As is well known, the emerging natural sciences in the seventeenth century relied to a large extent on vernacular languages. This also applied not least to the young leading medium of the new sciences, namely the scientific journal. Scientific translation in this period is therefore primarily characterised by a horizontal translation practice between vernacular languages of equal rank. Against this background, it is remarkable that some of the most important scientific journals of this period, namely the Philosophical Transactions, the Journal des sçavans and the Nouvelles Decouvertes, were translated into Latin. This article examines these translation endeavours and explores their motives, specific prerequisites and difficulties.