John Phipps writes:

Joseph Saxton improved on Gobrecht's medal-ruling machine and reduced distortions to reproduce an image of a medal for reproduction in a book or catalogue.

In this machine, a medal is placed in a horizontal position. A stylus is passed over the surface and the resulting line is cut by a graver into the surface of a horizontal copper plate. The position is changed in small increments forming a series of parallel lines that create the appearance of relief on the copper plate. The image on the plate appears reversed, but when inked and impressed on paper, the image is properly aligned.

Eckfeldt and DuBois used Saxton's third version of the medal-ruling machine, now powered by steam, to produce engravings of coins in the Mint Cabinet for their 1842 book, A Manual of Gold and Silver Coins of All Nations Struck Within the Past Century.

Also illustrated was an image of the Second Philadelphia Mint. Saxton made a daguerreotype of the Mint, Christian Gobrecht made a small relief model, an electrotype shell was made and used in place of a medal. A description of the process is in pages 186-188 of the book.

This marked a brief period of time when a daguerreotype and medal-ruling process were both used to create a printing plate. If photography had developed a decade earlier, it is likely that the medal-ruling technique would never have been used for book illustration.

To read the earlier E-Sylum articles, see:
ARTHUR HENRY FRAZIER (1899-2000)(https://www.coinbooks.org/v25/esylum_v25n39a14.html)
WAYNE'S NUMISMATIC DIARY: JULY 30, 2023(https://www.coinbooks.org/v26/esylum_v26n31a26.html)