instrument for copying drawings
• (n.) An instrument for copying drawings on the same or a different scale; a form of the pantograph.
Ei'do·graph noun [ Greek ... form + graph .] An instrument for copying drawings on the same or a different scale; a form of the pantograph. 
An eidograph is an instrument for copying drawings, designs and the like reduced or enlarged , within limits, to any desired proportion. Some what on the lines of the pantograph, the eidograph comprises a slotted beam adapted to slide in a socket, having the axis in the center line of the slot. Underneath each end of the beam is a wheel; the wheels...
eidograph An instrument for enlarging or reducing drawings.eidography, eidograph An instrument for enlarging or reducing drawings.