16 typed and handwritten letters between John Millis and Charles F., Sr., discussing Einstein's Theory of Relativity, Brush's gravitation experiments Show more16 typed and handwritten letters between John Millis and Charles F., Sr., discussing Einstein's Theory of Relativity, Brush's gravitation experiments, Millis's thoughts on gravity and magnetism, astronomy, and one about the Brush Foundation. Final letter from Millis wishes Brush happy 80th birthday. Includes paper Millis wrote for Scientific American's Einstein contest in 1921, and a letter from Millis to Scientific American regarding the papers they published as a result of the contest. Letters from 1921, 1922, 1925, 1928, 1929. Charles F. Brush, Sr., Papers Series 1: Correspondence Subseries 3: Business and Professional (1876-1931) Box 5 Folder 7 Show less