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same is to be performed, to be particularly described and ascertained in and by the following statement :— The object of my invention is to provide a cheap and effective apparatus for recovering gold which has been precipitated from its solution upon charcoal or similar substances. The processes that have hitherto been employed have been both slow and wasteful, and, owing to the minuteness of the gold particles to be recovered, unavoidable losses of that metal have always arisen. But with my improved furnace and apparatus a much quicker destruction or burning of the charcoal is admitted, whilst it has the distinct advantage of recovering the whole of the gold. My invention consists of a circular or other shaped outer shell situated over a series of furnace-bars. Inside the outer shell is an inner one, into the top of which the auriferous material to be treated is placed. The fire already kindled causes fumes to be liberated from the charcoal, which fumes are drawn into the space (annular or otherwise) which exists between the inner and outer shell. From the top of this space they are drawn into a precipitating-box, in which they are robbed of all the particles that may be held in suspension. But in order that my invention may be better understood I will now refer to the accompanying sheet of drawings, which are to be taken as part of this specification, and read herewith. Fig. 1 represents a sectional elevation of my invention, the arrows showing the course of the ingoing air and of the outgoing fumes generated. Fig. 2 represents a plan of the same. Similar letters of reference indicate similar or corresponding parts where they occur in the several views. On reference to the drawings it will be seen that Ais the outer shell, near the bottom of which are the furnace-bars B. These latter are placed at the top of the lower chamber C, and may be removed or replaced either from the top of the outer shell or from a door in the side of the same. This lower chamber or ash-pit is provided with a draw-off or drain-tap and a door D, through which door, after or before the water is drawn off, all auriferous accumulations or sludges are removed. The chamber C is partially filled with water, the height of which is regulated preferably by a ball-operated tap E, situated within an auxiliary water-chamber E. Resting upon the top of A, or secured in any other way, is the inner shell G. This, which is open at both ends, may be either taper or parallel or longer or shorter than shown. As will be seen, the bottom end does not reach the fire-bars, but stands some distance above them. Into the top of G, which is generally uncovered, the auriferous material is fed wet, as it comes from the fillers, when it falls upon the fire-bars upon which a fire has been previously kindled. The charcoal is fed into G until it is flush with the top of the same, and as it is consumed the supply is replenished. Air is admitted beneath the furnace-bars by the airinlet holes J, situated in the ash-pit portion, the area of which holes may be adjusted in any well-known way. The gases or fumes arising from combustion, instead of passing upwards and outwards through the top of G, are drawn into the covered space between A and G, which may be provided with a spiral circulating web or webs H. At the top of Ais a pipe I leading the fumes into the inlet end of a precipitating-box X containing water. This box is divided above the water-line into an inlet and an outlet end by a bulkhead or baffle-plate L, which descends from the top and is partially immersed in the water. The height of this bulkhead, which may be of any shape or shapes, is regulated in any well-known way, either from the interior or the exterior of the box. Beneath the surface of the water and at any predetermined height, and extending from one end of the box to the other, is a gauze or grating M. Beneath L one or more similar gratings N extend to the bottom of the box. Above the water on the outlet end is a discharge-pipe 0, on which is an ejector operated by water, exhaust or other steam, compressed air, or a fan ; or a natural draught may be induced by a chimney. At the bottom of the precipitating-box, which, to assist the wash of the water, is preferably made with a concave bottom as shown, is a longitudinal or other slot P. In this the auriferous or other deposits gradually fall and gather in a receiver Q, from which they can be removed for treatment by a sluice valve, cock, or other means without arresting the progress of operations. In the side of the tank and in any convenient position may be situated an observation-window R. There may also be a gauge-glass if necessary ; and on the top of the box, and attached to the removable covers thereon, one or more water-inlet or flushing cocks S. To the said box may be connected, as to the ash-pit chamber, an auxiliary water-chamber, whereby the water in the box may be maintained at a uniform level. The cycle of operations is as follows: A fire having been kindled on the bars and the ash-pit being partially fitted with water, the auriferous material is charged into the inner shell. The air, entering the air-inlet holes, passes with the water-vapour generated from the water in the ash-pit through the fire-bars. As the air and vapour emerge from above the fire they enter the space between the two shells, and pass out of the same by the pipe leading to the inlet end of the precipitating-box. The fumeladen air then enters the water with which the latter has been first charged, and, passing through the horizontal and vertical gratings, has thereby arrested all the particles that it was carrying away in suspension. These are precipitated in the form of a deposit or sludge in the bottom of the box, and are removed from the receiver and treated as required. Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is,— 1. The improved furnace for recovering gold from charcoal or similar substances, consisting of the combination of an outer shell as A, with an inner shell as G, both of which are situated above a series of fire-bars, all as and for the purposes hereinbefore described and as illustrated in the drawings. 2. The improved furnace for recovering gold from charcoal or similar substances, consisting of the combination of an outer shell as A, having air-inlet holes on its bottom, an inner shell as G, having a spiral web as H around its circumference, both shells being above fire-bars as B, a closed

25—C. 3.