Tente d'abri.--The French, "tente d'abri" has not, so far as I know, been adopted by travellers: it seems hardly suitable, except for soldiers. Each man carried a square of canvas (fig. 1), with buttons and button-holes all round it, by which it can be doubly attached to other similar squares of canvas, and thus, from several separate pieces, one large cloth can be made. The square carried by the French soldier measures 5 feet 4 1/2 inches in the side, reckoning along the buttons; of these there are nine along each edge, including the corner ones. Each soldier has also to carry a tent-staff, or else a proportion of the pegs and cord. When six men club together they proceed as follows:--Three tent-sticks are fixed into the ground, whose tops are notched; a light cord is then passed round their tops, and fastened into the ground with a peg at each eng (fig. 2). Two sheets, A and B, are buttoned together and thrown over the cord, and then two other sheets, C and D; and C is buttoned to A, and D to B (fig. 3). Lastly another sheet is thrown over each of the slanting cords, the one buttoned to A and B, and the other to C and D; and thus a sort of dog-kennel is formed, in which six men--the bearers of the six pieces of canvas--sleep. The sides of the tent are of course pegged to the ground. There are many modifications in the way of pitching these tents. Should the sticks be wanting, faggots or muskets can be used in their place.
Tent of Mosquito-netting.--I have been informed of a sportsman in Ceylon, who took with him into the woods a cot with mosquito-curtains, as a protection not only against insects, but against malaria. He also had a blanket rolled at his feet: at 3 in the morning, when the chill arose in the woods, he pulled his blanket over him.
Pitching a Tent.--It is quite an art, so to pitch a tent as to let in or exclude the air, to take advantage of sun and shade, etc. etc. Every available cloth or sheet may be pressed into service, to make awnings and screens, as we see among the gipsies. There is a great deal of character shown in each different person's encampment. A tent should never be pitched in a slovenly way: it is so far more roomy, secure and pretty, when tightly stretched out, that no pains should be spared in drilling the men to do it well. I like to use a piece of string, marked with knots, by which I can measure the exact places in which the tent-pegs should be struck, for the eye is a deceitful guide in estimating squareness. (See "Squaring.") It is wonderful how men will bungle with a tent, when they are not properly drilled to pitch it.
To secure Tent-ropes.--When the soil is loose, scrape away the surface sand, before driving the tent-pegs. Loose mould is made more tenacious by pouring water upon it. When one peg is insufficient, it may be backed by another. (See fig.) The outermost peg must be altogether buried in the earth. Heavy saddle-bags are often of use to secure the tent-ropes; and, in rocky ground, heavy piles of stones may be made to answer the same purpose. The tent-ropes may also be knotted to a cloth, on which stones are afterwards piled.
"Dateram" is, as the late Dr. Barth, informed me, the Bornu name for a most excellent African contrivance, used in some parts of the Sahara desert, by means of which tent-ropes may be secured, or horses picketed in sand of the driest description, as in that of a sand dune, whence a tent-peg would be drawn out by a strain so slight as to be almost imperceptible. I have made many experiments upon it, and find its efficiency to be truly wonderful. The plan is to tie to the end of the tent-rope, a small object of any description, by its middle, as a short stick, a stone, a bundle of twigs, or a bag of sand; and to bury it from 1 to 2 feet in the loose sand. It will be found, if it has been buried 1 foot deep, that a strain equal to about 50 lbs. weight, is necessary to draw it up; if 1 1/2 feet deep, that a much more considerable strain is necessary; and that, if 2 feet deep, it is quite impossible for a single man to pull it up. In the following theoretical case, the resistance would be as the cube of the depth; but in sand or shingle, the increase is less rapid. It varies under different circumstances; but it is no exaggeration to estimate its increase as seldom less than as the square of the depth. The theoretical case of which I spoke, is this:--Let x be part of a layer of shingle of wide extent: the shingle is supposed to consist of smooth hard spherical balls, all of the same size. Let s be a dáterám buried in x; and T the string to which it is tied. Now, on considering fig. 2, where a series of balls are drawn on a larger scale and on a plane surface, it is clear that the ball A cannot move in any degree to the right or the left without disturbing the entire layer of balls on the same plane as itself: its only possible movement is vertically upwards. In this case, it disturbs B1 and B2. These, for the same reason as A, can only move vertically upwards, and, in doing so, they must disturb the three balls above them, and so on. Consequently, the uplifting of a single ball in fig. 2, necessitates the uplifting of the triangle of balls of which it forms the apex; and it obviously follows from the same principle, that the uplifting of S, in the depth of X, in fig. 1, necessitates the uplifting of a cone of balls whose apex is at S. But the weight of a cone is as the cube of its height and, therefore, the resistance to the uplifting of the dáterám, is as the cube of the depth at which it has been buried. In practice, the grains of sand are capable of a small but variable amount of lateral displacement, which gives relief to the movement of sand caused by the dateram, for we may observe the surface of the ground to work very irregularly, although extensively, when the dáterám begins to stir. On the other hand, the friction of the grains of sand tends to increase the difficulty of movement. The arrangement shown in the diagram, of a spring weighing-machine tied to the end of a lever, is that which I have used in testing the strain the dateram will resist, under different circumstances. The size of the dateram is not of much importance, it would be of still less importance in the theoretical case. Anything that is more than 4 inches long seems to answer. The plan succeeds in a dry soil of any description, whether it be shingly beach or sand.
Bushing a Tent means the burying of bushes in the soil so far as to leave only their cut ends above the ground, to which a corresponding number of tent-ropes are tied.