254 
SUCCULENT PLANTS. 
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that no frost may ever be able to operate upon them. The times at which fire-heat 
will be required are, of course, those at which frost prevails ; and unless this is 
absolutely occurring, or pretty certain indications of its appearance are afforded, 
artificial heat would only be prejudicial. 
On the soil most congenial to the subjects of this paper, it will now be expedient 
to offer a few remarks. The earth used by the major half of culturists has been 
already characterized as unsuitable, on account of its tendency to acquire an 
impervious degree of hardness when suffered to become more than moderately dry. 
It has further been stated, that sand is a far better constituent than brick rubbish 
or any similar substance, because, if well incorporated with the other materials, it 
will prevent their coherence into an indurated mass, and admit the constant 
percolation of any fluids that may be applied. The quality and quantity of sand 
which it is desirable to make use of have therefore yet to be mentioned. 
Nurserymen and the higher classes of cultivators invariably incorporate with 
the soil for which an admixture of sand is essential, a white silvery substance, the 
particles of which are extremely minute, and which, when perfectly dry, will not 
adhere to each other, or to common earth. By blending this to a sufficient extent with 
any compost, it is kept continually open, porous, and permeable ; and no amount of 
aridity will render it of that firm solid consistence which it would otherwise attain, 
and which equally opposes the circulation of water and the extension of the roots. 
Two of the principal objects to be gained in potting succulents are, first, a soil 
that, however dry it may once become, or however long it may be retained in that 
state, will, on the ultimate application of water, readily permit its diffusion 
throughout the whole body ; and secondly, one that will never offer resistance to 
the finest rootlets, nor, if left till it is very arid, and then removed for the purpose 
of shifting the specimen, will so attach itself to the roots, or conglomerate into large 
balls, as to render the operation of disengaging the former difficult and dangerous. 
It has been previously asserted that none of these plants are very bountifull)?^ 
provided with roots ; and hence, whatever cuts off their supply of nutriment, 
or helps to damage or break them, is especially to be deprecated. 
Connecting the circumstances last described with the properties above assigned 
to sand, there will no longer be any hesitation in the mind of the gardener 
concerning its adoption as an invaluable ingredient in his compost. Heduced brick- 
rubbish is by no means of a like nature, being itself, in a great measure, incapable 
of keeping the earth duly open, and totally unfit for obviating its cohesion, owing 
to the impossibility of making it fine enough to spread it thoroughly through the 
mass. There is a substance, however, which is a finer kind of what is commonly 
called river-sand, and consists of exceedingly small pebbles, which, if easily 
procurable, is even more useful than silver sand. Its value is attributable to the 
increased porosity it imparts to the soil with which it is mixed, and the 
consequently rapid dispersion of fluids it occasions. It follows that this should 
have the preference where it can be obtained. 
