In the beautiful valley of the Kowie River, a few miles below Grahamstown, we saw a rather ingenious application of wind power to a horizontal wheel. The principle will be best shown by calling to the reader’s memory the well known nautical toy which consists of four or more cutters, or fore and aft rigged vessels, sailing in a circle on a mast-head or flag-staff. In the fore and aft sails the foremost leach, or edge, is attached by rings, or otherwise, to the mast or stay of the respective sail, and is stretched tight, while the after leach is left more or less free, according as the sheet is hauled in or eased off. In consequence of this when the vessel is before the wind the sails fill, but as their surface catches it obliquely they do not exert their full force till the vessel receives the wind upon her quarter. When the wind is “a-beam,” or blowing across her at right angles, the sails are still helping her forward, and continue to do so, even when her head comes up so near as just not to shake the wind out of them. When this happens, the sails lose their power, as they present only their foremost edge to the wind, and not a broad surface like those of a square-rigged ship when she is taken aback. (We will therefore suppose four cutters, a, b, c, d.) The cutter a is before the wind, b has the wind somewhat on the quarter, while c, having “come up” several points, is now nearly head to wind with her sails shaking, and d has taken the wind on the other tack. Thus, there are always three vessels whose sails are helping them round in one direction, while the fourth, for the moment that she is in the “wind’s eye,” is powerless to resist them.
This power can be applied to a large horizontal wheel. There should be two wheels, one 18in. or 2ft. above the other; they are made as light as possible, and each has a smaller rim or felloe, say 18in., within the other. The sails are in this instance flat boards, with a dowel left on each end for a hinge. These dowels work in holes in the upper and lower spokes, midway between the inner and outer felloes. It will be seen that the sails marked will receive the wind on one side until, coming so far before it that they “jibe,” they assume the position of those which receive it on the other. When they come up to the wind on the other side the wheel they present their hinged edge to the wind, and shift like the sails of cutter c, but without shaking. The best angle for them to make is 22½° on either side the central line, and this is also the angle at which the sails of a windmill should present their surfaces.
Well sinking.
The explorer, or settler, will not unfrequently have to sink wells for the obtainment of water for himself and his animals. It will often happen that Nature has commenced the formation of a well, which merely requires the labours of man to complete. The crowbar and pick will, in such cases, very quickly enable the traveller to deepen it sufficiently to meet his temporary needs. Where a long-continued residence is intended, and a regular and continuous supply of water is required, apart from that obtained from rivers or lakes, wells of greater or less depth, according to the nature of the ground and water supply, must be undertaken.
The Indians manage to construct walled wells of great depth in loose sandy soil in the following ingenious manner: They first mark a circle, the size of the intended well, on the earth. They then dig a groove, or trench, of the width of the intended thickness of the lining wall of the well, much as our masons sink a foundation for a house. They now proceed to build a circle of masonry in the groove, and carry it up to a few feet in height above the surface. Other Indians now get inside the wall, and, with short-handled hoes and fire-hardened sticks, dig away the sand from beneath the foundation of the wall round the entire circle. As the sand is loosened and dug out, it is taken up in cane baskets and thrown outside. As the wall sinks into the earth by being undermined, it is constantly added to by building above until the required depth is reached.
The Chinese sink very narrow and deep wells by the use of a kind of jumper, or boring bit. This is hung suspended from the end of a long bamboo spring beam, which is constantly worked up and down, thus causing the bit to constantly drop and pick, so to speak, on one spot. The bit is hollow, and when it becomes full of sludge produced by its incessant tapping, it is withdrawn from the hole, cleared out, and entered again. A little water added from time to time much assists the operation, and tends to keep the bit from becoming heated. As it will be seen this method, although very useful as a makeshift, is tedious to a degree.
Much fear was entertained at the commencement of the Abyssinian war that there would be a great scarcity of water in consequence of the comparatively limited number of wells and indifferent quality of the water to be found in that portion of the country over which our troops had to march shortly after their arrival; and there is little doubt but that serious inconvenience, if no worse, would have been experienced, had not a contrivance, known as the “American tube well-borer,” the invention of Mr. Norton, been brought to the notice of the Government authorities. The wells formed by these deeply-penetrating sets of tubes were found to supply water freely and expeditiously in that country. How far the perforated end of the tube would be effective, if driven through clay, we have had no means of ascertaining; but we are of opinion that for reaching deeply-buried water-yielding deposits of ordinary character the tube-borer will be found most valuable. Its action is simplicity itself.