Original. Electrotype copy

Davis, Daniel, 1813-1887. Davis's manual of magnetism. Including also electro-magnetism, magneto-electricity, and thermo-electricity. With a description of the electrotype process. For the use of students and literary institutions. With 100 original illustrations · 1842

"1 plate with two engravings: the first is from the original engraved plate, the second from an electrotype made from it ... The electrotype process was important in photomechanical printing in that it was first used to copy daguerreotypes and was also used in experiments as a printing surface. Eventually Paul Pretsch used it with his photo-galvano-graphic process, and it was used continuously thereafter as a device to duplicate surfaces for printing in practically all the relief processes and some intaglio."--Hanson Collection catalog, p. 8