By David J. Eicher
Treasures of the collection of Owen Gingerich: Essay on Comets in General by M. Dionis du Séjour, published in Paris, 1775, copy owned and annotated by Charles Messier (1730–1817), French comet hunter and deep-sky cataloguer, Owen Gingerich Collection, Harvard University, Cambridge, Massachusetts, photographed September 20, 2013.
Related blog: "A visit with Owen Gingerich, part 1"