273 
acting merely as one of its earthy ingredients. Quicklime, when 
it becomes mild, operates in the same manner as chalk ; but in 
the act of becoming mild, it prepares soluble out of insoluble 
matter. It is upon this circumstance that the operation of lime 
in the preparation for wheat crops depends ; and its efficacy in 
fertilizing peats, and in bringing into a state of cultivation all 
soils abounding in hard roots, or dry fibres, or inert vegetable 
matter. The solution of the question, whether quicklime ought 
to be applied to a soil, depends upon the quantity of inert vege- 
table matter that it contains. The solution of the question, 
whether marl, mild lime, or powdered limestone, ought to be 
applied, depends upon the quantity of calcareous matter already 
in the soil. All soils are improved by mild lime, and ultimately 
by quicklime, which do not effervesce with acids ; and sands 
more than clays.” 
•20 Liquid Manure, to Plants in Pots. The late president 
of the London Horticultural Society was a really practical hor- 
ticulturist, and all his experiments were guided by principles so 
philosophic that they will not cease to be useful, even if his 
practice be obsolete. In carrying out our intention of gather- 
ing all useful knowledge on the subject of IManures, a paper of 
Mr. Knight’s claims attention, although written many years ago. 
He was in advance of his contemporaries. His reasoning and 
practice will encourage horticulturists in the use of Liquid 
Manure, which seems to us most desirable. He says: — “ The 
quantity of earth, which the most firm and solid parts of trees 
afford by analysis, is well known to be very small ; and even the 
species of these earths have been proved, by the younger Saus- 
sure, to be dependent, to a great extent, upon the component 
parts of the soil, in which the trees happen to have grown. A 
large extent and depth of soil seem therefore to be no further 
requisite to trees than to afford them a regular supply of water, 
and a sufficient quantity of organisable matter ; and the rapid 
growth of plants of every kind, when their roots are confined in 
a pot to a small quantity of mould, till that becomes exhausted, 
proves sufficiently the truth of this position” 
“I have shown that a seedling plum-stock, growing in a small 
pot, attained the height of nine feet seven inches, in a single 
season; which is, I believe, a much greater height than any 
seedling tree of that species was ever seen to attain in the open 
237. lUCTABIVH. 
