On the interior of each pocket, under the tracks, has been erected a series of deflectors on an 8-inch pitch, each deflector being constructed of wood, and protected against excessive wear by sheet iron. The coal slides from one deflector to the next lower, and in this way prevents a straight drop of the coal to the concrete floor below, thereby reducing the breakage to a minimum.
Transversely across the building on each side of the lower columns a reinforced concrete wall 4 inches thick has been constructed, forming dirt pockets. These pockets receive the screenings from the coal as it runs over the screens in the chutes. These screenings are shoveled out through openings in the bottom of the dirt . . .
pockets into carts and taken to a screening plant, where they are deposited in a large hopper and discharged onto a vertical bucket-conveyor, carried up and run through a revolving screen and separated into the smaller sizes of coal. This plant is electrically operated.
Under the pocket in all driveways, granite block paving with grouted joints is laid on a gravel base. This paving runs also 30 feet out from either side of the pocket, around and under the screen house, and up to the scales and office.
Under the pocket in each bay is a 16-candle-power electric light, and under the roof over each separate pocket is a light and a reflector.
Water-Intake. A concrete water-intake of unique design, claimed to be the only one of the kind in the world, has recently been completed near San Bernardino, Cal., for the Arrowhead Reservoir and Power Company. The intake or tower (shown in Plate 26), which is built entirely of reinforced concrete, is 185 feet in height, 13 feet in diameter, and stands in an artificial lake in mountainous country at an altitude of nearly 6,000 feet above sea-level. The wall of the tower to the height of 125 feet is 24 inches thick; and from that point up, 15 inches thick. The cement, sand, and crushed rock to make the concrete were mixed in the ratio of 1:2:3, and the rein forcement consists of three-fourths-inch rods running circular and perpendicular. The tower was constructed in sections of six feet each, and was completed in about six months, at a total cost of about $40,000.
The Arrowhead Reservoir and Power Com pany, which for nearly twelve years has been working on a great dam at this place, had been experiencing difficulty for some time to keep the old intake clear of rubbish, which, on account of the strong suction, at times almost entirely shut off the flow of water. The new intake overcomes
the problem with a series of ten 20-inch valves, arranged on the sides of the tower in spiral form from the top to near the bottom, so that the water can be taken in at any level. The intake stands in an 880-acre artificial lake that at pres ent has a depth of over 35 feet, and that is sub ject to great fluctuations. The valves can be controlled from the top of the tower, and by the opening or closing of the different valves both the quantity and the pressure of the water can be readily and quickly regulated. Each valve is inclosed in a circular screen cage about 5 feet in height and 2 feet in diameter, seated on an elbow which turns up on the outer surface of the tower.
Concrete Chimneys. The first reinforced concrete chimney was built in 1898 by the Ran some & Smith Company for the Pacific Coast Borax Company, Bayonne, N. J. Since that time about 400 stacks have been completed. There are examples in nearly every State of the Union and in Canada. These stacks range in height above ground from 50 to feet, with inside diameter ranging from 4 to 18 feet, the majority of them being 150 to 200 feet high and 5 to 6 feet inside diameter.
One of the tallest chimneys in the United States is of concrete construction and located at Butte, Mont., at the mines of the Colusa Parrot Mining & Smelting Company.
The stack is feet high; its inside diameter, 18 feet. The walls of the lower 21 feet of the chimney are 18 inches thick; and above this is the double shell, the outer shell being 9 inches and the inner 5 inches thick, with a 4-inch air-space between them. The inner shell extends to a height of 101 feet above the base. The vertical reinforcement is by T-bars; and the horizontal reinforcement, of 1-inch by 1-inch T-bars, varies in spacing from 12 inches to 3 feet apart. A very rich mixture was used in the construction. The foundation of the chimney is unusual, consisting of a base 18 feet in depth, formed of molten slag in which steel wire rope, chain, and T-rails are embedded, and upon which is placed the reinforced concrete footing for the chimney proper.