Rossbank functioned from 1840 to 1854 as one of a chain of British Colonial Observatories which combined with European and Asian observatories in the study of terrestrial magnetism. It was established in Hobart, Tasmania, by the Governor of Van Diemen's Land, Sir John Franklin, and Captain James Clark Ross, R.N., commanding H.M. ships Erebus and Terror. The history and operation of the Rossbank Observatory is related, its instruments described, and the results discussed.Biographical notes on the Observatory staff, with lists of (...) its archives and instruments are provided. A number of previously unpublished pictures show the Observatory in use and the surviving buildings and instruments today. (shrink)