James Clerk Maxwell, physicist: correspondence with Peter Guthrie Tait, Professor of Mathematics, Queens University, Belfast Three letters containing material on physics, models Maxwell has constructed, his treatise on Faraday's 'lines of force', Maxwell's correspondence with other scientists, friends, teaching and work being undertaken by students at Aberdeen University, and some humorous observations. Negative photostats of these letters (MS 980/4) and correspondence regarding their provenance and Maxwell's handwriting (MS 980/5-7) are also included. The three letters listed here were written while he was in Aberdeen to his friend of Edinburgh and Cambridge student days, Peter Guthrie Tait, then Professor of Mathematics at Queen's University, Belfast. 1856-1932