liable to be killed during the winter. Generally these should be avoided; but in the hands of a skilful cultivator, with a judicious selection of varieties and proper pruning, the result may be more favorable.

CHAPTER II.

ORIGIN AND PROPERTIES OF SOILS.

SOILS THE RESULT OF DISINTEGRATION-CAUSES STATED BY SIR H. DAVY - BOUSSINGAULT-HITCHCOCK · -ALLUVIAL AGENCIES. PROPERTIES:

SPECIFIC GRAVITY-AFFINITY FOR MOISTURE -ABSORPTION OF MOISTURE FROM THE AIR-CAPILLARY ATTRACTION STATE OF DIVISION -COHESION AND ADHESION ABSORPTION OF GASES FROM THE ATMOSPHERE-ABSORPTION AND RETENTION OF HEAT.

THE

HE earth presents a great diversity of soils, upon which widely different kinds of plants flourish, each adapted to some peculiar genus, species, or variety of plant in the vegetable kingdom. The failure of one orchard, while another, receiving the same treatment, succeeds, evinces the necessity of a proper selection of the land for the growth of fruit.

"All soils are the result of the disintegration and decomposition of rocks, with the addition of saline and decayed vegetable and animal substances." The materials derived from the rocks constitute by far the larger part, and therefore by an examination of these we can form an idea of the composition of the soil produced from them. Soils may be almost wholly composed of disintegrated rocks, in which

case the ingredients of the earth which result from them will maintain their original character; but if these are decomposed, their relations may be changed. Soils do not always contain those substances alone which are found in the rocks of their immediate neighborhood, for by the action of diluvial currents the loose matter of different rocks is frequently intermingled, while sometimes the foreign entirely covers the native material. Alluvial land is formed by the deposits of streams, and has in its composition the substances inherent in the various rocks through which it has passed. Peaty soils are mostly the result of the decay of vegetable matter, and have but little of the components found in the original rocks. The fertility of soils depends in a great measure upon its admixture and subdivision. An earth, if it may be properly so called, composed entirely of pebbles, would not support vegetation. Coarse sand may be knit together by the roots of a few plants, but in a fine state of division and decomposition it can nourish almost any plant. The benefit resulting from the mixture of soils is shown by the fact that those lands formed from the decomposition of conglomerate rock are very fertile. Dr. Hitchcock, in his "Geological Survey of Massachusetts," says that soils consist, "first, of their earthy and metallic ingredients, which are mostly silicates; secondly, the acids, alkalies, and salts which existed originally in them, or are introduced by cultivation;

and thirdly, of the water and organic matter which they contain. The latter constitutes the principal nourishment of plants derived from the soil, while the salts are necessary to prepare that nourishment to be taken up and assimilated by their delicate vessels. The earth serves as a basis of support for the plant, as a receptacle for the nourishment, and probably also, in connection with the roots, as a galvanic combination for the development of those electrical agencies by which the food of plants is taken up and converted into vegetable matter. Soils, to be fertile, should contain silica, allumina, and lime, and should be in a good state of subdivision, as this has much influence on the retention of moisture. The proportion of earthy materials is not of so much importance, if they are only present, because the amount consumed is so small compared with the humic acid, or organic remains. Dr. Dana aptly says that the earths are the plates, the salts the seasoning, and the geine (or humic acid) the food of plants." Cultivation does not materially alter the natural composition of the earths, but it modifies its salts and humic acids. Plants cannot flourish without this latter element. Alluvial and sandy diluvial contain the least of it, and should therefore be supplied with manure; the crops then gathered may be even larger than those from a soil in which it naturally exists, because such lands, being porous, the atmosphere is able to

penetrate and prepare the whole of it for the nourishment of plants. The amount possessed will not necessarily effect the first crop; but it may soon become so exhausted that it will not produce another. Upon the amount of humic acid which is contained in the soil will depend the length of time in which it will continue to produce good crops.

Humus, by absorbing oxygen from the atmosphere, is able to furnish the plant with carbonic acid, which is thus produced, and also with oxygen. While there are soils which are unfertile from want of humus, yet this element, which exists in such vast quantities in the peaty deposits of swamps, would, if mixed with them, render all such fertile. Dr. Dana says that "the fact that peat, or turf, is very soluble in alkali, seems not to be known among our farmers. The usual practice of mixing lime with peat is decidedly the worst which can be followed, as the geine, which forms the largest part of peat bogs, forms with lime a compound which is very insoluble. With allumina geine forms a compound still more insoluble than with lime; and though the vegetable matters in combination with these earthy bases are actually absorbed by the roots of growing plants, still the geine is in a state much less favorable than when in combination with alkali. If we mix the lye of wood ashes with peat, we form a dark-brown vegetable solution; the alkaline properties are completely neutralized by the