freely, without allowing any leakage of the fluid. Applications of the stuffing-box are found in the steam-engine where the piston-rod passes through the cylinder cover, and where the valve spindle passes through the valve casing; also at the trunnions of the cylinder in an oscillating engine, and where the shaft of a centrifugal pump passes through the pump casing. Stuffing-boxes are also used to permit of the expansion and contraction of steam pipes. Fig. 199 shows an ordinary form of stuffing-box for the piston-rod of a vertical engine. AB is the piston-rod, CD a portion of the cylinder cover, and EF the stuffing-box. Fitting into the bottom of the stuffing-box is a brass bush, H. The space around the rod AB is filled with packing, of which there are a great many kinds, the simplest being greased hempen rope. The packing is compressed by screwing down the gland LM by means of the bolts P. When more than two bolts are used, the gland flange is generally made circular as shown in the lower left-hand view. For two bolts the gland flange is of the form shown in the lower right-hand view. When the gland is made of cast iron it is generally lined with a brass bushing. When the gland is of brass no lines are necessary. Steam Cock. Fig. 200 shows a good example of a cock, suitable for steam or water, and adjacent to it is a table of dimensions, taken from actual practice, for four different sizes. The two parts of Shaft Hanger with Adjustable Bearing. Figure 201 shows an excellent form of hanger and bearing for a shaft. The bearing is very long, and is held at the center of its length on spherical seats, which are formed on the ends of the vertical adjusting screws. The spherical seats permit of a slight angular movement of the bearing, a movement which is necessary with such a long bearing, to ensure that the axis of the bearing coincides with the axis of the shaft. The bearing and the vertical adjusting screws are made of cast-iron. Locomotive Connecting-Rod End. A modified form of box end is shown in Fig. 202. This is the design adopted on some roads for the large or HORSEPOWER OF GEARS 1. When the circular pitch is given—to find the horsepower capable of being transmitted by castiron gears with cut teeth: Multiply the pitch diameter of the gear by the circular pitch of the teeth, by the width of the teeth (all in inch measurements), and by the number of revolutions of the gear per minute. Divide the product by 550 and the result will be the horsepower the gear is capable of transmitting. Let D be the pitch diameter of the gear, C the circular pitch and E the width of the tooth (all in inch measurements), R the number of revolutions of the gear per minute and H. P. the horsepower the gear is capable of transmitting, then 2. When the diameter pitch is given to find the horsepower capable of being transmitted by castiron gears with cut teeth: Multiply the pitch diameter of the gear by the width of the tooth (both in inch measurements), and by the number of revolutions of the gear per minute. Divide the product by the Diametral pitch and by 175, and the result will be the horsepower the gear is capable of transmitting. Let D be the pitch diameter of the gear, F the width of the tooth (both in inch measurements), R the number of revolutions of the gear per minute of the gear, P the diametral pitch and H. P. the horsepower, then |