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Dr. Albert Einstein: Theoretical Physics, Relativity and the Photoelectric Effect, 1935

The Electron

In 1897, the source of electromagnetic fields was discovered: the electron. At the time of its discovery, the electron possessed the smallest mass known. It also carried the smallest electric charge known. Because of its charge, it was found to be the source of electromagnetic fields. However, the electron posed a problem for scientists grappling with electromagnetic theory. As is discussed above, electromagnetic theory dealt with fields and waves, entities that were thought to be continuous and without mass. Electrons are neither continuous nor without mass: they are individual, charged particles that have mass. Electrons thus did not "fit into" electromagnetic theory as it was understood in the late 19th Century. They posed yet another riddle for Einstein and his contemporaries.

Ensuring that Einstein would indeed be present for Medal Day ceremonies posed a problem for The Franklin Institute's Dr. McClenahan. Following are a series of letters detailing the Medal Day exercises and making every effort to accommodate Einstein in hopes of securing his attendance.