Catom Catom Scientific Antiques has been buying and selling antique scientific instruments for many years, specialising in slide rules and calculating instruments, microscopes and microscope slides. A member of the Oughtred Society, the international organisation dedicated to the history and collection of slide rules, and the UK Slide Rule Circle. Has also acted as a consultant for Miller's and Lyle's Antique Guides, and a number of UK auction houses. email: charles.tomlinson@lineone.net