Mr. Flamsteed was also appointed the first astronomer royal at Greenwich about the same time, where he observed all the celestial phcenomena for more than 44 years ; and, as the fruits of his labours, published a catalogue of 3000 stars, with their places, to the year 1688, as also new solar tables, and a theory of the moon, according to fIorrox. Cassini, also, the first French astronomer royal, greatly distinguished himself by his numerous observations on the sun, moon and pla nets, and by the improvements he made in the elements of their motions.
In 1719, Mr. Flamsteed was succeeded by Dr. Halley, the friend of Newton, and a man of the first eminence in all - classes of literature and science, who had been sent, at the early age of 21, to the island of St. Helena, to observe the southern stars, a catalogue of which he published in 1729 ; and a few years after wards he gave to the public his " Synop sis Astronomix Cometicx," in which he ventured to predict the return of a comet in 1758 or 1759.
On the death of Dr. IIalley, in 1742, he was succeeded by Dr. Bradley, who has rendered himself highly celebrated by two of the finest discoveries that have ever been made in astronomy, the aber ration of light, and the nutation of the earth's axis. Among other things, he al so formed new and accurate tables of the motions of Jupiter's satellites, as well as the most correct table of refractions yet extant. Also, with a large transit instru ment, and a new mural quadrant of eight feet radius, constructed by Bird, in 1750, he made an immense number of observa tions, for settling the places of all the stars in the British catalogue, together with nearly 150 places of the moon, the greater part of which he compared with Mayer's tables.
Dr. Bradley was succeeded in 1762, in his office of astronomer royal, by Mr.
Bliss, but who, being in a declining state of health, died in 1765, and was succeed ed by Nevil Maskelyne, D. D., the pre sent astronomer royal, who has rendered considerable services to this science, by his publication of the " Nautical Alma. nac," the "Requisite Tables," &c. ; and more particularly by the great assiduity and zeal he has displayed in bringing the lunar method of determining the longi tude at sea into general practice.
Such was the state of astronomy, when Dr. Herschell, by augmenting the powers of telescopes beyond the most sanguine expectations, opened a scene altogether unlooked for. By this indefatigable ob server, we are made acquainted with a new primary planet belonging to our sys tem, called the Georgium Sidus, attended by six satellites, which he discovered on the 13th of March, 1781, and which, be ing at twice the distance of Saturn from the sun, has doubled the bounds formerly assigned to the solar system. We are also indebted to him for a variety of observa tions on several other interesting astrono mical subjects ; such as the discovery of two additional satellites to Saturn, of which the number is now seven ; a new method of measuring the lunar mountains; the ro tation of the planets on their axis ; on the parallax of the fixed stars ; catalogues of double, triple stars, &c. ; of nebula ; and of the proper motion of the sun and so. lar system ; the accounts of which, toge ther with many other valuable papers, lie has communicated, from time to time, in different parts of the Philosophical Trans actions. A new planet has been disco vered by M. Piazzi, of Palermo, between Mars and Jupiter, to which has been given the name of Ceres Perdinandia ; another by Dr. Olbers ; a third and a fourth have also been discovered, which we shall briefly notice farther on.