'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
date