Smithsonian Studies in History and Technology, no. 32.
Medal ruling is a little known art by which pictures are mechanically produced from coins, medals, cameos, and other objects presented in relief. It made a sudden and spectacular appearance very early in the19th century, but with the advent of daguerreotype photography near the middle of that century, it disappeared almost as suddenly. Joseph Saxton (1799-1873), an extraordinary mechanician was caught up in those arts, and made exceptional contributions to both of them. His medal ruling machines were the first of their kind to have eliminated distortions from the resulting pictures. Among the scientific uses to which his final model was applied was a diffraction grating made for John William Draper, who took the first photograph ever executed of the diffraction spectrum. The only remaining model of the three machines Saxton is known to have built is now at the National Museum of History and Technology, Smithsonian Institution.
The daguerreotype Saxton took of Philadelphia's first Central High School and the State Armory is perhaps the earliest daguerreotype ever taken in the United States, and certainly represents the oldest American daguerreotype extant. It is now in the custody of the Historical Society of Pennsylvania in Philadelphia. A combination of Saxton's medal ruling and daguerreotype skills helped to produce a remarkable illustration of the second United States Mint, which was published in 1842 in Eckfeldt and Du Bois' Manual of Gold and Silver Coins, and which has been republished in this present study.