Manograph - Definition - Law Dictionary Home Dictionary Definition manograph

Definition :

An optical device for making an indicator diagram for high speed engines It consists of a light tight box or camera having at one end a small convex mirror which reflects a beam of light on to the ground glass or photographic plate at the other end The mirror is pivoted so that it can be moved in one direction by a small plunger operated by an elastic metal diaphragm which closes a tube connected with the engine cylinder It is also moved at right angles to this direction by a reducing motion called a reproducer so as to copy accurately on a smaller scale the motion of the engine piston The resultant of these two movements imparts to the reflected beam of light a motion similar to that of the pencil of the ordinary indicator and this can be traced on the sheet of ground glass or photographed