After spending nearly a decade abroad in London, England, Joseph Saxton made his return to Philadelphia in 1837. This homecoming marked a new chapter in his career, as he accepted a significant position at the Philadelphia Mint. His time at the Mint would prove to be highly productive, characterized by a series of important inventions and a pioneering foray into the nascent field of photography in the United States. Saxton's work during this period
solidified his reputation as a versatile inventor and a meticulous curator of scientific standards.
Overseeing Standards and Crafting Innovations
Upon joining the Philadelphia Mint, Saxton initially took on the role of superintending the making of machinery. This position leveraged his extensive experience as a watchmaker, engraver, and apprentice in a machine shop, skills he had honed both in Philadelphia and during his time in London. His expertise in precision mechanics was crucial for ensuring the quality and functionality of the Mint's equipment. Later, he transitioned to the role of curator of weights and measures, a responsibility that underscored the importance of accuracy in national and state commerce. In this capacity, Saxton was tasked with furnishing accurate sets of weights and measures to various governmental bodies, a critical function for maintaining standardized trade and scientific endeavors across the country.
His work as curator directly inspired several of his inventions. Among these was a mirror comparator, a sophisticated device designed for precisely comparing standards of length. This invention was vital for ensuring that official length measurements were consistent and accurate. He also developed a new form of dividing engine, another tool essential for creating precise scales and measurements. These instruments highlight Saxton's dedication to metrology and his ability to engineer solutions for complex measurement challenges.
Pioneering Photographic Endeavors
Beyond his work with weights and measures, Saxton also made a significant, albeit perhaps less known, contribution to the history of photography in the United States. In the fall of 1839, either around September 25 or October 16, he captured what is recognized as one of the oldest surviving photographs, or daguerreotypes, taken in the U.S. This was a remarkable achievement, placing him among the earliest practitioners of this new art form in America, following some earlier calotype and daguerreotype efforts in the spring and September of that year.
Saxton's photographic setup was a testament to his ingenuity and resourcefulness. The image was taken from the window of his office at the Philadelphia Mint, capturing the cupola of Central High School and a portion of the State Armory building. The process involved a sheet of polished metal for the image, a seidlitz powder box with a few flakes of iodine serving as a makeshift coating box, and a cigar box combined with a burning glass improvised as a camera. An iron spoon was even used to heat the mercury needed to develop the plate. The resulting picture, a historical artifact, is now owned by the Historical Society of Pennsylvania, with its first public mention appearing in the United States Gazette on October 24, 1839.
Continued Innovation and Influence
Saxton's inventive spirit during his time at the Mint extended beyond length standards and photography. He also developed a self-registering tide gauge, an instrument designed to automatically record tidal movements, which would have been invaluable for maritime navigation and scientific study. Another notable invention was an immersed hydrometer, a device used for measuring the specific gravity of liquids. These inventions demonstrate the breadth of his interests and his practical approach to solving scientific and engineering problems.
His early photographic experiments also had a ripple effect. After taking his initial experimental images, Saxton sought out Robert Cornelius to obtain better photographic plates. This interaction sparked Cornelius's interest in photography, leading him to open one of the first daguerreotype studios in May 1840. Thus, Saxton's return to Philadelphia not only enriched the Philadelphia Mint with his mechanical and metrological expertise but also played a role in fostering the early development of photography in America.
