revolve by means of another 

 wheel worked by water, in such a manner, that the number of the re- 

 volutions could be regulated ; the beans were supplied with moisture, and 

 were placed under circumstances favourable to germination. The 

 great velocity of motion given to the wheel was such, that it perform- 

 ed 250 revolutions in a minute. It was found that in all cases the 

 beans grew, and that the direction of the roots and stems was influenced 

 by the motion of the wheel. When the centrifugal force was made 

 superior to the force of gravitation, which was supposed to be done 

 when the vertical wheel performed 150 revolutions in a minute, all the 



