Ather und Relativitatstheorie. Rede gehalten am 5, Mai 1920 an der Reichs Universitat zu Leiden

Berlin: Julius Springer, 1920. 1st Edition. FIRST EDITION IN ORIGINAL WRAPPERS OF EINSTEIN'S LEIDEN LECTURE EXPLAINING AT LENGTH HIS THEORY OF THE ETHER ALONG WITH THOSE OF LORENTZ & MAXWELL. Very good + condition. "Einstein's lecture at the University of Leiden on the occasion of his appointment as a visiting professor summarized his current views on the ether and retrospectively looked at the development of his opinions on the physical properties of space" (Calaprice, The Einstein Almanac, 86).

In this lecture, Einstein recanted his earlier denial of the ether, writing: "Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this ether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it" (Einstein, Ather, 1920).

In this lecture, Einstein also sought "to reconcile his theory of relativity with his mentor's [Lorentz's] cherished concept of the aether... Einstein stressed that special relativity took away the last mechanical property of Lorentz's aether: immobility. However, he continued that special relativity does not necessarily rule out the aether, because the latter can be used to give physical reality to acceleration and rotation. This concept was fully elaborated within general relativity, in which physical properties (which are partially determined by matter) are attributed to space, but no substance or state of motion can be attributed to that "aether" (aether = curved space-time)" (Wikipedia). CONDITION & DETAIL: Berlin, Julius Springer, 1920. Complete in original cream colored wrappers. 8vo. (22 x 15cm). 15pp. Slight toning. Very good + condition.

ITEM: Ather und Relativitätstheorie. Rede gehalten am 5. Mai 1920 an der Reichs-Universität zu Leiden.