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half as large again as the finer. Some of the ore now being put into a strainer of wire gauze, considerably coarser than either of these two, and a tub being filled with water, and a receptacle placed at the bottom to catch the ore as it falls, let the water be set in gentle rotary motion, and the strainer held at some point midway between the centre and the edge, at the surface of the water, so as to scatter the ore to the bottom, it will be seen at once that the action of the water in motion is to spread the ore out in a fan-shaped shower as it falls. The fact is, indeed, that the lighter particles, taking a little longer to fall than the heavier ones, are carried round by the current to a greater distance, and consequently are deposited further away from the strainer than the heavier particles. The results of this simple experiment, if carefully conducted, are really striking, and look at first sight like magic. "In the machine, as now finally worked out and patented in the leading colonies of Australia by Mr. George Sutherland, M.A., many points have required attention besides the primary principle thus illustrated on a small scale. Laboratory experiments are one thing, and work on a large scale and of a commercially profitable character is quite another matter. The final result, however, is that a machine about 10ft. in diameter is now capable of putting through 50 tons per day. The ore is fed on to a distributor near the centre, this distributor having eight feeding arms, of which the plan and section are shown in the diagrams. Bapid vibration is imparted to the distributor by means of a ratchet wheel, and the ore falls through a bottom of wire gauze inclined away from the direction taken by the water, so as'to give a larger distributing surface, and yet to make the section of the angle made by the ore, as it leaves the arm, as small as possible. Circular motion is imparted to the water by means of horizontal paddles, of which only the ends are to be seen in the illustration. In the working of the apparatus each arm gives out its stream of ore, which falls on a false bottom consisting of perforated metal, and thence falls immediately into compartments set below this false bottom, and intended to receive the first- and second-grade concentrates and the tailings respectively. The whole arrangements of the distributors and the receptacles are set upon a central pivot, and can be readily turned round, as in a railway turntable, so that, on the compartments being filled with ore, they can be pulled round, each set in turn, till they come over a track, which slopes down into the water, for the reception of trucks. Into these trucks the ore is tipped, still occupying separate compartments in the truck which correspond to those in the first receptacles. The trucks are withdrawn from time to time, and emptied as required. Preliminary sizing or classification, prior to treatment, is an essential of good concentration under any system whatever, and for this purpose the well-tried plan of a revolving cylindrical sieve or 'trommel' is preferred. The whole of the operations, however, are performed by means of gravitation, and the necessity for handling the ore is reduced to a minimum. " Over twenty widely-different ores and tailings have been treated by the machine during the past year, and four distinct uses have been determined as within its sphere of work, these being— First, the extraction of mercury—amalgam from gold-tailings : In one case where tailings were tested it was found that, these being highly odidized pyritous stuff containing antimony, the mercury had been held most stubbornly. The machine brought it out remarkably well, the first grade being practically pure amalgam, and the proportion saved being l}lb. per ton of tailings. Secondly, the saving of auriferous pyrites : Several samples have been treated, with the most successful results, Sutherland's machine being used for quickly and economically throwing out about nine-tenths of the dead sand, and the final cleaning up of the second grade being left to the vanner, either the Frue or the Luhrig machine being applicable. It was found that the tailings thrown out by the machine were fully as clean of pyrites as those rejected by the Frue vanners on one of the best-managed mines in Australia. In the trials of stuff from this mine 100 parts of tailings from the stamps were reduced by the machine to thirteen parts of medium concentrates, and these were proved chemically and mechanically to contain 89 per cent, of the total pyrites in the ore. Thirdly, the concentration of auriferous copper, antimony, and other ores into a form suitable for smelting: In this class of work it was found that stuff only going 2dwt. or 3dwt. to the ton could be worked up very cheaply, so that the first grade would contain from 2oz. to 3oz. Fourthly, the very cheap grading of low-grade silver, lead, tin, or copper ores : Trials upon ores from Broken Hill and other localities show that the new machine, while using a very small quantity of water, does really more accurate work than any of the jiggers or vanners hitherto put into use. The machine is in itself practically a self-acting settling-pit, and hence it effects a great economy in water. "The inventor of this new system, Mr. George Sutherland, M.A., has hitherto come before the public as an inventor of processes connected with printing and photography which have been in successful use in England and Australasia during the past seven years, and we recently printed a reference to articles by him in Nature, referring to the deposition of gold and silver. During the past three years he has devoted his attention to the great problem of utilising low-grade ores by means of concentration; and last July he demonstrated the main principles of his new machine before the Victorian Boyal Commission on gold-mining, when it was generally acknowledged by experts that something really new and of great promise to the mining industry had been brought to light by Mr. Sutherland's labours. Invitations to send samples to the Melbourne address of the inventor at Lytton Street, Carlton, and to his Adelaide address, at Angas Street, were freely responded to, and to the courtesy of directors and managers Mr. Sutherland ascribes much of his success in ascertaining the exact field of usefulness before the new machine. The apparatus being so simple and inexpensive, it is intended that those wishing to use it will be supplied with lithographic plans of all but a few small details, which will be sent ready made, and a small fixed royalty will be charged for each year of successful working. This plan has been adopted partly because the inventor does not wish to enter into competition as a maker of machines, but to rely as far as possible upon the services of those who have already made their mark as makers of mineral-saving machinery." Mr. Sutherland also kindly sent the following particulars in reference to the machine. Plans showing the appliances are hereto annexed (see plan next page):—