SENSATION OF PLANTS. 
49 
ducted the quantity of carbonic acid belonging to it, as deter- 
mined in experiment 1, its proportion of water of crystalliza- 
tion was found to be 20 75 grains. 
From this statement it therefore becomes evident, that the Summary of 
composition of 100 parts of fossil natron is as follows : 
44-25 
2425 
2075 
1’25 
9-50 
100*00 
Muriate of platina, and several other tests, indicated the 
absence of all foreign bodies in the solutions, expts. L and 2, 
which, after being evaporated, yielded pure nitrate of soda. 
This variety of natron, when exposed to the atmosphere, *^ c * oes not 
does not, like the common sub-carbonate of soda, obtained by 
artificial processes, effloresce, a circumstance which unques- 
tionably must be attributed to the comparatively small portion 
of water of crystallization which it contains, and to the com- 
plete saturation of its alkaline base with carbonic acid. 
5 , Nassau Street , Soho , 
April 13 th, 1813 . 
IX. 
On the Sensation and Perception of Plants . 
To Mr. Nicholson . 
SIR, 
I AM induced to offer a few remarks on the undecided 
question of the existence or non-existence of vegetable 
sensation and perception, though I cannot, for my own part, 
even give an opinion on a subject in which so much discussion, 
and so many opposing arguments and facts are involved. 
I confess I think, that the circumstances of the tendrils Motion or 
bending towards neighbouring supports, and their twining f e e *drps°vven 
Vol, XXXV.— No. 161. E round 61 
Carbonic acid 
Soda 
Water of crystallization . . 
Sulphate of soda 
Muriate of soda 
component 
parts. 
