In the first accumulator which is still in use the ram was attached to
the foundation while the cylinder rose and fell as the pressure was
utilized. The weights were annular in shape and were hung upon the
outside of cylinder. In the modern types of accumulators the cylinder
is stationary and the ram supporting the weights is made to rise and
fall.
_By means of a hydraulic accumulator a uniform pressure can be
established and maintained on all parts of a hydraulic main or system._
[Illustration: