262 SOILS, MANURES, &c. 
like falts, in the form of cryftals ; con- 
fequently the parts of the plant replete 
with juices, burft on freezing, and are 
deftroyed. 
Succulent plants are therefore more 
liable to injury from froft, than fuch as 
are of a more firm, hard, and woody 
texture. 
Froft has a fimilar effefl on the aque¬ 
ous particles of the earth: on freezing 
it becomes more feparated, and capable 
of imbibing more copioufiy, the nitrous 
acid of the air, which abounds moft in 
cold and frofty weather, particularly 
when the wind is northerly. 
The beft method of preparing foil for 
a compoft is as follows, viz. 
Take the turf, with its earth and 
fibres, about three or four inches thick, 
from the furface of a common, or old 
pafture field, where the foil is of a good 
2 quality, 
