Letter from Horace T [Tabberer] Brown, 52 Nevern Square, Kensington, to [Joseph] Larmor He is sending a few photographs of diffusion experiments [not present] describing each of four images in detail. These are early attempts, he states, and he will improve on them, but he thought that Larmor would like to see them. Diffusion through square apertures gives interesting results. 12 November 1900