Tarpaulings are very suitable for roofs. Those made after the method used by sailors are much superior to others in softness and durability. The plan is as follows:--As soon as the canvas has been sewn together, it is thoroughly wetted with sea-water; and, while still wet, it is smeared over on one of its sides with tar and grease, boiled together--about two parts tar and one of grease. After being hung up till it is dry, it is turned; and the other side, being a second time well wetted, is at once painted over with the tar and grease, just as the first side had been before. The sailors say that "the tar dries in, as the water dries out;" a saying which I confess I cannot understand.
Other Materials.--I will merely mention these by name, for they require no explanation. They are fascines or faggots; bricks, sun-dried or baked in the oven; turf; stones; and bags or mats, filled with sand or shingle.
Whitewash is lime and water. Lime is made by burning limestone, chalk, shells, or coral in a simple furnace.
Roofs.--Thatching.--After the framework of the roof has been made, the thatcher begins at the bottom, and ties a row of bundles of straw, side by side, on to the framework. Then he begins a second row, allowing the ends of the bundles composing it to overlap the heads of those in the first row.
Wood-shingles are tile-shaped slices of wood, easily cut from fir-trees. They are used for roofing, on the same principle as tiles or slates.
Floors.--Concrete for floors, is made of eight parts large pebbles, four parts river-sand, and one part lime (to make lime, see "Whitewash"). Cow-dung and ashes make a hard, dry, and clean floor; such as is used for a threshing-floor. Ox blood and fine clay kneaded together are excellent. Both these latter compositions are in use in all hot dry countries.
Windows.--A window, or rather a hole in the wall, may be rudely shuttered by a stick run through loops made out of wisps of grass. In hot weather, the windows of the hutmay be loosely stuffed with grass, which, when watered, makes the hut cooler.
Glass, to cut.--Glass cannot be cut with any certainty, without a diamond; but it may be shaped and reduced to any size by gradually chipping, or rather biting, away at its edges with a key, if the slit between the wards of the key be just large enough to admit the pane of glass easily.
