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.