This paper examines the early years of the eighteenth-century scientific periodical Observations sur la physique, sur l'histoire naturelle et sur les arts (1771-1823, Paris), or 'Rozier's Journal', after Franois Rozier (1734-1793). Rozier's Journal is seen as a transitional and competing genre for scientific publication directed at shortcomings in the learned society press and in contemporary scientific communications. The evolution of this role is traced as the Journal emerged from the independent press between 1771 and 1773. It is argued that Rozier's Journal, limited to the sciences physiques (physical sciences), marked only a step towards the specialized periodical of the nineteenth century. The professional character of Rozier's intended audience is suggested, and Rozier's unexpectedly close ties to the scientific societies are explored. The Journal is seen to be part of both the old and the new, a unique case in the ancien rgime press.