Beschreibung:

EINSTEIN, Albert (1879-1955). Four typed letters signed ("A. Einstein"), two with equations in Einstein's hand, one with autograph postscript, to Jakob Mandelker (1900-1966), in German, Princeton, 22 January 1950-15 September 1954. Together 6 pages, 4to and 8vo, with original envelopes . [ With :] Carbon draft of letter from Mandelker, in German, responding to Einstein's letter of 15 September 1954. 5 pages, 4to . [ With ]: Carbon copy of paper by Mandelker, in English, "The Derivation of a New Kinetic Energy Formula from the Energy Aspect of Matter," Atlanta, [1954], with 7-line autograph comment by Einstein (signed "A.E."), in German. 19 pages, 4to, equations, underlines and some corrections in ink in Mandelker's hand, other corrections in pencil, staple holes in left margin . Einstein replies, in the negative, to Jakob Mandelker's attempts to offer a mechanical proof for the theory of relativity. Mandelker, born in Galicia while it was still part of the Austro-Hungarian Empire, was educated in Vienna, where he earned a doctorate in Technical Science. Specializing in civil engineering and reinforced concrete and steel constructions, he worked in Vienna until 1938 and thereafter in Shanghai, until he emigrated to the United States in 1948 under the auspices of the Institute of International Education, Inc. From 1949 until his death, he taught in the Department of Engineering Drawing and Mechanics at the Georgia Institute of Technology. During that period his research interests shifted to relativity and gravitation in relation to motion and energy. In addition to his contributions to professional journals, one of which is represented here, he published four books on these subjects: Principles of a New Energy Mechanics (New York 1950), A New Theory of Gravitation (New York 1951), Matter Energy Mechanics (New York 1954), and Relativity and the New Energy Mechanics (New York 1966). Mandelker summarized his argument in the paper here submitted to Einstein: "... the motion of a body whose mass increases with the velocity is equivalent to motion with resistance ... In this case, however, kinetic energy cannot become equal to the work performed, but must remain smaller. The total work, then, subdivides into two parts: first, kinetic energy ... and second, a non-kinetic, velocity dependent energy (of dissipative nature) arising during motion." Transforming Einstein's formula E=mc 2 into m=E/c 2, Mandelker posited that "every piece of matter has to be considered as possessing energy of constitution of the value mc 2. The adoption of the relation E=mc 2 as a universal expression for the dependence of the mass of a body on its energy content is incompatible with the classical assumption of a constant mass, i.e., as being independent of the velocity. Every change in the energy content of a body brings about a corresponding change in its inertia mass ... Hence, the first consequence of the new energy concept of matter is the recognition that the constant mass m' of classical mechanics has to be replaced by a mass m varying with the energy content, thus changing fundamentally the whole basic structure of mechanics." The correspondence opened in early in January 1950 with Mandelker's first letter to Einstein (not present here), to which Einstein replied by stating that the transformation proposed by Mandelker did not exist. In response to a further communication from Mandelker, Einstein sent an explanation of why he disagreed with Mandelker's argument. 22 January 1950 : "I am making a second and last attempt to demonstrate to you your fundamental error. You are not to conclude from my silence in the future that I agree with you." After commenting on three aspects of Mandelker's argument and correcting his equations, Einstein adds in a postscript: "It seems that you have not understood correctly the nature of a group of coordinate transformations and the significance of co-variance on such a group." 26 August 1952 : Einstein replies to