The spectroscopic binary capella ; The variable velocities of epsílon librae, h Draconis, lambda Andromedae, epsílon Ursae minoris and omega Draconis ; The variable velocity of alfa Ursae minoris in the line of sight ; The wave-length of the green coronal line, and other data resulting from an attempt to determine the law of rotation of the solar corona - Campbell, William Wallace, 1862-1938 (The university of Chicago Press, 1899)