Zur Theorie des Radiometers.

Leipzig, Johann Ambosius Barth, 1922. 8vo. 14 pp. Original printed wrappers. = An important contribution to the understanding of the radiometer effect, by the physicist Edith Einstein (1888-1960). "The Crookes radiometer (also known as a light mill) consists of an airtight glass bulb containing a partial vacuum, with a set of vanes which are mounted on a spindle inside. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement of electromagnetic radiation intensity. The reason for the rotation was a cause of much scientific debate in the ten years following the invention of the device" (Wikipedia). James Clerk Maxwell first gave a wrong, then a correct explanation. However, some subtleties still needed to be solved. "In 1920 Albert Einstein selected this topic as a suitable PhD thesis for his cousin Edith Einstein. She completed her doctorate, under the supervision of Paul Epstein but with considerable imput from Einstein himself" (Calaprice et al.). Later, in 1924, Albert wrote another paper on the radiometer effect, correcting Edith on a few issues. Published in the famous Annalen der Physik, vierte Folge, Band 69. This being the complete Heft 4, published on 30 November 1922. Minimal wear to spine ends, otherwise a very good, clean copy. Very uncommon. Calaprice et al., An Einstein Encyclopaedia, p. 160.