11. Elliptical spur-gearing, used when a rotary motion of varying speed is required.

12. A spur-wheel geared internally with a pinion. The wheels rotate in the same direction (cf. 7).

13. Spur-gearing with oblique teeth, giving a more continuous bearing than 7.

14. Showing the transmission of power by rolling contact from one shaft to another obliquely situated with regard to it.

15. Different kinds of gearing for transmitting motion from one shaft to another arranged obliquely to it.

16. Two kinds of universal joints.

17. A method of transmitting motion from one shaft (the vertical) to another (the horizontal) by means of bevel-gearing, with a double-clutch for altering the direction of rotation. The bevel-wheels on the horizontal shaft are loose, and the direction of movement is determined by the side upon which the double-clutch is engaged. The clutch slides upon a key or feather fixed on the shaft.

18. Transmission of two speeds by gearing. The hand is shown on the loose left hand pulley of the lower three. When it is moved on to the middle pulley, which is keyed to the shaft carrying the small pinion, a slow motion is transmitted to the lowest shaft; but when, it is on the right-hand pulley, which is fast to the outer shaft carrying the large spur-wheel, a quick speed is transmitted.

19. Transmission of two speeds by means of belts. The two outer pulleys on the lower shaft are loose, the two inner fast. With the belts arranged as shown, the speed of the lower shaft is slower than when both are traversed to the right.

20. An intermittent circular motion in the direction indicated by the arrow is transmitted to the wheel A, by means of the oscillating rod D and the pawl B, from the reciprocating rectilinear motion of the rod C.

21. The continuous rotation of the shaft carrying the two cams or wipers gives to the rod A an intermittent alternating rectilinear motion. The rod is raised by the action of a wiper on the projection B, and it falls by its own weight. This contrivance is used in ore-stampers or pulverizers, power-hammers, &c.

22. The reciprocating rectilinear motion of the rod on the right produces intermittent circular motion of the wheel by means of the elbow-lever and the pawl. The direction of motion of the wheel is determined by the side on which the pawl works. This contrivance is used in giving the feed-motion to planing-machines and other tools.

23. The piston-rod and crank motion used in the steam-engine. The reciprocating rectilinear motion of the former is converted into the rotary motion of the latter through the agency of the connecting-rod (not shown).

24. An eccentric, such as is used on the crank-shaft of steam-engines for communicating reciprocating rectilinear motion to the slide-valves. It rotates round an axis not pushing through its centre.

25. Internal spring pawls for a ratchet brace. The ratchet can revolve only in one direction (counterclockwise), and as it does so the springs are gradually compressed and suddenly released in turn.

26. Friction pawl feed motion, silent. The arrow shows the direction of rotation of the wheel. The principle of the contrivance is obvious.

27. A heart-cam, by whose rotation uniform traversing motion is imparted to the vertical bar. The dotted lines show the method of obtaining the curve of the cam. Eight concentric circles are drawn with radii in arithmetical progression as shown, and they are divided into twelve equal sectors. The points on the heart-curve are determined by the intersection of radii and circles.

28. A quick-return crank motion, applicable to shaping-machines. This arrangement needs no explanation.

29. A crank motion, with the crank wrist working in a slotted yoke, thereby dispensing with the oscillating connecting rod.

30. A screw stamping-press, showing how rectilinear motion may be obtained from circular motion by means of a screw.

31. A screw-cutting mechanism. The rotation of the left-hand screw produces a uniform rectilinear movement of a cutter which cuts another screw-thread (seen on the right). The pitch of the screw to be cut may be varied by changing the sizes of the engaged spur-wheels at the bottom of the frame.

32. The movable headstock of a turning lathe. By turning the wheel on the right hand motion is communicated to the screw, thus causing the spindle with the centre at its end to move in a straight line.

33. Swivelling-gear for car wheels. The essential part is the operation of the endless screw on the worm-wheel. The wheels are connected by a lever freely joined to the cranks.

34. Diagrammatic representation of screw-gear to operate three worm-wheels in the same direction, for chucks, etc. The method of working is obvious.

35. A mutilated screw for sliding into a nut having corresponding parts of the thread cut away, to be fixed by a partial turn. It is used for the breech-pieces of cannon.

36. Variable radius lever, operated by a crank motion to give variable angular reciprocating motion to a shaft.

37. Hand or power feed-gear, for a drill, boring-machine, &c.

38. A method of doubling the length of stroke of a piston-rod or the throw of a crank. A pinion revolving on a spindle attached to the connecting-rod is in gear with the fixed lower rack and also with the upper rack, which is carried by a guide-rod above and is free to move backward and forward. The connecting-rod communicates to the pinion the full length of stroke, and since the lower rack is fixed the pinion rotates, thus making the upper rack travel twice the length of the stroke.

39. A toggle-joint arranged for a punching-machine. The lever at the right operates upon the joint or knuckle of the toggle on the left, thus raising or lowering the punch.

40. A stone-breaker, with chilled-iron jaw-faces and a toggle or knapping motion.

41. An ellipsograph. The oblique traverse-bar carries two studs, which slide in the grooves of the cross-piece. By the motion of the traverse bar the attached pencil is made to describe an ellipse.

42. Link-motion valve-gear of a locomotive engine. The rods of the two eccentrics on the right are jointed to the curved slotted bar called the link, which can be raised or lowered by the system of levers terminating in the handle at the left. The link carries in its slot a slide and pin connected with another arrangement of levers, which operates on the valve-rod as shown. If the link be so arranged that the slide is at its centre, then the movement of the eccentrics will simply cause the link to oscillate about the pin of the slide, and the valve-rod will be at rest. Otherwise the valve-rod will move, and, if the slide be at an end of the link, steam will be admitted during nearly the whole stroke, but if the slide occupy an intermediate position the period of admission of steam is shorter In the latter case the steam is worked more or less expansively.

43. Joy's locomotive valve-gear operated by the connecting-rod. The rod A is connected to the starting-lever to reverse, vary, or stop the distribution of steam by the slide-valve (cf. 42).

44. Side shaft motion for operating Cornish, Corliss, and spindle valves.

45. The "Geneva stop", used in Swiss watches to limit the number of revolutions in winding up. The convex part a b of the upper wheel acts as the stop.

46. A form of strap brake used in cranes and other hoisting-machines. If the lever be depressed the ends of the brake-strap are drawn toward each other, and the strap is thus tightened on the brake-wheel.

47. A dynamometer, used to ascertain the amount of useful effect given out by a motive-power. A is a smooth pulley secured on a shaft as near as possible to the motive-power. Two blocks of wood, or one block and a series of straps fastened to a band or chain, are fitted to the pulley, and these are so arranged as to bite or press upon the pulley by means of the screws and nuts on the top of the lever D. At the end of D is a scale, and the stops C, C' prevent the lever from travelling far from the horizontal position. The shaft being in motion, the screws are tightened and weights are placed in the scale until the lever takes the position shown at the required rate of revolution. The useful effect is then represented by the product of the weight added and the velocity at which the point of suspension of the scale would revolve if the lever were attached to the shaft.

48. A diagrammatic sketch of a form of groove for ball-bearings, running horizontally, showing the points of bearing in the grooves.

49. A diagrammatic sketch of a roller bearing for a vertical shaft, with steel balls between the ends of the cone-rollers to separate them and reduce their friction.

50. A diagrammatic sketch of a roller bearing for a wagon axle, with balls between the roller ends to separate them and prevent internal friction. Two views of the bearing are shown in order to make the arrangement perfectly clear.

51. A recoil escapement for clocks. The anchor H L K is made to oscillate on the axis a by the swing of the pendulum. The teeth of the escapement-wheel A come alternately against the outer surface of the pallet A and the inner surface of the pallet D. The pallets are not concentric to the axis a, and therefore a slight recoil of the wheel takes place after the escape of a tooth (whence the name of the escapement). When the pallets leave a tooth the teeth slide along their surfaces, giving an impulse to the pendulum.

52. A dead-beat or repose escapement for clocks. The lettering is as in the preceding. The pallets are concentric with the axis a, and thus while a tooth is against the pallet the wheel is stationary.

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.

62. A gas-engine governor. The revolving cam throws the vertical arm of the lever far enough to close the gas-valve when the speed increases beyond the normal.

63. A plan view of the Fourneyron turbine. In the centre are a number of fixed curved "shutes" A, which direct the water against the buckets of the outer wheel B, thus causing it to revolve.

64. The Jonval turbine. The shutes are on the outside of a drum a, stationary within the casing b. The wheel c is similar, with the buckets exceeding the shutes in number and set at a slight tangent instead of radially.

65. Montgolfier's hydraulic ram, by means of which a small fall of water throws a jet to a great height or furnishes a supply at a high level. The action of the water on the two valves, which are alternately open, is easily comprehended. The right-hand one is pressed down by a weight or spring. The elasticity of the air gives uniformity to the efflux.

66. Common lift-pump. During up-stroke lower valve opens and piston-valve closes, and water rushes up to fill the vacuum created. During down-stroke lower valve closes and piston-valve opens, and the water passes through the piston. At next up-stroke it is raised by the piston and passes out by the spout.

67. Common force-pump, with two valves. When piston rises, the suction-valve opens and water enters the vacuum. When piston descends the suction-valve closes and the outlet-valve opens, and the water is forced up through the outlet-pipe.

68. A double-acting piston-pump with four valves.

69. A hydrostatic press. Water forced by the pump through the small pipe into the ram cylinder and under the solid ram forces the latter up. The amount of force exerted on the ram bears to the pressure on the plunger the same ratio as the area of the ram does to the area of the plunger. Thus, if the area of the plunger cross-section be two square inches and that of the ram four square feet, a pressure of ten pounds on the former will produce a pressure of 2880 pounds on the latter, or nearly 26 cwts.

70. The Bourdon aneroid gauge. B is a bent tube closed at the ends and secured at its middle, C. The ends of the tube are connected with a toothed sector gearing with a small pinion which carries the indicating pointer. Pressure of steam or other fluid admitted to the tube tends to straighten it, thus moving the pointer more or less.

71. An air-pump with foot and head valves.

72. Root's rotary engine, used as blower and also as pump. It has two rotating pistons of special shape, so arranged that air or water may be caught and carried forward by their motion.

73. Waygood's patent hydraulic balance lift. A is the lift-cylinder communicating with the interior of the cylinder and ram B. The cylinder C and ram D are loaded to nearly balance the cage and ram A, and the load is raised by admitting pressure water to cylinder C.

74. An epicyclic train. The wheel A, which is concentric with the revolving frame C, gears with F, which is fixed to the same axle as E. E gears with B and D, the latter on the same axis as A. The driving motion may be communicated to the arm and one extreme wheel, A or D, in order to produce an aggregate motion of the other extreme wheel; or motion may be given to the two extreme wheels, thus communicating motion to the arm.

75. Another form of epicyclic train. F G is the arm, secured to the central shaft, A, upon which are loosely fitted the bevel-wheels C, D. The bevel-wheel B turns freely on F G. Motion may be given to the two wheels C, D to produce aggregate motion of the arm, or to the arm and one of these wheels to produce aggregate motion of the other.

76. Common D slide-valve with three ports: a diagrammatic section.

77. Another form of slide-valve, partly in equilibrium. The arrows show the movement of the steam. (Like the other figures on this plate, this one is a diagrammatic section.)

78. A variable cut-off valve on the back of the main slide, the rod of which (seen above) can be revolved by hand or from the governor to vary the opening of the cut-off valves.

79. Double-beat valve, with sunk seating.

80. Reducing-valve, which can be adjusted by the balance weight to pass fluids from a high to any lower pressure.

81. An equilibrium-valve.

82. India-rubber disc and grating valve.

83. A four-plunger valve, used for double-power hydraulic lift-cylinders employing a trunk piston For the low power the pressure-water acts on both sides of the piston; for the double power it acts only on the back of the piston, the front side being then open to the exhaust.

84. Sketch of the Corliss valve-gear, operated by a single eccentric. It has two steam and two exhaust valves of an oscillating cylindrical type, worked from pins on a rocking wrist-plate. The steam-valves have trips regulated by the governor.

85. Corliss valve, with rectangular rocking spindle.

86. A favourite type of vertical overhead cylinder screw engine, with half-standards and distance rods, one, two, or three cylinders, simple or compound. The condenser is usually in the back standards and the pumps behind.

87. A pedestal bearing, with four brasses and set-screw adjustments.

88. A hydraulic oil-pivot for vertical-spindle. Oil under pressure is forced into the channels between the bearing faces, the area and pressure being adjusted to the load. The surplus oil is returned from the oil-well to the pump.

89. An engine crosshead, with adjustable guide-brasses, set up by taper keys and nuts.

90. An equalizing lever to distribute the load on two car springs.

91. Korting's water-jet condenser. It requires three feet head of condensing water

92. An automatic tipping-scale. When full, to equal the weight, it falls and tips by striking a fixed stop. The scale then turns over and returns to its position to be refilled.