What is difference between a Barograph and Barometer?

A Barograph is a self-recording barometer, wherein a continuous trace of the atmospheric pressure is made on a barogram which is fixed to a rotating drum actuated by clock-work. This records the pressure changes shown by a mercury barometer, but the type in commonest use is a modified aneroid barometer, sometimes called anAneroidograph. It is more useful for indicating fall and rise of atmospheric pressure than for giving the actual pressure at any particular time.