When Petermann went to the Gotha Institute part of the original plan was that he would revive the "Geographisches Jahrbuch" (Geographical Yearbook), which Heinrich Berghaus had edited from 1850 to 1852. At the suggestion of the manager Adolf Müller (1820–1880) it was decided instead to publish the monthly "Mittheilungen aus Justus Perthes Geographischer Anstalt über wichtige neue Erforschungen auf dem Gesamtgebiet der Geographie von Dr. A. Petermann" (PGM) (Communications from the Justus Perthes Geographical Institute concerning important new studies in the whole field of geography, by Dr. A. Petermann). These were to be published in 'casual issues'. Their relation to several of the Perthes atlases was plainly expounded in the preface to the first issue of 1855: