Letter from Robert Williams Wood, Department of Physics, University of Wisconsin, 237 Langdon Street, Madison, Wisconsin, to Charles Vernon Boys It is kind of Boys to assure Wood of a good time in London, where he expects to arrive on 6 February. The Society of Arts lecture in on 14 February and he believes that the diffraction chromos should not be seen before that event. They are improved and stereoscopic. He has a new pseudoscope that gives better results. He notes a glass plate with a microscopic structure showing mock suns and halos which can be projected and discusses new sound wave photographs, illustrating his thoughts with sketches. He has kinetoscope film showing the development of a wave in motion. The letter is dated 13 January 1899, but content indicates that this is in error, for 1900. 13 January [1900]