the solar system. It was thought complete for nearly a century.
In England, the remarkable discoveries of Bradley (1727–62) had been in the field of practical astronomy, and his example had set the key-note for further researches. France was just about beginning the brilliant period of her discoveries in mathematical astronomy, and had no observatory devoted to investigations like Herschel's, with the possible exception of Darquier's and Flaugergues'. The observatories of Schroeter and Von Hahn, in Germany, were not yet active. The field which Herschel was created to fill was vacant, the whole world over. It was especially so in England. The Royal Observatory at Greenwich, under Maskelyne, a skilful observer, whose work was mostly confined to meridian observations, was no rival to a private observatory like Herschel's. The private observatories themselves were but small affairs; those of the king, at Kew, of Dr. Wilson, at Glasgow, of Mr. Aubert, at Loampit Hill, of the Count von Bruhl, in London,
