Jenkins attended the Bliss School of Electricity in Washington, D.C., where he met classmate Thomas Armat. With Armat acting as financier, the pair worked on and improved upon the design of the Phantoscope projector.
In the late nineteenth century, public fairs and expositions were an important way for cities to attract visitors. People were eager to see new technological developments on display. Atlanta hosted three such expositions in the years following the Civil War, meant to help foster recovery and economic development for the city. Jenkins and Armat held a public screening at the last of the three, in the fall of 1895 at the Cotton States and International Exposition, projecting Kinetoscope films with the Phantoscope. (The Kinetoscope had been invented in the late 1800s, and was a device that gave the impression of movement by moving a loop of film continuously over a light source with a rapid shutter.)
Jenkins and Armat split soon after the Exposition, with each party claiming the invention to be their own effort. The two worked independently on improving the Phantoscope.