Converging and Diverging Trains of M~hanism.Two or more trains of mechanism may converge into oneas when the two pistons of a pair of steam-engines, each through its own connectingrod, act upon one crank-shaft.
An excellent brake for very large cranes is Matthew's hydraulic brake, in which water is passed from end to end of cylinders fitted with reciprocating pistons, cooling jackets being provided.
With this arrangement the lift - ram and the two balance pistons are always in equilibrium, or, in other words, the ever-changing displacement of the lift-ram is automatically in balance.
As the ram ascends it apparently increases in weight, but this is balanced by the greater pressure on the two balance pistons as they descend, owing to the increase of the head of water acting on them.
The condition that the volume of the fluid mass shall remain unchanged requires that there shall be more than one piston, and that the -velocities and areas of the pistons shall be connected by the equation ~l.va=o.