Many interesting characters served at the Mint during the early years of operation. One was John Leonard Riddell, who served as melter and refiner at the Mint from 1839 to 1848, and, outside of his job, pursued interests in botany, medicine, chemistry, geology, and physics. He invented the binocular microscope. He also wrote on numismatics, publishing in 1845 a book entitled "Monograph of the Silver Dollar, Good and Bad, Illustrated With Facsimile Figures", and two years later an article by him appeared in "DeBow's Review" called "The Mint at New Orleans—Processes Pursued of Working the Precious Metals—Statistics of Coinage, etc." Riddell was not held in high esteem by everyone, however: his conflicts with other Mint employees were well-documented, and at one point he was accused of being unable to properly conduct a gold melt.