53. A lever escapement of a watch. The anchor B is attached to the lever E C, with the notch E. On a disk D, on the axis of the balance-wheel, there is a pin which enters the notch at the middle of each vibration, causing the pallet to enter in and retire from between the teeth of the scape-wheel. The wheel gives an impulse to each pallet alternately as it leaves a tooth, and the lever gives an impulse to the balance-wheel in opposite directions alternately.
54. Chronometer escapement. As the balance rotates in the direction of the arrow, the tooth V presses the spring against the lever, thus pressing aside the lever and removing the detent from the tooth of the wheel. As the balance returns V presses aside and passes the spring without moving the lever, which then rests against the stop E.
55. A parallel motion. To the left-hand end of the short vibrating rod in the centre the radius-rod is connected, to its right-hand end the beam, and to its centre the piston-rod.
56. The working of the pin in the oblique groove of the lower cylinder produces an alternating traverse of the upper shaft with its drum.
57. A drilling-machine. Rotary motion is given to the vertical drill-shaft by the bevel-gearing. The shaft slides through the horizontal bevel-wheel, but is made to turn with it by a feather and groove. It is depressed by means of a treadle connected with the upper lever.
58. Showing how to describe a spiral line on a cylinder. The spur-wheel on the right gears with the toothed rack shown behind, thus causing the pencil to traverse the cylinder vertically. It also produces rotation of the cylinder.
59. Wheel-work in the base of a capstan. The drumhead and the barrel can be rotated independently. If the former, which is fixed to the spindle, be locked to the barrel by a bolt, it turns the barrel with it (single-purchase). Otherwise the wheel-work comes into operation, and the drum-head and barrel rotate in opposite directions with velocities as three to one (triple-purchase).
60. A centrifugal governor for steam-engines. The central spindle is driven from the engine by the bevel-gearing, and the balls fly out under the action of centrifugal force. If the engine speed increases, the balls diverge farther, thus raising the slide at the bottom and so reducing the opening of the regulating-valve connected with it. If the speed of the engine decreases, an opposite result follows.
61. Crank-shaft governor cut-off gear. Two hinged centrifugal weights are coupled by links to the cut-off eccentric sheaves and returned by springs to the full open position.