Correspondence and papers concerning instructions, magnetic instruments and photographic techniques. The papers include J. Glaisher's report to the Astronomer Royal on examining the magnetic instruments at the Greenwich Observatory; adjustments to vertical force magnets and compasses; sketches of new mountings for dipping needles; discrepancies of dip; alterations of instruments; trials of dipping needles; papers by J.V. Lamont on the form of magnets (one in English, one in German) and determining the value of scale divisions for magnetic instruments; J.A. Brown's magnetic observations in India; papers on photographic stores needed for Greenwich; methods and samples of reproduction of photographs of barometer readings; a drawing of a new naptha box; and a paper and drawing on photo-zincography by H. James. The correspondents include C. Brooke, E. Sabine, B. Stewart, M. Faraday, C. Hansteen, J. Washington, M.J. Johnson and H. James.