114 CAUSE OF MOTION IK PLANTS. 



other atmospheres. It is by the light refracted in this pas- 

 sage, that we see the globes from which it emanates. 



I am, Sir, with great esteem, 

 You is, &c. 



J. B. van MONS. 



Remaining Proof of the Cause of Motion in Plants ex- 

 plained; and tvhat is called the Sleep of Plants shoivn to 

 be Relaxation only. By Mrs. Agnes Ibbetson. 



To Mr. NICHOLSON. 

 SIR, 



Cause of mo- .OlNXIOUS to complete the proofs of that idea sug- 



^on in plant.. ^ es t e( ] m m y ] as t paper, concerning the motion of plants; 

 and to show, that I should not have endeavoured to call the 

 attention of the public to this subject, had I not possessed 

 what appeared to me to be the most incontrovertible argu- 

 ments in its favour, with the most solid reasons for believ- 

 ing, not only " that this leatherlike substance and the 

 spiral wire are the cause of motion in plants," and of every 

 degree of irritability (which I was at rirst fearful of ad- 

 vancing), but that " they are also the cause of what has 



Nofeelinror heen mistaken for the sleep of plants." In short, this ap- 

 pears to me perfectly to explain all that has hitherto been 

 considered as feeling or volition in plants, and to resolve it 

 into mechanical power ; and the complete management of 

 the spiral wire. The interior formation of plants, when 

 duly magnified by the solar microscope, proves the vegeta- 

 ble world to be composed of machines governed wholly 

 by light and moisture; and dependant on these causes for 

 motion. 



Spiral wire. The spiral wire may be considered as a secondary cause, 



acted upon by the two first ; and by its means all the move- 

 ments of the plant are m-de, the flower opens and shuts in 

 the morning and evening, the leaves turn, or the creeping 



plants 



volition in 

 plants. 



