13 
to our uses a more advantageous receptacle may not be found. 
But without extending the inquiry so far as tliis, if it be once 
admitted that earth is in no wise the tbod of plants, then, ceeteris 
paribus, Xhe most unproductive sand, for instance, the heaths 
of Surrey, may be rendered as productive as the Golden Valley : 
we have only to make use of this sand, as nature intended it, for 
a rece[)tacle of roots, and then having learned what is the true 
food of jilants, to supply that food in the most profitable way. 
It is now generally admitted that carbonic acid gas is the food 
of plants; but leaving even this question lo those more compe- 
tent to decide on it correctly, it is quite certain that their food, 
whatever it may be, is evolved in greater quantities from certain 
chemical preparations than from the richest and most highly 
manured earth. Poverty of soil thus becomes a nonentity : 
rotation of crops a mere amusement : once admit that earth is 
simply a receptacle for roots, and you invest it with a property 
which you cannot wear out. Every common and heath may 
be made to produce wheat at the will of the cultivator, and the 
supply must ere long greatly exceed the consumption ; that 
very description of food, the supply of which causes such diffi- 
culty to all our legislators, becoming more abundant than our 
most zealous philanthropists could desire. 
28 Pear-trees, to make freitfcl. As we proceed with the 
Frifitist, the subjects of which it is destined to treat, branch out 
and exhibit more and more the importance of increased atten- 
tion on the part of the fruit grower. .Although it may be but a 
single tree that he has lo manage, even this, in proportion to 
his knowledge and attention, will be made matter of pleasure 
and profit. The following paper, submitted to the Horticultu- 
ral Society by its late president, T. A. Knight, Esq., indicates 
principles, of the advantages of which the cultivator may avail 
himself in other ways than those to which they are applied in 
the experiments detailed. 
“ The pear-tree exercises the patience of the planter during a 
longer period before it affords fruit, than any other grafted tree 
which finds a place in our gardens; and though it is subse- 
quently very long-lived, it generally, when trained to a wall, 
becomes in a few years unproductive of fruit, except at the 
extremities of its lateral branches. Both these defects are, 
however, 1 have good reason to believe, the result of improper 
2i7. Al’CTARlUM. 
