soil more than a good dose of mud from ponds and ditches, which supplies at once humus, alumina, and silicates, and gives ‘staple’ to the soil, while preventing it also from ‘burning.’  In the manuring of sandy soils great care is requisite, because of their absorbing power.  In the bulb-growing districts of Holland, manure from cowsheds is worth an enormous price for digging into loose sand for a crop of Potatoes, to be followed by bulbs.  Sandy soils are generally deficient in phosphates and alkalies; hence it will on such soils be frequently found that kainit (a crude form of potash) and superphosphate of lime will conjointly produce the best results, more especially in raising Potatoes, Onions, and Carrots, which are particularly well adapted for sandy soils.  Probably one of the best fertilisers is genuine farmyard manure from stall-fed cattle, for it contains phosphates, alkalies, and silicates in available forms.  For similar reasons Peruvian Guano is often useful on such soils.  Artificial manure should be selected with a view to correct the deficiencies of the soil, and to satisfy the requirements of the crops to be grown on it.

While we have thus dealt principally with the Inorganic or mineral constituents of plants, and the way in which the deficiencies of the soil in respect of any of them may be supplied by artificial applications, we must not ignore the other class of constituents, the Organic.  These are supplied almost entirely from the atmosphere itself, though, to a limited extent, the presence in the soil of humus or vegetable matter contributes also.  Yet this latter, as seen in the case of land heavily dressed with farmyard or stable manure, vegetable refuse, &c, exercises important functions in other directions.  Not only are mineral constituents, in forms available for assimilation, supplied, but soils so treated derive peculiar advantages as regards their mechanical state and improved physical conditions, chiefly in respect of retention of moisture, warmth, &c.  Thus, sandy soils, which are very apt, through poverty in humus, to lose their moisture readily and to ‘burn,’ are rendered more retentive of moisture and fertilising constituents by the use of farmyard manure, &c., and have more ‘staple’ or substance given to them, while heavy, tenacious clays are opened out, lightened, and rendered more amenable to the influences of drainage, aeration, &c., and so become less cold and inactive.

For the present purpose the principal garden crops may be grouped in two classes, in accordance with their main characteristics and the predominance of certain of their mineral elements.  The figures given on the following page show the average percentage proportions of the several minerals in the ashes of the different plants.