polygraph

n. A contrivance for producing manifold copies of a writing or drawing; -- made obsolete by later developments in copying technology; see xerography. [ 1913 Webster +PJC ]

☞ The writing or drawing is made with aniline ink on paper, and a reverse copy transfered by pressure to a slab of gelatin softened with glycerin. A large number of transcripts can be taken while the ink is fresh. [ 1913 Webster ]

Various names have been given to the process [ the gelatin copying process ], some of them acceptable and others absurd; hectograph, polygraph, copygraph, lithogram, etc. Knight. [ 1913 Webster ]