power can be obtained from the main wires at almost any point and at a moment's notice. Flexible wires are used between the mains and the hoist motor for conducting the current. On Constitution Wharf, in Boston, a large forty-five horsepower motor is used to drive an elevator and also a long line of shafting running the entire length of the building, from which four friction whip hoists are operated. These whip hoists are used in handling light loads rapidly. They are comparatively inexpensive and do away with dummy engines, or of a horse at one end of a rope, slowly pulling up a barrel or bale at the other end, consuming a great deal of time, patience and money. These small friction whips, after the design used at Constitution Wharf, should receive the approval of mill men for use in cotton, wool, or cloth storehouses. To-day, in a great many places, a dozen or more men are required to do the same amount of work that two men with a whip hoist could perform more quickly and easily. An arrangement has been designed by the ThomsonHouston Motor Company in which a travelling overhead trolley carriage is used in connection with the friction hoist. With this arrangement a load can be picked up at one part of the storehouse and deposited in another part at any height desired. It might be well to again press upon you the fact that the freedom from danger of fire is a great point in favor of electric hoists, especially where cotton and wool are to be handled. Fig. 11.- ELECTRIC HOIST, SIDE VIEW. Within the past year electricity has been applied successfully to elevators. The Thomson-Houston Motor Company has designed a machine for this special work. The hoisting drum is mounted upon the same bed plate as the motor, and is driven by means of worm gearing. The worm shaft is connected directly to the armature shaft by a coupling, insuring positive motion between the motor and hoisting drum. The principal feature of the machine, however, is the fact of the motor being so controlled, by means of a suitable controlling device operated from the car, that it is made to revolve in either direction, running the car up or down as desired. As the motor is entirely at rest when the elevator is not in use, it consumes no power except when the elevator is actually running. A saving of power is hereby effected in this form over any form of belt machine which can be used. The electric elevator can be operated at any speed, from the slowly moving freight elevator, running at a speed of fifty feet per minute, to the rapidly moving passenger machine, running at a speed of three hundred feet per minute. The fourth and last head to be considered is the application of electricity to power pumps. While the question of adapting electricity to pumping may not have so much interest to mill men in general as the previous points brought up, still it may be of sufficient interest to warrant bringing to your attention a form of pump which is being used to a great extent by the ThomsonHouston Motor Company in connection with its motors. This pump is manufactured by the Gould Manufacturing Company, of Seneca Falls, N. Y., and is of the triplex, single-acting type. Three single-acting plungers, with their cranks hung from the main shaft at one hundred and twenty degrees, are. worked in three vertical cylinders. Fig. 12 shows the general appearance of this type of pump. This arrangement is the best possible one for electric work, as it insures an almost constant load upon the motor at all points of the stroke. The Gould Manufacturing Company makes pumps of this design, in all sizes, from two-inch by four-inch cylinders for light work to twelve-inch by twelveinch cylinders for heavy work. Larger pumps than the latter size are in course of design. The table of tests given below shows the efficiency of the Gould eight-inch by eight-inch pump when operated by a fifteen horse-power motor. As shown by the record, the efficiency of the electric power pump is fully equal to the steam |