Herschel began to contribute to the 'Philosophical Transactions' in 1780, and in 1781 announced to the world his discovery of a sup posed comet, which soon turned out to be a new planet. We have not here to describe the details of this discovery, the merit of which in itself is smalL It is the method which gave rise to it on which this part of Herschel's fame must rest. Perceiving how much depended upon an exact knowledge of telescopic phenomena, and a perfect acquaintance with the effect produced by differences of instru mental construction, he commenced a regular examination of the heavens, taking the stars systematically in series, and using one tele scope throughout. If an indifferent person were by accident to pick up a manuscript out of a large number lying in a library, and were to find it on examination to be a lost classic author, ho would be entitled to praise, since it is not every one who would know what he had got bold of, even when the writing was in his hands ; but if tho same person were to make the same discovery while voluntarily engaged In the formation and classification of an immense catalogue requiring knowledge of ancient and modern languages and literature, the credit due to the discovery would be very much increased. This case is analogous with that of Herschel, who was not a mere dilettante star gazer, but a volunteer carrying on with no great pecuniary means a laboriooa and useful train of investigation.
The annooncoment of this comet or (as it turned out) planet drew Herschel immediately into the full blaze of fame; and George III. honoured his reign by immediately attaching the new astronomer to his court under the title of private astronomer to the king, with a salary of 4001. a year. Herschel fixed his residence first at Hatchet, and afterwards at Slough, near Windsor, and his abode became, as Fourier remarks, one of the remarkable spots of the civilised world. His family consisted at first of one of his brothers, and his sister, Miss Caroline Herschel, who was his coadjutor and assistant in his computations and redactions, and also actively employed in observa tion, having been, among other things, the discoverer of more than one comet. (See notice of CAROLINB HERSCHEL below.] Herschel married a widow lady, Mrs. Mary Pitt, and left one eon, whose name has long been known to the public as one of the most active and successful adherents of science that our day has produced. Sin Jona.] The deficiency of authentic information leaves us little more to say on the private life of HerscheL Ile was knighted, and received the degree of Doctor of Laws from the Univer sity of Oxford. He was soon in affluent circumstances, partly by the profits arising from the sale of his mirrors for reflecting telescopes, and partly by the jointure of his wifo, which was considerable, and he died wealthy. His death took place on the 23rd of August 1822.
Herschel's papers in the Philosophical Transactions' exhibit the unwearied activity of their author. They are in number, and range from the 70th volume, in 1780, to the 105th volume, in 1815. He also wrote a paper entitled On the Places of 145 New Double Stara,' published in the first volume of the ' Memoirs of the Astrono mical Society' in 1822.
Herschel must be remembered by the number of bodies which he added to the Solar System, making that number half as large again as he found it. Including Halley 'a comet, and the four satellites of Jupiter and five of Saturn, the number previously known was eighteen, to which he added nine, namely, Uranus and six satellites, and two satellites to Saturn. His discovery of the rotation of Saturn's ring, his measurements of the rotation of Saturn and Venue, his observa tions of the belts of the former, and his conjectural theory, derived from observation, of the rotation of Jupiter's satellites, with a large number of minor observations, prove that no one individual ever added ao much to the facts on which our knowledge of the solar system is grounded. To this we must add, that his announcement (in 1803) of the motions of binary eters round each other was accompanied by the first proof that there exist in the universe organised systems besides our own ; while his magnificent speculations on the Milky Way, the constitution of nehulm, &c. &c., first opened the road to the conception that what was called the universe might be, and in all probability is, but a detached and minute portion of that interminable series of similar fohnations which ought to bear the name. Imagination roves with ease upon such subjects; but even that daring faculty would have rejected the ideas which, alter Herschel's observations, became sober philosophy.
The instrument by which this great work was achieved was the reflecting telescope, the second reflecting surface which is found in the constructions of Newton, Gregory, and Caseegrain having been rejected, and the eye-piece applied directly to the image produced from the large mirror, which is the distinguishing feature of the Herschelian telescope. Herschel had constructed more than one such iustrument of 20 feet focal length before he attempted the enormous one of 40 feet, which he erected in the grounds of his house at Slough. This instrument was begun in 1785, and Herschel dates the completion from August 28, 1789, on which day he discovered with it the sixth satellite of Saturn.
The catalogues of double stars, nebula,, &c., and of the comparative brightness of eters, would alone constitute a title to the name of a distinguished astronomer; and the optical researches, with those on the refrangibility of heat, are highly valuable; while the papers on the power of telescopes should bo read by all who wish to understand those instruments.