I N T R O D U C T I O N T O V O L U M E 1 5 l x i i i 20 km/s in the direction of the constellation Hercules, toward a point known as the solar apex. This was discovered in the eighteenth century by William Herschel, based upon small changes in the position of nearby stars, relative to earlier obser- vations by the first Astronomer Royal, John Flamsteed (Herschel 1783).[30] The motion toward Hercules and Miller’s claim that even the walls of a building might be sufficient to drag ether along with the apparatus undoubtedly inspired Auguste Piccard’s plans to, as Einstein put it, “Miller-in-a-balloon” (Doc. 85). Piccard hoped to time the season of his measurements, and conduct them at night, in order that the three known components of the Earth’s motion (rotational, orbital, and toward the solar apex) would all be roughly parallel, thus giving the largest possible motion with respect to the putative ether (Doc. 74). He detected no such motion, in agreement with Einstein’s relativity postulate. As Miller tried to mea- sure the absolute velocity of the solar system, astronomy was undergoing a revolu- tion that revised the estimate of this velocity upward by an order of magnitude. Coincidentally, a major contribution to this revolution was presented by Gustaf Strömberg, an astronomer at the Mount Wilson Observatory, at the same session of the National Academy of Sciences in 1925 at which Miller announced his results. Josef Weber, who had shown that Miller’s results exhibited a minimum ether drift when they should have shown a maximum—when the Earth’s motion was oriented roughly toward the solar apex (Abs. 188 and Weber 1926b)—informed Einstein of Strömberg’s results, which showed that the solar system moves at a velocity of some 300 km/s with respect to certain old stars (now called halo stars), globular clusters, and other galaxies (Strömberg 1925). The best interpretation was, and is, that the solar system orbits the center of the galaxy at this velocity and that the ear- lier observed velocity of 20 km/s is merely the velocity with respect to nearby stars that share the solar system’s orbital motion about the galaxy’s center. This lower velocity was still expected by experimenters like Piccard (Doc. 74) who were not, like Miller, in the fortunate position of conducting their experiments on the grounds of the world’s leading observatory. Strömberg’s results, together with work by the Dutch astronomer Jan Oort and the Swedish astronomer Bertil Lindblad, estab- lished our current picture of the structure and dynamics of the galaxy. Since Ström- berg was at Mount Wilson, he was eventually successful in pinning Miller down to a specific claim of the solar system’s motion through space: 200 km/s in a direction about 23 degrees away from the solar motion in the galaxy (Strömberg 1926). This was close enough to Strömberg’s conclusions to put new heat into the reception of Miller’s work. Miller’s claim that his results agreed with the exciting discovery of the Earth’s motion about the Galactic center caught the imagination of many senior physicists, as suggested by correspondence between Wilhelm Wien and Schrödinger. Their