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until another charge is ready to be run off from the combination-pan. The slime is gradually drawn off from the settler, and the quicksilver and amalgam collects in the bottom of the pan, and is drawn ofFinto a canvas straining-bag, where the amalgam is finally collected. In addition to these appliances there is a revolving Howell roasting-furnace ; but they were not using this at the time of my visit. Mr. Russell informed me that they found no benefit in chloridizing the ore before amalgamation ; at the same time, he admitted he was only saving about 60 per cent, of the silver in the ore. He was erecting a Frue vanner to try experiments with concentrating the ore. The operations at this company's works have consisted in nothing but experimenting as to the best class of machinery to adopt. For the past twelve months machinery has been erected and pulled to pieces again and again, and another class of machinery tried. Explosives have even been used to break up some of the original plant, without any other apparent reason than to prevent its remaining a memento of the experiments. There is, however, a good plant now erected, and it is to be hoped that there will be an abundance of payable ore to refund the shareholders for the large outlay and money spent in foolish blundering, which would not have been tolerated had it belonged to local proprietors; but, unfortunately, the money spent is foreign capital, and unless the mine possesses some rich ore to recoup the outlay it will be the means of retarding the introduction of capital into the colony for mining ventures. The whole of the machinery was at the time of my visit driven by a horizontal under-type semi-portable steam-engine; but the company were erecting two Pelton water-wheels of 7ft. diameter and 15in. face, and intended to utilise the water from the Ohinemuri River as a motivepower. An underground tail-race has been constructed from the Ohinemuri River to the batteryhouse, to carry off the waste water from the Pelton wheels. A large shaft or paddock is sunk at the head of the tail-race and strongly timbered. In the bottom of this shaft or paddock the wheels are erected, where they are under an available head of water of 50ft., which will give about four and a half effective horse-power for every sluice-head of water they use on the wheels. A dam has been constructed in the Ohinemuri River, and also another dam has been constructed in one of the branch creeks, as a supplementary supply. The water-race from the main dam to the battery is about 212 chains in length, and the dimensions of the ditch are, 3ft. 6in. on the bottom, 9ft. across the top, and 2ft. 9in. in depth. Assuming that it is capable of conveying water to the depth of 2ft. 6in., this would be equal to about twenty sluice-heads ; the fall or gradient of the ditch being 1 in 2,000. A pumping and winding shaft is sunk to a depth of about 130 ft., and all necessary gear erected, but no workings had been carried on from the shaft at the time of my visit. There were eight men employed in breaking out ore from the adit-level, and twelve men employed in the construction or completion of the underground tail-race, as well as a number of mechanics engaged in the erection of the plant. A large quantity of ore was on the surface ready for treatment. Since writing the above description of this plant, Mr. J, W. Walker, at the request of the Inspector of Mines, Thames, supplied him with a full description of the reduction plant and goldsaving appliances used by the company of which he is manager; and, as his remarks thereon are interesting to those engaged in the treatment of auriferous and argentiferous ores, and worthy of notice, the following is his reply to Mr. Wilson's letter: — " Sm, — " Waihi Gold-mining Company, Bth April, 1890. " Agreeable to your request dated 21st March, I send the following description of our reduciion and gold-saving plant:— " Engines. —One semi-portable compound forty-horse power; and one horizontal with Cornish boiler—diameter of cylinders 16in., stroke 3ft. The former is used for operating the rock-breaker and as much of our milling-gear as it is equal to on occasions when we run short of water. The latter is used for winding and pumping and furnishing steam for ore-treatment. " Water-power. —By means of two large dams on the head branches of the Ohinemuri River we have raised these streams at that point 16ft., and by means of fluming and open channels the water is conveyed to the .works, two miles and a half. The race is capable of bringing twenty-five sluice-heads. The power is obtained from two Pelton wheels placed at the bottom of a pit 52ft. deep, whence the waste water is conveyed again into the river at the lowest available point by a tunnel 1,200 ft. long. The Peltons are 7ft. diameter over all, and are fed by a column 42in. in diameter, supplied with double nozzles for each wheel and with regulating-valves. The power is conveyed from these wheels to the gear on the surface by a rubber belt 20in. wide. " Reduction Gear. —We have two large rock-breakers, but use only oue. This is capable of reducing 40 to 50 tons in eight hours fine enough for our stamps. " Stamps. —Thirty stamps, each Ocwt., run ninety-two to ninety-five beats per minute, fed automatically, and stamping through steel-wire gauze, 3,600 perforations each square inch, reduce in twenty-four hours 45 to 50 tons of ore to finest pulp, which falls into a trough carrying a special conveyor, which passes it along to the elevator ; thence it is raised to the rotary roaster or, optionally, to an ore-bin capable of containing 50 tons. " Amalgamating-paus. —These are known as the ' Combination mills,' similar to the old ' Wheeler ' —sft. diameter. We have eight of these pans, and treat about one ton as a charge for each pan. As our pulp has already been fined sufficiently, no pan-grinding is necessary, and therefore from three to four hours' agitation with 4001b. of mercury and chemicals, with steam, completes amalgamation, when the charge is allowed to flow into the settling-pans—Bft. diameter— where the mercury and amalgam are separated by gravitation, the pulp being gradually floated off, while the metal finds its way into cast-iron tanks, after being self-strained through inverted conical canvas bags. „ " Clean-up Pan. —The crude amalgam in due course is periodically taken from the canvas bag and dressed in a 4ft.-diameter pan, and again squeezed—this time into balls, ready for the retort. 6—C. 3.