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.

[Sketch].

Substitutes for glass.—­These are waxed or oiled paper or cloth, bladder, fish-membranes, talc, and horn. (See “Horn.”)

SLEEPING-BAGS.

Sleeping-bags.—­Knapsack Bags.—­These have been used for the last twenty-five years by the French ‘douaniers’, who watch the mountain-passes of the Pyrenean frontier.  The bags are made of sheepskin, with the wool inside.  When not in use they are folded up and buckled with five buckles into the shape of a somewhat bulky knapsack (p. 152), which the recent occupant may shoulder and walk away with.

The accompanying sketches are drawn to scale.  They were made from the sleeping-bag belonging to a man 5 feet 6 inches in height; the scale should therefore be lengthened for a taller person, but the breadth seems ample.  Its weight was exactly seven pounds.  The douaniers post themselves on watch more or less immersed in these bags.  They lie out in wet and snow, and find them impervious to both.  When they sleep, they get quite inside them, stuff their cloaks between their throats and the bag, and let its flap cover their faces.  It is easy enough for them to extricate themselves; they can do so almost