Paper referred to in the preceding Letter.

The carpentry of the roof being formed with its proper descents, is, in the first place, sheeted or covered with deals, nailed horizontally upon the rafters, after the same manner as when intended to be covered with lead. The sheets of the copper for this covering are two feet by four, and for covering the slopes of the roof are cast so thin, as to weigh eight or nine pounds, and for covering the flats or gutters, ten or eleven pounds each, or about one pound, or a pound and a quarter, to the superficial foot.

A string of strong cartridge paper (over-lapping a little at its joints) is regularly tacked down upon the sheeting, under the copper covering, as the work proceeds from eaves to ridge. It prevents the jingling sound of hail or rain falling upon the roof, and answers another purpose to be mentioned by-and-by.

In order to shew the regular process of laying down the roof, we must begin with fastening two sheets together lengthwise. The edges of two sheets are laid down so as to lap or cover each other an inch, and a slip of the same copper, about three and a half inches broad, called the reeve, is introduced between them. Four oblong holes, or slits, are then cut or punched through the whole, and they are fastened or riveted together by copper nails, with small round shanks and flat heads. Indents are then cut 1¾ inch deep upon the seam at top and bottom. The right hand sheet and the reeve are then folded back to the left. The reeve is then folded to the right, and the sheets being laid on the roof in their place, it is nailed down to the sheeting with flat-headed short copper nails. The right hand sheet is then folded over the reeve to the right, and the whole beat down flat upon the cartridge paper covering the sheeting, and thus they are fastened and laid in their places, by nailing down the reeve only; and by reason of the oblong holes through them and the reeve, have a little liberty to expand or contract with the heat and cold, without raising themselves up from the sheeting, or tearing themselves or the fastening to pieces. Two other sheets are then fixed together, according to the first and second operations above, and their seam, with the reeve, introduced under the upper ends of the seam of the former, so as to cover down about two inches upon the upper ends of the former sheets: and so far the cartridge paper is allowed to cover the two first sheets. This edge of the paper is dipped in oil, or in turpentine, so far before its application, and thus a body between the sheets is formed impenetrable to wet, and the reeve belonging to the two last sheets is nailed down to the sheeting as before, and the left hand sheet is turned down to the right. Four sheets are now laid down, with the seam or joint rising to the ridge; and thus the work is continued, both vertically and horizontally, till the roof be covered, the sides and ends of each sheet being alternately each way, undermost and uppermost.

The price for copper, nails, and workmanship, runs at about eight pounds ten shillings per hundred weight, or two shillings and three-pence per foot, superficial, exclusive of the lappings; and about two shillings and eight-pence per foot upon the whole; which is rather above half as much more as the price of doing it well with lead.

TO PETER COLLINSON, ESQ. AT LONDON.