nally test the manure.

From what I have said as to the composition of castor cake, it is probable
that white castor contains from 4 to 5 per cent. of phosphate of lime, and
I desire to call particular attention to this, because oil-cake is usually
regarded purely as a nitrogenous source of manure, whereas one of the
oil-cakes commonly used--i.e., castor cake--contains an appreciable
quantity of that phosphate of lime of which bones are generally considered
to be the sole suppliers by the planter. But it is evident that if we
annually used 300 lbs. per acre of white castor, we should, even if it
contained only 4 per cent. of phosphate of lime, be supplying six times
the amount of lime and more than three times the amount of phosphoric acid
removed by an average crop of coffee, and though the lime is liable to
loss from waste, it must be remembered that the phosphoric acid is firmly
retained by the soil. It is important to remember that castor cake should,
like bones, be mixed with a considerable quantity of fine top soil, so
that the manure may be widely distributed through the soil.

Nitrate of potash, or saltpetre, is an extremely expensive manure, and not
a desirable one, because the nitrogen in it is in a too quickly
assimilable form, and is very liable to be lost in drainage. But it might
be used with effect, and in small quantities, for bringing forward
supplies, and I am informed that for this purpose it has been used with
advantage in Coorg. I have used the nitrate of potash on my property--an
experimental amount only--and it caused the trees to throw out strong and
numerous shoots. It should be bought in the form of pure nitre.

Nitrate of soda is also liable to the objection that the nitrogen in it is
in a too quickly available form, and liable to be lost. I have never used
it on my property, but from observing its effect on an estate in Coorg,
and the effect it had in causing the trees to throw out a fine supply of
young wood, can see that it might be used with great effect in rapidly
forcing forward worn-out coffee growing on an exhausted soil. But if used
for this purpose it should be backed up with a liberal supply of bones and
castor cake, or of bones and farmyard manure, or bones and top soil, as,
if not so backed up, the result would be unsatisfactory, if not
disastrous, seeing that the nitrate of soda, if applied alone, would cause
the plant to wring out everything that was available in the soil. The