flat and wire ropes, work in various kinds of shafts. The particulars in each case extend over a period of twelve months, and tables are given for each mine, showing the quantity hoisted and the cost of materials used, not only in the shaft but at the engines, and in filling and landing.

From the various tables I have compiled the following, showing the mean depth, the quantity extracted in tons, the cost per ton, and the cost per ton per 100 metres at the four different mines.

At Dolcoath a little over 42 per cent. of the cost was in the shaft, 37 per cent. at the engine, and 21 per cent. (nearly) for filling and landing.

HOISTING MACHINERY IN CALIFORNIA AND NEVADA.

The simplest form of steam hoist, and the one usually employed in California and Nevada, for depths of a few hundred feet, especially if used in connection with pumps, is a steam engine with eight to ten inches diameter of cylinder and sixteen inches stroke, with or without link-motion to the valves, the engine only requiring to run one way. Upon the crank shaft is a pinion, grooved generally with a large V, the inner faces having an inclination toward each other of 60 to 90 degrees. This pinion gears by friction into a large V-wheel, proportioned to the size of the other, so as to hoist in the shaft from 200 to 300 feet per minute.

This large V-wheel usually forms one flange of the winding drum, and upon the opposite end of the drum is a second flange of the same diameter as the V-wheel, but with its periphery broadly recessed to receive a friction strap. The winding drum is made of boiler-iron, and is riveted securely to a projecting rim cast on the inner side of each of these wheels. The dimensions of this drum are usually 2 feet 6 inches diameter by 2 feet 6 inches long. The diameter of the large-friction Vwheel is 4 feet, and of the brake-wheel the same. The whole is keyed upon a shaft 3 to 4 inches in diameter, and is mounted upon a wooden frame swinging upon a hinge. By means of a lever the large V-wheel is pressed firmly into contact with the fixed pinion on the engine shaft while hoisting. While lowering, it is thrown out of contact, and being perfectly detached from the engine, is free to unwind, its movement being controlled by the application of the friction band. The motion of the engine is controlled by the throttle-valve, and continues all the time in one direction, it being used only during the hoisting.

This construction for a hoisting engine is simple, durable, and comparatively safe for small loads and shafts that do not exceed two or three hundred feet in depth. For deeper mines and heavier work the drum-shaft is supported upon a frame which slides upon a secure bed, and can be pressed up to the V-pinion by levers, and the friction surface is increased by making several V-grooves instead of one, and giving them an acute angle.. Where two or more shafts are to be worked

from the same engine, a man is placed at each brake. Some engines drive as many as four winding drums from one crank-shaft. One of the disadvantages of this method is the unequal wear of the V-wheels, which require turning off as often as twice a year, and sometimes once in two months.

Hoisting gear of the kind just described is manufactured by the Union Iron Works. By means of long levers the engineer can control the engine while standing at the mouth of the shaft. The piston of the engine has two-feet stroke, and the fly-wheel is eight feet in diameter. The winding drum is three feet in diameter and three feet in length. This construction is characterized by extreme simplicity and great strength.

Another form of hoist much in use for the mines of the west is the common link-motion engine, with a light fly-wheel fitted with a good

brake, and a strong flanged pinion upon the end of the crank shaft. This pinion gears into a spur-wheel, keyed upon the shaft of the winding drum or reel. With this construction the engine and the winding

drum can be turned either way, and if two skips or cages are worked at the same time and from the same level in the mine, the cables are wound so that one unwinds while the other is winding up, one thus balancing the other. But where the points of departure in the hoisting change, one reel or drum is made with a hub-flange or clutch, so that it can be easily adjusted to wind from a greater or less depth, as required. In mining requiring a sudden change of distance of hoisting, (from either an upper or a lower level,) each reel and wheel should run independently and have a separate friction band. The pinions on the crankshaft are fitted with a clutch, which can be thrown in or out of gear when required to lower. The engine is under the control of one man, and each brake and reel under the control of another. When the bell strikes for either reel to hoist, the engine-man slows the engine to allow the clutch of the pinion to be put into gear. The brakeman then releases the brake and the hoisting commences. For stopping, the clutch is thrown out and the reel is held by the friction brake. In this way two or four shafts can be worked from one engine, and to any number of levels.

The above-described form of hoisting apparatus is illustrated by the annexed cut, giving a vertical and a side view of the machine with its foundation, as made by H. J. Booth & Co. It is here shown with a single bobbin for a flat cable; the spokes of this bobbin are of wood, and are not joined together by iron segments.

HOISTING AT THE MOUNT DIABLO COAL MINES.

At the Mount Diablo collieries the coal is hoisted in cars up a slope of 37° and 327 feet long, by an engine with a 14 by 30-inch cylinder. The crank-shaft carries a fly-wheel 12 feet in diameter, and a pinion 2 feet in diameter, geared into a spur-wheel 6 feet in diameter, which forms the end or flange of the winding drum. There are two drums, so connected by a clutch gearing that they can be easily disconnected at any time if desired. These drums are of iron, covered with wood, and are about 19 feet in circumference. A powerful brake, worked by the foot of the engineer, is fitted to the circumference of the fly-wheel, and is capable of stopping the engine very quickly. The engine makes 120 double strokes in a minute, and the usual time of hoisting a car carrying about one ton of coal is thirty seconds. Only one car is hoisted at one time, and about 200 are drawn up in the course of ten hours. But this is not the limit of the working capacity. As many as 270 have been taken out in that time, and the number could be exceeded if desired. Round iron wire rope, of an inch in diameter, is used, and passes over rollers about 3 feet in diameter. In some of the pits a flat wire rope, winding upon a reel, has been substituted.

At the Pacific Coal Mining Company's mines, near Mount Diablo, a very well constructed shaft was sunk vertically to a depth of 400 feet, and was provided with excellent hoisting works from the establishment of H. J. Booth & Co. The engine of 75-horse power was geared to a bobbin-shaft. There were two bobbins, winding inversely; flat iron cable, balanced; a link motion, and an ordinary brake, operated by the foot of the engineer. The pumping was performed by a separate engine of 150-horse power, 15-inch plungers, and a lift-pump.

HOISTING UPON THE COMSTOCK LODE.

Upon the Comstock lode, in Nevada, preference is given to one heavy,

short-stroke engine, with balance valves and link motion; a pinion upon the crank-shaft; heavy spur-wheel, and flat winding cable.

The mines on the Comstock lode which have large hoisting works and wire cables include the Chollar-Potosi, Empire, Gould & Curry, Hale & Norcross, Imperial, Lady Bryan, Savage, and Sierra Nevada. An engine recently put up by the Risdon Iron and Locomotive Works, of San Francisco, has a 20-inch cylinder with 40-inch stroke, with 3 feet 6 inch pinion, 12-feet spur-wheel, 14-inch face by 34-inch pitch, a single winding reel for flat cable, 5 feet in diameter, sheave, or shaft pulley, 8 feet in diameter. With this it is intended to work from a depth of 2,000 feet.

HOISTING IN GUIDED CAGES.

In each of the methods described the mineral, having been taken to the shaft, is either dumped in a pile and then shoveled into the bucket or skip, or is dumped through a chute directly into the skip, and the empty car is returned to the face. But this necessitates a rehandling of the mineral, which, when it reaches the surface, must be again dumped into a car or wagon, by which it can be delivered at the proper point away from the shaft.

These and other considerations have led to hoisting the car and load together to the month of the shaft. This effects a great saving in time, labor, and wear and tear of apparatus. It is the method adopted in the mines upon the Comstock lode, and in all well-appointed vertical shafts of any considerable depth elsewhere. To effect this, a compartment of the shaft is fitted with vertical stringers, or "guides" of wood or iron, extending from the top to the bottom, which serve to guide the movement of a platform cage, into which the car can be placed. The platform is fitted with rails of the same gauge as the track, and the car is rolled upon these and secured by bolts. The platform is a little smaller than the compartment of the shaft, and forms the bottom of a framework of iron, by which it is suspended. The frame rises above it on each side and connects with a cross-piece above the car, to which the hoisting cable is attached. The platform and the framework together form the "cage." By means of projecting ears or bars of iron or steel rubbers on each side, at the top and bottom, which partly embrace the guides, it is kept from contact with the sides of the shaft, and thus glides freely up and down. The only friction is between the rubbers and the guides, and this friction, in truly vertical shafts, is very slight. The shaft becomes, in fact, a vertical railway, and is a continuation of the tramways below, uniting them with the distributing tracks above. Tramming and hoisting thus become a connected and continuous operation. A carload of mineral is rolled to the bottom of the shaft and placed upon the platform, the signal is given to the engineman above, and the load starts upon its vertical journey.

Most of the mines at Virginia City and Gold Hill, upon the Comstock lode, and in other parts of Nevada, and the principal deep mines in California, with vertical shafts, now use the cage. It is single, large enough for one car only, but the hoisting is very rapid, from 500 to 1,200 feet per minute, (8 ft. to 20 ft. per second,) and with heavy loads weighing from 5,000 to 8,000 pounds.

The construction of the cage, as I have remarked, is very simple, being usually a square plank platform with a track, upon which the car stands, and suspended by a kind of stirrup-frame of iron at each side to an arched cross-bar of iron at the top, through the center of which the rod of suspension passes freely, and is firmly bolted just below to a