Then there is another question which, I believe, has hitherto escaped notice, and that is, as to whether we should not make some alteration in the kinds of manure so as to suit them better to the various aspects we have to deal with, for even in land of the same quality, and treated in precisely the same way, there is a considerable difference in the appearance of the coffee when we pass from an eastern or southern aspect to a western one, and a very great and marked difference is at once perceptible when you enter the coffee on a northern aspect. In the last-named case the coffee is nearly always green, and steadily but slowly growing, while on the southern and eastern aspects the coffee in the hot weather is apt to present a dried-up and sickly appearance. Then on these two last-named aspects there is commonly an over supply of suddenly grown wood. We should therefore, I think, increase foliage-stimulating manures on northern aspects, and diminish them on the southern and eastern, while we should have a medium degree of such manure in the case of western aspects. It seems to me that the reasoning in favour of foliage-stimulating manures on northern aspects is the same as in the case of coffee trees under direct tree shade, which always prevents the rapid growth of new wood. But on this point, as well as on that in the previous section, experiments must be made before any definite conclusion can be arrived at.
The quantity of manure that should be annually supplied is evidently a matter of the greatest importance, and here the first thing to be borne in mind is that of the four manures we require, namely, lime, nitrogen, phosphoric acid, and potash, the first two are somewhat easily removed from the soil, while the last two are firmly retained by it. It is evident, then, that lime and nitrogen should be applied little and often, while phosphoric acid and potash may be applied either little and often, or in large quantities at longer intervals, whichever may be found most convenient. But in the opinion of an eminent agricultural chemist whom I have specially consulted on the subject, nitrogen, if applied in slowly decomposing form, as for instance, in the shape of oil-cake, would only be lost in an infinitesimal degree, but still he admits that there would be a loss, and as we cannot tell what that loss may amount to under the influence of our tropical climate and deluges of rain, it would be safe to assume that nitrogen, as well as lime, should be put down at short intervals and, in order to make up for the escape of these manures from the soil, in larger proportions than either phosphoric acid or potash.