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Newbery-Vautin plant, and which is found to be of no service by the United Pyrites Company. They do not use it, as they find it of no advantage to the process of chlorination. The only improvement in this plant from that of the Mears process, which Mr. Rothwell described as used in North .Carolina in 1873, is a vacuum-pump to extract the liquor from the sand after the chlorinating-barrel is~emptied, which was not referred to by Mr. Eothwell; but it does not seem to be a new process. The pyrites is brought to the United Pyrites Company's works from the several crushingbatteries on the field, also from Dalesford and Stawell, to be treated. It is operated on, chlorinated, and the gold extracted at a cost of £3 per ton. The company also purchase pyrites by assay, and treat it on their own account. The process is as follows : — The pyrites is first roasted in reverberatory furnaces the same as for the amalgamating process, and then taken to the chlorinating plant, which consists of a revolving cylinder or barrel made of iron, and lined with sheet-lead about -Jin. in thickness. The iron cylinder is about 4ft. 6in. in diameter, with flanges at both ends. The lead is made in a cylinder and slipped inside the irpn cylinder. The ends are then hammered down against the flanges of the iron cylinder, thus forming a lead flange. The ends of the cylinders are covered with a sheet of lead and bolted on to the flanges of the cylinder. There is a hole on one side in the centre, and the lead is hammered up to cover the edges of this opening in the iron, so that none of the liquor in the cylinder touches any part of the iron. Directly under this revolving cylinder there is a leaching-pan also lined with sheet-lead ; but a wooden vat coated with asphaltum would answer the same purpose. There is a false bottom in this pan about lin. above the main bottom, with perforated holes. On the top of the false bottom there is a filter-bed of quartz and coarse sand about sin. in thickness. This is covered on the top with a very coarse cloth, the object being to preserve the filter-bed from being damaged when running out the waste sand. There are also two liquor-tanks, each about sft. in height and 4ft. 6in. in diameter. Besides these there are a number of earthenware jars filled with charcoal, through which the liquor filters, the gold being deposited on the charcoal. The revolving cylinder is charged first by putting in water for about lft. in depth and about 341b. of sulphuric acid. The ore is then put in—about 25cwt. in one charge—and to this is added about 301b. of chloride of lime ; but the quantity of sulphuric acid and chloride of lime depends entirely on the quantity and chemical properties of the ore to be treated—some ores require a larger quantity than others. The cover, having an indiarubber joint, is now screwed on in the same manner as on a gas-retort, and the cylinder set in motion. There is a valve attached to the cylinder to admit of air being forced in ; but the person in charge of the work at the time of my visit informed me that they had disregarded forcing in air, as they found it of no advantage in the process of chlorination. The amount of gases generated by the mixture of sulphuric acid, would be considerable—probably about from 251b. to 801b. to the square inch—that is, if the ore has been perfectly roasted before being operated on, but, if not, the pressure inside the cylinder would be greater. The revolving cylinder is driven by a belt and pulley on an intermediate shaft from the engine. This shaft also works two pumps—one for air if required, and another for creating a vacuum. The cylinder is kept revolving at a speed of about seven revolutions per minute for about three hours, more or less, according to the fineness or coarseness of the gold, when the whole of the gold is in solution. The cylinder is now stopped and the cover removed. Afterwards the cylinder is again set in motion, and the ore and liquor falls into the pan or vat with the false bottom already described, and when empty another charge is made, and the same operation gone through. A vacuum-pump is connected with the main bottom of the pan or vat already described, and the liquor is drawn through the sand and goes into the other two receiving-vats. Water is added, and the liquor tested from time to time as it comes from the leaching pan or vat, and when, by adding sulphate of iron in the test, the liquor remains perfectly clear, this operation ceases. After all the gold-liquor has been removed the sand is cleaned out ready for the next charge. In the vats which contain the liquor there are placed coils of perforated leaden pipes, which are attached to the air-pump, and the action of this pump forces out any gases in the liquor. The liquor-vats stand about 2ft. above the first row of earthenware jars which contain the charcoal. There are three rows of these jars, one below another, so that the liquor filtering through one passes through the one below it. These jars are of different diameter, but it can be said that the liquor filters through a column of charcoal about 4ft. in height. As the solution passes through the charcoal the gold is precipitated in a metallic state. The charcoal is then burned, and the ash mixed with borax and melted. The water in passing through the charcoal is tested from time to time to ascertain if the waste liquor contains any gold. In the pamphlet published by Messrs. Newbery and Vautin some time ago the cost of this process was to be about 12s. per ton; but this statement is not borne out by those that are using it. Mr. S. McGowan, the legal manager of the company, assured me that the cost of treatment is as much as with the old chlorination-vats, but that the Newbery-Vautin process gave a higher percentage of gold. It is estimated that an average of 93 per cent, of the gold is obtained by this process. Annexed is a plan of this plant at the United Pyrites Company's works at Sandhurst. (See Figs. 25 and 26.) The Newbery-Vautin process is, however, too costly to deal with low-grade ores. There are chlorination-works erected at the Butters Ore-milling Works, Kennett, on the banks of the Sacramento Eiver, on the line of the California and Oregon Eailroad, and now in operation, and if a description of the results of these works is to be depended on they will supply a want which is greatly needed in the treatment of low-grade ores. The following description is taken from the Mining and Scientific Press of S§,n Francisco : — "The works consist of a roasting-house containing a reverberatory furnace 43ft. outside and 12ft. Bin. wide, containing three hearths each 10ft. square, a dust-chamber, and two alternate cool-ing-pits for chlorination on cooling-floor. The lixiviation-house contains two ore-tanks 14ft. in 4—C. 3.