LIQUID MANURE IN POT CULTURE. 
141 
ON THE APPLICATION OF MANURE IN A LIQUID 
FORM TO PLANTS IN POTS. 
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 
Saussure to be dependent, to a great extent, upon the com¬ 
ponent 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 con¬ 
fined in a pot to a small quantity of mould, till it becomes ex¬ 
hausted, proves sufficiently the truth of this position. I have 
shown in a former communication, that a seedling plum-stock, 
growing in a small pot, attained the height of 9 ft. 7 in. 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 soil. But the quantity of earth which a small 
pot contains soon becomes exhausted relatively to one kind of 
plant, though it may be still fertile relatively to others ; and the 
size of the pot cannot be changed sufficiently often to remedy 
this loss of fertility ; and, if it were ever so frequently changed, 
the mass of mould which each successive emission of roots would 
enclose must remain the same. Manure can therefore probably 
be most beneficially given in a purely liquid state ; and the 
quantity which trees growing in pots have thus taken under my 
care, without any injury and with the greatest good effect, has 
so much exceeded every expectation I had formed, that I am 
induced to communicate the particulars and the result of my 
experience. 
I for some years appropriated a forcing-house at Downton to 
the purposes of experiment solely upon fruit trees, which, as I 
had frequent occasion to change the subjects upon which I had 
to operate, were confined in pots. These were at first supplied 
with water in which about one tenth by measure of the dung 
of pigeons or domestic poultry had been infused, and the quan¬ 
tity of these substances (generally the latter) was increased 
from one tenth to a fourth. The water, after standing forty- 
