CHEMISTRY IN RELATION TO 1IORTTCULTT RE. 



107 



importance alike for supplying the bulk and the nourishment of vegetable 

 life. To the horticulturist this does not present the same difficulties as 

 it does to the farmer ; for, while the latter^is dependent on the natural 

 and varying rainfall, the gardener can practically control the supply in 

 any way he may like. This may not apply so fully in the case of what 

 is grown in the open as, e.g., in a vegetable garden, but at all events the 

 gardener is much better off in this respect than the farmer. Different 

 plants have their several requirements, each of which should be studied, 

 and the giving or withholding of moisture be exercised accordingly. So 

 too is it with heat, this again being, to a considerable extent, within 

 the power of the gardener, whereas the farmer is dependent entirely on 

 natural sun and warmth, and subject to cold and wind, frost and snow. 



Altogether, then, the gardener's position is a much more artificial 

 one ; he is able to make more use of external aids, and so the serious 

 considerations affecting the agriculturist in the matter of dew, rainfall, 

 drainage, &c, have not so much significance for the horticulturist. Still, 

 there are points of similar application to both, for, in the preparation 

 and cultivation of land, be it for farm or for garden, efficient drainage 

 in the case of the heavier soils, and sufficient retentive power for moisture 

 in lighter ones are absolute necessities. 



Want of proper drainage will cause stagnation to ensue and bring about 

 a coldness of the soil which will hinder the process of oxidation and the 

 other agencies at work in the soil, whereas land properly drained will be 

 warm and porous, ready for the easy penetration of the root and root-fibres, 

 and possessed of the conditions requisite for the entrance of oxygen and 

 for the free exercise of the processes resulting in the supply of plant-food. 

 On the other hand, land devoid of matter capable of holding moisture in 

 sufficiency will tend to "burn." The retention of water is very different 

 in different soils, and depends upon the fineness of division of the 

 particles ; a gravel or sand retains the least moisture, a loam more than 

 a clay, anH a humus or peaty soil the most. Similarly the gravel or 

 sandy soil loses its moisture most readily, and a clay soil less so ; while, 

 in order to prevent rapid evaporation from the surface, a thorough 

 cultivation of the soil, to obtain it in a fine and loose condition, is most 

 desirable. 



Closely associated with the question of the supply of moisture is the 

 consideration of the different kinds of water used by the horticulturist. 

 It is to be feared that often one water is regarded like another, and 

 though there may be a general impression that one kind is softer or 

 harder than another, little is done, as a rule, to ascertain what the 

 differences are, or whether there may be that in the usual supply which 

 may make it injurious to or unsuitable for plants. Taking the number 

 of samples that have been submitted to me by members of the Society 

 for analysis, it is true that the larger proportion of these have been of 

 waters. But in the great majority [of cases the application has been 

 made in respect of their use as drinking waters, and not primarily for 

 horticultural purposes. Still, there are instances in which useful in- 

 formation has been obtained, and where explanation 7of difficulties that 

 have arisen has been found. It is generally, and very rightly, believed 

 that rainwater is, all round, the best for horticultural purposes, but the 



