the roofs of houses; though it is sometimes used for paving cellars, kitchens, areas, &c.
Tiles are divided into various sorts, according to the purposes to which they are applied. Thus, Plain tiles are chiefly used for covering houses; and, by the 17 Edw. IV. c. 4, they ought to be 1012 inches in length, 612 in breadth, and 5-8ths of an inch in thickness.—Ridge-tiles are of a semi-cylindrical form, and, by the statute, must be 13 inches in length, and also 612 inches in breadth: they are chiefly laid on the ridges of houses.—Corner-tiles are first made flat, in the manner of plain tiles, excepting that they are quadrangular; the two sides forming right lines; and their ends, arches of circles: previously to burning, they are bent on a mould, like ridge-tiles; and ought to be 1012 inches in length, and of a convenient size, being generally placed on the corners of roofs.
There are many other sorts, known under the names of Dutch, or Flanders, crooked, pan-tiles, &c.: but as only those first-mentioned are at present employed for cleaning knives, &c. we shall merely add, that on importation, they pay a duty of 15s. 5d. per thousand.
Lastly, the manner of working the clay, and burning the tiles, being nearly similar to that followed in the manufadture of Bricks, we refer the reader to vol. i, pp. 348-49.
TILLAGE, in agriculture and gardening, denotes the different methods of moving the ground, by means of a plough, spade, or other implement, to a certain depth, so as to bring the soil to the surface, and to turn the upper part downwards; in consequence of which, the earth is less liable to be exhausted by the growth of weeds or useless plants.
The proper time for this operation, varies according to the nature of the soil: thus, in horticulture, hot and dry ground should be tilled, either immediately before or after rain; but, if the weather be very dry, it ought not to be stirred, unless it be speedily irrigated: in the contrary case, when the earth is strong, moist, and cold, it will be useful to employ the spade, &c. diaring the hottest weather.
In agriculture, the cold, moist, clayey, or stiff soils, generally require to be tilled three times, namely, in the spring, in summer, and at seed-time, for wheat; and four times, for barley.
The great advantages arising from tillage, consist, 1. In the pulverization of the soil, so that its nature may eventually be changed, and the toughest clay be rendered as light or friable as common earth; and, 2. In eradicating noxious weeds, by exposing their roots and stalks to the joint action of the air, moisture, and heat, by which they are converted into manure. On these principles, indeed, the new, or horse-hoeing huslandry, chiefly depends; and, though perhaps some agriculturists may have extolled rather too highly, the benefits derived from frequent stirring of the ground, yet it cannot be denied, that such practice greatly contributes to the improvement of the soil, especially when combined with the judicious application of manures.
Having already, at some length, described the various modes of cultivating the soil, the reader will
