hermaphrodite iiowers ; but by laic observations, it 

 has appeared, that some trees bear male, some female 

 flowers. Yet there is a Tast variety. In Chelsea gar- 

 den, some hollies bear female, some hermaphrodite 

 flowers ; but some trees bear only male flowers, some 

 only femajc, some only hermaphrodite; others bear 

 both male and female, both male and hermaphrodite, 

 or female and hermaphrodite, and others bear male, 

 female, and hermaphrodite, all at the same time. 



15. That the leaves of certain plants assume at night 

 a disposition different from that of the day, is well 

 known. This has been usually termed the Sieep. 

 But to what is this owing ? Not to the variation of heat 

 or cold, moisture or dryness. For however these are 

 varied, the same thing happens with equal regularity.. 

 It is light alone that occasions this change, which by 

 the smallness of its particles is capable of entering 

 bodies, and by its activity of producing great changes 

 in them. It changes the position of the leaves of 

 plants, by a motion it excites among the fibres. The 

 natural position of the lobes in these leaves is droop* 

 ing: this is their posture of repose. But vegetation is 

 very imperfectly performed, while they remain in it. 

 It is light which liters that position by its quick vi- 

 brations. 



In the evening, August 7, (in order to make a full 

 experiment) Dr. Hill placed a plant of Abrus, in a 

 room where it had moderate day-light, without the 

 sun shining upon it. The lobes of the leaves were 

 then fallen perpendicularly from the middle rib, and 

 closed together by their under sides ; thus they con* 

 tinned all night. Half an hour after day. break they 

 began to separate, and a quarter of an hour after sun- 

 rise, were perfectly expanded. Long before suruset 

 they began to droop again, and toward evening were 

 closed as at first. 



JNext day the plant was set where there was Jesa 

 light. The lobes were raised in the morning, but not 

 80 much, and they drooped earlier at evening. 

 VOL. ii, H 



