London: Longman, Brown, Green, and Longmans, 1855 and 1858. Hardcover. Francois Arago (1786-1853) was an important French astronomer, physicist, and mathematician, who was also a politician for republican causes. For some years before his death, Arago spent much time revising his large collection of manuscripts with a view toward their definitive publication. This work mainly consists of the course of Lectures on Astronomy which he delivered annually at the Observatory of Paris over eighteen years. Each of the volumes is organized into sections that the author calls books with several chapters on the subject of that book, resulting in a comprehensive discourse on astronomy and related fields. The text is accompanied by numerous plates and hundreds of wood engravings. Bound in original green cloth bindings. Volume I has been rebacked. Gilt author, title, and volume number to spine. Corners bumped but very good. Interior pages and plates are also in very good condition. A very handsome set of this significant work. Volume I: 707 pages; Volume II: 846 pages including index. This set may require an extra shipping fee. SCI/07415. Very Good.