(27.) Uniformity and steadiness in the rate at which machinery works, are essential both for its effect and its duration. The first illustration which presents itself is that beautiful contrivance, the governor of the steam-engine; which must immediately occur to all who are familiar with that admirable machine. Wherever the increased speed of the engine would lead to injurious or dangerous consequences, this is applied; and it is equally the regulator of the water-wheel which drives a spinning-jenny, or of the wind-mills which drain our fens. In the dock-yard at Chatham, the descending motion of a large platform, on which timber is raised, is regulated by a governor; but as the weight is very considerable, the velocity of this governor is still further checked by causing its motion to take place in water.
(28.) Another very beautiful contrivance for regulating the number of strokes made by a steam-engine, is used in Cornwall: it is called the Cataract, and depends on the time required to fill a vessel plunged in water, the opening of the valve through which the fluid is admitted being adjustable at the will of the engine man.
(29.) The regularity of the supply of fuel to the fire under the boilers of steam-engines is another mode
