This unique astronomical and meteorological treatise attributed to Dionysius the Areopagite survives in only one manuscript: British Library Add. ms. 7192 (olim Rich 7192), probably of the 7th cent. Kugener here gives an edition of the Syriac text along with a French translation, which is very thoroughly annotated. In his introduction, Kugener describes the manuscript, outlines the treatise, discusses the date of composition, the possible author (including why it was attributed to Dionysius), and the style and language of the treatise. At the end of the translation, Kugener gives an index of significant Syriac words in the text, with some lexical observations. This treatise continued to be studied long after it was written, since it was used in the 13th cent. by Jacob bar Shakko in his Book of Treasures, and today it continues to be of interest especially to readers concerned with science in late antiquity.