Jenjitive ^al'ity of the Averrhoa Carambola. ^rp 



the leaves is diiferent from that of other pinnated plants. In 

 the lafl: a great uniformity iubfifls in the reiped:iv^e polition of 

 the leaves on the pinna ; but here fome will be {zzvi on the 

 horizontal plane, ^fome raifed above it, and others fallen under 

 it ; and in an hour or io, without any order or re2;ularity, whicii 

 I could obferve, all thefe vv'ill have changed tlieir relpedive 

 pofitions. I have feen a leaf, which was high up, fall down ; 

 this it did as quickly as if a ftrong impreflion had been made 

 en it, but there was no cauie to be perceived. 



Cutting the bark of the branch down to the wood, and even 

 feparating it about the fpace of half an inch all round, fo as to 

 flop all communication by the veffels of the bark, does not for 

 the firll: day affe6l the leaves, either in their polition or their 

 aptitude for motion. 



In a branch, which T cut through in fuch a manner as to 

 leave it fufpended only by a little of the bark no thicker than a 

 thread, the leaves next day did not rife fo high as the others ; 

 but they were green and frefh, and, on being touched, moved, 

 but in a much lefs degree than formerly. 



After fun-fet the leaves go to lleep, tirfl moving down {o as 

 to touch one another by their under iides ; tliey therefore per- 

 form rather more extenfive motion at night of themfelves than 

 they can be made to do in the day-time by external imprehions. 

 With -a eonvex lens I have collected the rays oi the fun on a 

 leaf, fo as to burn a hole in it, without occalioning any motion- 

 But when the experiment is tried on the petiolus, the motion is 

 as quick as if from flrong percuflion, although tlie rays were 

 not fo much concentrated as to caufe pain when applied hi the 

 fame degree on the back of the hand j. nor had the texture .of 

 the petiolus been any ways changed by this ; for next Hay it 



Vol. LXXV. B b b / could 



