Large arrows tipped with strong paper cases, such as are made for rockets, only choked at the bottom, become most formidable projectiles. The cases are partly filled with powder, a wad, with a hole in it, is rammed down on the charge, a quill is put in the hole, about thirty buck shot are deposited round the quill, which is filled with meal powder. The case and quill head are then capped with paper which has been soaked in dissolved gunpowder or nitre. Arrows thus made are to be fired from powerful hand-bows, after the match has been lighted. In the true rocket arrow the touchpaper is ignited just before the arrow is fixed in the bow, and it is shot just before the fire reaches the composition; the combustion then aids the flight rather than retards it. The head is strongly barbed, so that it may not easily be drawn from thatched roofs, &c.; the Chinese and Indian tribes often use these.
It sometimes happens that the hunter or explorer has, like many members of the Algerian, Tartar, and Mongolian tribes, to turn gunpowder manufacturer. To make gunpowder three ingredients are requisite: viz., saltpetre (nitrate of potash), sulphur, and charcoal. The two former ingredients should form a part of the equipment of an expedition (see “Farrier’s Stores,” [p. 84]). Still, where such stores are not carried, sulphur and saltpetre are usually to be obtained, more or less pure, from the natives of all but the most unfrequented and isolated countries. The saltpetre will require recrystallisation, which is carried out as follows: Take equal quantities, by measure, of the saltpetre and boiling water, stir them well about with a stick until all the lumps are thoroughly dissolved; strain the resulting fluid through a coarse cloth in order to get rid of sticks, chips, and stones, and set it aside to crystallise; when the process is complete drain the water from the crystals, set them to dry on a skin or a cloth. The sulphur, if in lumps as imported, will require purification by melting. This operation must be conducted over a very slow fire, and immediately the mass becomes liquid in the pot it should be put to stand for a few minutes in hot wood ashes in order that impurities may settle to the bottom. The neck of the vessel may then be held fast in a twisted stick, and the contents poured dexterously out into a convenient mould until the sediment at the bottom, which is useless, is left. Flour of sulphur will not require this treatment. The charcoal (see “Charcoal Burning,” [p. 267]) should, for gunpowder making, be prepared from some light, clean-grained wood. In this country willow, withy, alder, hazel, linden, &c., are held in high esteem for the purpose; but in wild countries the nearest approach to these within reach should be obtained. The three ingredients must be first separately ground, either in a native quern or stone handmill, between two conveniently-formed stones, or in an extempore pestle and mortar, until reduced to perfect powder, quite free from lumps or grit. The three powders are to be now weighed out carefully in the following proportions: One part sulphur, one part charcoal, and six parts saltpetre. Mix these on a skin pegged out on the ground, and rub the mixture together with the palms of the hands until most intimately and thoroughly blended; then, with an empty percussion-cap box or drinking cup, measure your mixture, and for every ten cups or boxes of powder put down a stone or make a mark, and for every mark put aside a cup full of warm water, so that you have just one-tenth of fluid. This you sprinkle with a bunch of feathers or grass, a little at a time, on the powders, until, by constant and persistent working and kneading, a smooth homogeneous paste is formed. Two well-selected stones much facilitate this stage of the process; one should be large and flat, the other water-rounded and oval; in fact, a water-worn pebble of about 2lb. weight. By sitting on the stretched skin with the flat stone between the legs, the water and sprinkler at the side, and the pebble between the hands, the paste can be effectually worked up; and it is well to bear in mind that on the perfect homogeneity of this paste depends, in great measure, the quality of the gunpowder.
The paste—or devil as it is sometimes called—being thoroughly elaborated, make square flat cakes of it 6in. square and 2in. thick, and wrap them compactly up in cotton cloth or old sheeting four or five times doubled; then stitch up a stout hide bag just large enough to contain all your cakes and their coverings when built in compactly one on the other, and sew up the opening; then, with a chisel, scoop out a cavity in the end of a log just deep enough to half bury your case of cakes; then, with the aid of a neighbouring tree, and a few suitable pieces of wood, which are easily fashioned with the axe, prepare such a press as is shown in the above illustration. The weight should be increased gradually, and the pressure intensified until the cakes are pressed into compact masses. The coverings are now to be removed, and then the process of coming begins, and the help of a corning sieve is required. This is made as follows: Make a wide stout hoop of any pliant wood, and over one of its edges stretch a head of parchment, like that of a banjo, nail or lace it on wet, and when dry it will become perfectly tight, like the head of a tambourine. Now, take a very small-sized key, file off the wards and bow, sharpen the lower edges round the tube with the file until it is converted into a sharp hollow punch. Turn your tambourine upside down on a smooth-faced log of suitable size, and, with a small hammer and your little punch, proceed to perforate the parchment until the head is covered with small round holes. Now fashion from any dry, hard, heavy wood a flat disc 1½in. thick and 4½in. in diameter; this, with the broken cake, is put in the sieve and rattled about forward and back until the small broken granular fragments are in numbers forced through the holes in the parchment, and fall on the skin stretched to receive them. It will be found that among the grains thus formed there will be a certain quantity of fine dust; this can be separated by sweeping the grains over a sloping board on which flannel has been stretched, the grains pass on, the dust remains amongst the fibres of the wool, and can be collected to work up again. The granules can now be placed in a little wooden box and shaken about until rubbed smooth against each other. To finish them off it is well to place a large sheet of iron, copper, tin, or any other metal over a pot of boiling-hot water, throw the now all-but-finished gunpowder on the plate and stir it about until completely dry. A clean frying-pan is by no means a bad instrument for powder drying; take care that it is only placed on hot water, and not subjected to fire heat, or a blow-up will probably follow. Too much caution cannot be used after the powder has been subjected to the granulating process; before that there is little to fear, after it a great deal.
SEARCHING FOR GOLD.
Geology for travellers.