188 CHYMISTRY APPLIED TO AGRICULTURE. 



must be so conducted that the dissolvent may be received 

 into an alembic or close vessel. 



In addition to the methods of preserving fruits by drying, 

 and by reducing their juices to the state of sirups and jellies 

 by natural or artificial heat, M. de Montgolfin has applied 

 the action of the air pump with great success. I have tast- 

 ed juices prepared and thickened in this manner, and I 

 thought they were much superior to those that had been 

 evaporated in either of the modes hitherto usually practised. 

 I do not doubt that, when this method becomes better known, 

 it will be generally adopted. 



ARTICLE II. 



On the Preservation of the Fruits of the Earth hy Se- 

 cluding them from the Action of Air, Water, and Heat. 



The atmospheric air coming in contact with fruits de- 

 prives them of their carbon, and forms carbonic acid. 



Fruits exposed to the solvent action of water suffer decom- 

 position by having the affinity existing between their con- 

 stituent principles weakened, and at length destroyed. 



Heat dilates the particles of bodies, and thus diminishes 

 the forces of cohesion and attraction, and favors the admis- 

 sion of air and water. 



The combined action of these three agents produces 

 very speedy decomposition ; the effect produced by any 

 one of them is slower, and the results different. So that 

 in order to preserve fruits from decomposition it is neces- 

 sary to guard them from the power of these three de- 

 stroyers. 



In several European countries, particularly in the north, 

 roots of all kinds are preserved merely by secluding them 

 entirely from air, heat and water ; this is done by digging 

 deep ditches in a dry soil upon a spot a little elevated, and 

 depositing in them the roots, which are afterwards cov- 

 ered over with a layer of earth, of sufficient thickness to 

 prevent them from suffering by the frost; over the whole 

 is then laid a bed of straw, broom, or fern, in order to pro- 

 tect them from rain and from the water of melting snows 

 which might filtrate through into the pit. 



