The total solar eclipse which crossed from Alaska to Texas spurred many to make the trip West in 1878. As thoroughly documented in David Baron’s recent book, American Eclipse, the U.S. scientific community was eager to demonstrate capability to the scholarly world. Dr. Henry Draper, a medical doctor and former chair of physiology at New York University, assembled a group who watched the eclipse from the railroad outpost of Rawlins, Wyoming Territory. Although professionally known for medicine, Draper was an enthusiastic amateur astronomer who built an observatory in Hastings-on-Hudson, New York. Henry Morton of the Stevens Institute of Technology, James Barker of the University of Pennsylvania, Draper’s wife and research assistant Anna, and Thomas Edison comprised the eclipse-viewing party who departed New York on Saturday, June 13.

The foremost observation goal for the eclipse was study of the sun’s corona during the few minutes of totality. Henry Draper’s particular contributions to astronomy included documentation of solar spectra and well as celestial photography. Only a few years earlier, he earned renown for supervising photography of the transit of Venus. His half-ton photo-tele-spectroscope accompanied the group to their rudimentary observatory in Wyoming. Aside from the corona, there were secondary objectives for the scientific community. Edison himself had recently invented the tasimeter to measure heat from the solar rays, which he experimented with in a makeshift lab during the eclipse. Astronomers also used the darkness to search for Vulcan, a planetary body thought to be orbiting between the Sun and Mercury.

The eclipse occurred on July 29, 1878. To hedge against the misfortune of unclear skies, scientific groups scattered their camps across the path of totality, including on Pike’s Peak. A mere thirty miles from the Draper party was another group led by William Harkness of the U.S. Naval Observatory, a colleague from the transit of Venus project. Accompanying this group was Étienne Léopold Trouvelot, who captured the event in chromolithographs.

The Henry and Mary Anna Palmer Draper papers held at The New York Public Library consist primarily of correspondence with academics, artists, and scientists. After Henry Draper’s untimely death in 1882 (the result of weather exposure observing the stars of Orion), Anna Draper continued his work in the sciences as well as built a collection of ancient objects. She would become a benefactor of The New York Public Library, donating not only these papers but also establishing funds for acquiring further resources.