Great numbers of these pumps are in use all over the United States.

A pumping engine that is remarkable for its size and peculiarities of construction is located at the Lehigh zinc mine, at Friedensburg, Pa. It was designed by Mr. John West, the company's engineer, and built by Merrick & Sons, of the Southwark Foundry, Philadelphia. It is a beam and fly-wheel engine, the steam cylinder being 110 inches in diameter, with a stroke of 10 feet. There are two beams on the same main center, from the outer end of which a double line of bucket and plunger pumps is operated. The crank-shaft is underneath the steam cylinder; and there are two fly-wheels, one on each end of said shaft, the crank-pins being fast in the hubs of the same. There are two connecting rods, which are attached one to each end of an end beam pin 28 inches in diameter. The main center and crank shafts are also 28 inches in diameter; each of the two plunger holes is 24 inches by 30 inches in section; and all the working parts are in proportion to those heretofore mentioned.

Perhaps no mining district has ever had to contend against greater difficulties in pumping than have faced the engineers of the celebrated Comstock lode, Virginia City, Nev. The mines are of great depth, in some instances 3,300 feet; and the water is hot, rising to 160 degrees Fahr. The machinery collected at this location is of great variety and magnitude. There are many Davey engines, both horizontal and vertical. The Union and Yellow Jacket shafts have compound fly wheel engines of very great power; the former having a beam, and the latter being horizontal, with cylinders placed side by side, and pistons connected to a massive cross-head, from the ends of which connecting rods lead to crank pins located in the hubs of the fly-wheels, which are overhung upon the ends of the main shaft. From the center of the cross head, a link runs to the main pump-bob, which operates a double line of 16 inch pumps, 10 foot stroke. The steam stroke is 12 feet. Depth of shaft, 3,300 feet.

The pumping machinery used in the iron and copper districts of Michigan usually consists of Cornish plunger pumps, which are operated by geared engines; the latter making from three to sixteen strokes to one of the pumps.

The largest plant of this type yet erected is that of the Calumet and Hecla copper mine, at Calumet, Mich. There are two lines of pumps, varying in diameter from 7 inches to 14 inches, and with an adjustable stroke varying from 3 feet to 9 feet. The object of the adjustable stroke is to diminish the capacity of the pumps in the dry season. Each line of pumps is driven from a crank placed on a steel spur-wheel shaft 15 inches in diameter, making ten revolutions per minute. The mortise spur-wheels have a diameter of 22½ feet at the pitch line, with two rows of teeth, each 15 inches face. The pitch is 4.72 inches. Engaging with the mortise wheels are pinions of gun iron 4 feet 6 inches in diameter, placed on steel shafts 12 inches in diameter, and making 50 revolutions per minute. The 12 inch pinion shafts are driven through mortise wheels 12 feet in diameter, and 24 inches face, by pinions 3 feet 9 inches diameter, which make 160 revolutions a minute. The pinion shafts are driven through a wire rope transmission from an engine located 500 feet distant. The rope wheels are 15 feet in diameter, and make 160 revolutions a minute. The engine is 4,700 horse power, and, in addition to driving the pumping machinery, does the hoisting and air compressing for the Calumet mine.

In the same building with the mine pump gearing is a duplicate arrangement for operating the man engine. In order to operate the mine pumps and man engine for the Hecla mine, it was necessary to use rock shafts, which are made of gun iron, and hollow; they are 32 inches in diameter outside, with 4½ inches thickness of metal. The pump rock shaft is 39 feet 4½ inches long over all, in two sections, and weighs 40 tons. There are rockers placed on each end of this shaft, one of which is connected with a crank on the mortise wheel shaft, and the other with the surface rods that work the pump-bobs. These rods are of Norway pine, 12 inches by 12 inches in section, and 1,000 feet long. There are two bobs, one above the other, with axes at right angles, each weighing about 25 tons. The connection from the upper bob to the lower has hemispherical pins and brasses to accommodate vibrations in right angled planes. The slope of the main pump is 39 degrees, and the machinery has been designed to raise water from 4,000 feet depth. The pumps are of the usual Cornish plunger type, with flap valves. There is an auxiliary engine, of the Porter-Allen type, for driving the pumps and man engines when the main engine is not working. It makes a 160 revolutions per minute, the same as the rope wheels The seeming complication of the arrangement is due to the fact that it had to be adapted to existing works, for increased depths, and put in without interfering with the daily operation of the mine.

The Calumet & Hecla Mining Company has also an extensive pumping plant at its stamp mills, which are located on the shore of Torch Lake, about four and a half miles from the mine. There are located here 3 pumping engines; two of which have a capacity of 20,000,000 gallons a day, and a third 10,000,000 gallons a day. The water is elevated between 50 and 60 feet, and is used for treating the stamped rock. Two of the engines are of the inverted compound beam and fly-wheel type; and the third is a geared pump, which has a horizontal double acting plunger, 36 inches in diameter, by six foot stroke, driven from the crank of a spur-wheel shaft.

The spur wheel is 12 feet diameter, 24 inches face, and contains 96 teeth. The pinion engaging with it has 27 teeth, and is fast on the fly-wheel shaft of a Brown horizontal engine, having a cylinder 18 inches in diameter, and a stroke of four feet. The steam pressure used is 110 pounds per square inch; and the engine has a Buckley condenser. The pump valves are annular, of brass, faced with rubber, and close by brass spiral spiral springs. Their external diameter is six inches, and the lift is confined to ½ inch. There are 91 suction and 91 delivery valves at each end of the pump. The maximum speed of this pump is twenty-six double strokes a minute.

The largest of the compound engines is named Ontario, and has a vertical low pressure cylinder 36 inches in diameter, and an inclined high pressure cylinder 17½ inches in diameter; the stroke of both being five feet. These are inverted over a beam, or rocker; and the pistons are connected to opposite ends of the same.

The beam attachment of the main connecting rod is made to a pin located above and midway between the pins for piston connections.

The main center of the beam and the crank shaft have their pedestals in the same horizontal plane. The throw of the crank is five feet. There are two differential plunger pumps, having upper plungers 20 inches in diameter, and lower plungers 33 inches in diameter, with a stroke of 5 feet. These pumps are vertical, and placed beneath the engine bed-plate, to which they are attached by strong brackets. The pump under the low pressure cylinder is worked directly from its cross-head by an extension of the piston rod. The other pump is worked by a trunk connection from the opposite end of the beam. The radius of the beam is but fifty inches, but the connections to it are made very long by links.

The lower plungers work through sleeves in diaphragms located in the center of the pumps. In these diaphragms, the openings for the delivery valves are made. These valves are similar in construction to those previously described for the horizontal plunger pump. Their diameter, however, is but 5¼ inches, instead of 6 inches, and there are 72 suction and 72 delivery valves for each pump. It will readily be seen that the action of these pumps is similar to that of the bucket and plunger; each pump having one suction and two deliveries for each revolution of the engine. The Ontario is designed to