Books Tell You Why, Inc.

An attractive first edition of Hansen's first major work incl. Addendum (Nachschrift) on pp 316 - 326 in original blue wrappers; many leaves still unopened,. Some very minor spotting on a few leaves.

The study of the mutual perturbations of Jupiter and Saturn by professor and theoretical astronomer Peter Andreas Hansen (1795-1874), director of Ernestinische Sternwarte in Seeberg, prized by the Royal Academy of Sciences in Berlin, July 8, 1930.