But by the process I have recommended much more shade will be left than will ultimately be required, and I have found that it is impossible to clear down at once all the trees you wish to get rid of, as, if you did, you would be sure to require such a number of piles as would, when they were burnt, be sure to injure the trees to be preserved.  It is therefore necessary to complete the clearing during the season following.  Such trees, then, as you may wish further to remove may be thrown down between the rows of coffee, and others which may be likely to do much damage, either to the coffee or to the shade trees to be preserved, may be lopped and barked, and they should be barked as high up as a man can reach, as we have found that trees barked close to the ground die slowly.

It sometimes, however, happens that the forest land is much cut up with narrow and deep ravines, and in that case the bottoms of such ravines should be cleared off entirely, and this can be done without injury to the standing trees above, as, when the wood in the bottom of the ravine is being burnt the flames will be too distant to inflict any injury to the trees left for shade higher up the slopes, but, as I have said, great care must be taken to prevent any running fire through the shaded land; and I can speak of the effect of such a fire from a melancholy experience.  In the event of bottoms of ravines being thus cleared down, it may afterwards be found desirable to supply fresh shade on the southern and western slopes, and this can easily be done on the system recommended previously for lands which have been entirely cleared down.

It is time now to turn our attention to the extremely complicated question of the quantity of shade required for the various aspects, gradients, and soils we have to deal with, and let us in the first place begin with some remarks on the effects of aspect as regards heat.

In considering, then, aspect as regards sun and heat, I may observe that it is impossible to exaggerate the importance of taking into account the immense variation in temperature on the different exposures.  For the effect that the sun’s rays have on certain aspects in heating the soil and drying up the plant, are such as would be extremely difficult to believe, had the facts not been verified by competent observers, and with the aid of the thermometer.  And as regards northern and southern slopes in particular, we shall find that the difference between one exposure and the other is just what constitutes the difference between green and dried grass, and between leaves luxuriantly green and leaves dry and withered.  And that the first is literally true may be seen by anyone in the months of January and February, for in these months you will see grass on northern aspects green, and, comparatively speaking, fresh, while, even in a valley sheltered from drying winds, the grass on the southern slopes is completely withered.  And you will see an equally striking difference in the coffee plants—­those