Letter to Edward Clark Streeter, March 31, 1919
Letter to Herbert Albert Laurens Fisher, April 2, 1919
Letter to John Guppy, April 5, 1919
Letter to Champe Carter McCulloch, April 9, 1919
Letter to G. H. (?) McLean, April 14, 1919
Letter to John George Adami, April 25, 1919
Letter to John Young Walker MacAlister, April 26, 1919
Letter to Thomas Stephen Cullen, April 29, 1919
Letter to Karl Friedrich Wenckebach, May 1, 1919
Letter to Geoffrey Keynes, May 1, 1919