Einstein, Albert (1879-1955). Ein einfaches Experiment zum Nachweis der Ampèreschen Molekularströme. Offprint from Verhandlung der Deutschen Physikalischen Gesellschaft 18 (1916). 8vo (230 x 157 mm). Original printed wrappers. Fine copy. FIRST EDITION, Presentation Offprint Issue. Offprints bearing the printed 'Überreicht vom Verfasser' formula on the wrappers were reserved strictly for the author's personal distribution to close colleagues, institutions, and family members. Copies of this specific wartime paper in original wrappers are scarce on the market. In 1915 Einstein and Dutch physicist Wander Johannes de Haas conducted gyromagnetic experiments leading to the discovery of the Einstein-de Haas effect, which corresponds to the mechanical rotation induced in a ferromagnetic cylinder suspended inside a coil when an impulse of electric current is sent through the coil. Einstein was very enthusiastic about the experimental results, stating that he and de Haas had 'given firm proof of the existence of Ampère's molecular currents' (quoted in Pais, Subtle is the Lord, pp. 245-246). After his collaboration with de Haas ended, Einstein published the present paper on the Einstein-de Haas effect, proposing a new experimental method for determining gyromagnetism. The Einstein-de Haas effect is now known to reveal a relationship between magnetism, angular momentum and electron spin; however, this was not understood at the time, as electron spin was not discovered until the 1920s. Weil, Albert Einstein Bibliography, 82. For further information on this lot please visit Bonhams.com For further information about this lot please visit the lot listing