‘ 
282 On a Method of Freezing at a Distance. 
astonishing that a cellule surrounded with wood should 
extend, notwithstanding the obstacle thus presented to it. 
Every organized body is developed, and increases by”a very 
powerful force, and the plant in developing itself breaks a 
very strong thread tied firmly round it. 
Every cellule is a separate organ, destined to preserve and 
prepare the sap, to furnish it to other parts. The super- 
fluity penetrates into the meatus intercellulares, and resem- 
bles animal fat a little. The green matter which colours 
the plant is always in the cellules. It resists the action of 
water, but it is dissolved in alcohol: this solution is not 
precipitated by water like that of the resins. All the co- 
Jouring matter of the leaves, the flowers, and the fruits, is 
contained in the cellules, as well as the acid, sweet, astrin- 
gent or saline juices, &c. Finally, we therein find the 
starch, which forms small grains, and the mucilage, which 
sometimes forms small grains, sometimes small crystals, 
and occasionally it is fluid. Chemical analysis has dis- 
covered to me some very remarkable varieties between 
the mucilages of plants, which I shall mention in another 
place. 
[To be. continued. ]} 
XLVII. On a Method of Freezing at a Distance. By 
Witiiam Hype Wo ttaston, M.D. See. R.S.* 
Tuar a fluid, from which a portion is evaporated, be- 
comes colder in consequence of the heat absorbed by 
that part which assumes the gaseous state; that fluids 
rise in the state of vapour at a lower temperature when the 
pressure of the atmosphere is removed, and consequently 
may be cooled to a lower degree by evaporation im vaeuo 
than in the open air, are facts too well known to need 
confirmation before the Members of this Society by any 
new experiments, 
Nevertheless, a new mode of applying the most esta- 
blished principles may-deserve to be recorded, if it assist 
the illustration of them, and be instructive from the no- 
velty of the view in which it exhibits a certain class of 
phenomena; although no immediate use be at present 
proposed, to which it can be applied with advantage. 
If an attempt were made to freeze water by evaporation, 
without other means than the vacuum of an air-pump, the 
pump must be of the best construction; and though the 
* From the Philosophical Transactions for 1813, part i. 
quantity 
