Henrici, Olaus Magnus Friedrich Erdmann Letters to Pearson regarding: <i>The Common Sense of the Exact Sciences</i>; testimonials; Pearson's work on shafting; Henrici's course at the City & Guilds of London Institute of Technical Education; work on error curves; debates over the constitution of the University of London; the Hatchet Planimeter; the Brunsviga calculating machine; regarding papers to be presented to the Royal Society; Pearson's proposed book on Graphics; Chisholm's phD work in Göttinger; and the details of mathematics degrees offered at the Institute of Technical Education. Apr 1885