l x i i I N T R O D U C T I O N T O V O L U M E 1 5 his own data. In addition, Miller apparently changed his interpretation fortnightly (Doc. 72). Born was also an eyewitness to Miller’s apparatus, and, as Hedwig Born wrote to Einstein, was “horrified by the mess of the experimental arrangement” (Abs. 408). Michelson, too, was at Mount Wilson and Caltech at the time, and, as Epstein put it, was “very reserved, of course. The only thing I have got from him is that in his opinion Miller does not vary sufficiently the circumstances of the ex- periment” (Doc. 72). Several of Einstein’s correspondents commented on the implications of Miller’s results for astronomy. Most prominent was the Eddington’s statement that the ex- perience of astronomers with stellar aberration invalidated Miller’s claims (Eddington 1925c). Stellar aberration had played a key role in Einstein’s arguments in favor of the theory of relativity, since it shows a definite effect of the motion of the Earth relative to the starlight’s source on the direction of the propagation of light. Miller claimed that he could not confirm Michelson and Morley’s experiment at the high altitude of Mount Wilson. If this experimental result depended upon al- titude, Eddington demanded to know why observatories on mountaintops did not report any difference in stellar aberration from that observed at sea level. Miller’s preferred explanation for his results was some form of ether drag theory, as argued by Ludwik Silberstein (Silberstein 1925c). A clear implication of this interpretation would be that his observations on Mount Wilson were success- fully measuring the solar system’s motion through the luminiferous ether. Einstein himself regarded this as an interesting aspect of the experiment, commenting to Lorentz that it looked as if Miller’s data showed a constant direction against the fixed stars, though he doubted that this could be due to inertial motion. Neverthe- less, “if this is confirmed, then something fundamental lies behind it. Planck and Laue view it very skeptically” (Doc. 310). Emil Cohn criticized Miller for his refusal to state what motion of the solar sys- tem his results were actually consistent with (Doc. 64). Several of Einstein’s cor- respondents were suspicious of Miller’s failure to make a bold statement as to the velocity and direction of the Earth through space, including not only the Earth’s rotational and orbital motion within the solar system, but also the solar system’s motion through interstellar space. Miller merely stated in his 1925 papers that he was working on calculating such a quantity. Some scientists, such as Cohn, evi- dently suspected Miller of being unwilling to let his own theoretical model undergo a possibly falsifying test. As it happened, astronomers’ understanding of the motion of the solar system was undergoing a major transformation at this time. Previously it was believed that the solar system was moving within the system of nearby stars at a velocity of