CHAPTER XIV.

URANUS.

Contrast between Uranus and the other great Planets-William Herschel-His Birth and Parentage- Herschel's Arrival in England-His love of LearningCommencement of his Astronomical Studies-The Construction of TelescopesReflecting Telescopes-Construction of Mirrors-The Professor of Music becomes an Astronomer-The Methodical Research-The 13th March, 1781-The Discovery of Uranus-Delicacy of Observation-Was the Object a Comet ?— The Significance of this Discovery-The Fame of Herschel-George III. and the Bath Musician-The King's Astronomer at Windsor-Caroline HerschelThe Planet Uranus-Numerical Data with reference thereto-The Four Satellites of Uranus-Their Circular Orbits-Early Observations of UranusFlamsteed's Observations-Lemonnier saw Uranus-Utility of their Measurements-The Elliptic Path-The great Problem thus Suggested.

To the present writer it has always seemed that the history of Uranus, and of the circumstances attending its discovery, form one of the most pleasing and interesting episodes in the whole history of science. We here occupy an entirely new position in the study of the solar system. All the other great planets were familiarly known to the ancients, however erroneous might be the ideas entertained in connection with them. They were conspicuous objects, and by their movements could hardly fail to attract the attention of those whose pursuits led them to observe the stars. But now we come to a great planet, whose very existence was utterly unknown to the ancients; and hence, in approaching the subject, we have first to describe the actual discovery of this object, and then to consider what we can learn as to its physical nature.

We have, in preceding pages, hal occasion to mention the revered name of William Herschel in connection with various branches of astronomy; but we have hitherto designedly postponed any more explicit reference to this extraordinary man until we have arrived at the present stage of our work. The story of Uranus,

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in its earlier stages at all events, is the story of the early career of William Herschel. It would be alike impossible and undesirable to attempt to separate them.

William Herschel, the illustrious astronomer, was born at Hanover in 1738. His father was an accomplished man, pursuing, in a somewhat humble manner, the calling of a Professor of Music. He had a family of ten children, of whom William was the fourth; and it may be noted that all the family of whom any record has been preserved inherited their father's musical talents, and became accomplished performers. Pleasing sketches have been given of this interesting family, of the unusual aptitude of William, of the long discussions on music and on philosophy, and of the little sister Caroline, destined in later years for an illustrious career. William soon learned all that his master could teach him in the ordinary branches of knowledge, and by the age of fourteen he was already a competent performer on the oboe and the viol. He was engaged in the Court orchestra at Hanover, and was also a member of the band of the Hanoverian Guards. Troublous times were soon to break up Herschel's family. The French invaded Hanover, the Hanoverian Guards were overthrown in the battle of Hastenbeck, and young William Herschel had some unpleasant experience of actual warfare. He was not wounded, but after passing the night in a ditch, he decided that he would make a change in his profession. His method of doing so is one which his biographers can scarcely be expected to defend; for, to speak plainly, he deserted, and succeeded in making his escape to England. It is stated on unquestionable authority that on Herschel's first visit to King George III. more than twenty years afterwards, his pardon was handed to him by the King himself, written out in due form.

At the age of nineteen, the young musician began to seek his fortunes by his profession in England. He met at first with very considerable hardship, but industry and skill conquered all difficulties, and by the time he was twenty-six years of age, he was thoroughly settled in England, and doing well in his profession. In the year 1766, we find Herschel occupying a position of some distinction in the musical world: he had become the

organist of the Octagon Chapel at Bath, and his time was fully employed in giving lessons to his numerous pupils, and with his preparation for concerts and for oratorios.

Notwithstanding his busy professional life, Herschel still retained that insatiable thirst for knowledge which he had when a boy. Every moment he could snatch from his musical engagements was eagerly devoted to study. In his desire to perfect his knowledge of the more abstruse parts of the theory of music, he had occasion to learn mathematics; from mathematics the transition. to optics was a natural one; and once he had commenced to study optics, he was of course brought to a knowledge of the telescope, and thence to astronomy itself.

His beginnings were made on a very modest scale. It was through a small and imperfect telescope that the great astronomer obtained his first view of the celestial glories. No doubt he had often before looked at the heavens on a clear night, and admired the thousands of stars with which it was adorned; but now, when he was able to increase his powers of vision even to a slight extent, he obtained a view which fascinated him. The stars he saw before, he now saw far more distinctly; but more than this, he found that myriads of others previously invisible were now revealed to him. Glorious, indeed, is this spectacle to any one who possesses a spark of enthusiasm for natural beauty. To Herschel this view immediately changed the whole current of his life. His success as a Professor of Music, his oratorios and his pupils, were speedily to be forgotten, and the rest of his life was to be devoted to the absorbing pursuit of one of the noblest of the sciences.

Herschel could not remain contented with the small and imperfect instrument which first interested him. Throughout his career he determined to see everything for himself in the best manner which his utmost powers could command. He at once determined to have a better instrument, and he wrote to a celebrated optician in London with a view of purchasing one. the price which the optician demanded seemed more than Herschel thought he could or ought to give. Instantly his determination was taken. A good telescope he must have, and as he could not

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buy one, he resolved to make one. It was alike fortunate, both for Herschel and for science, that circumstances impelled him to this determination. Yet, at first sight, how unpromising was the enterprise! That a music teacher, busily employed day and night, should, without previous training, expect to succeed in a task where the highest mechanical and optical skill was required, seemed indeed unlikely. But enthusiasm and genius know no insuperable difficulties. From conducting a brilliant concert in Bath, when that city was at the height of its fame, Herschel would rush home, and without even delaying to take off his lace ruffles, he would plunge into his manual labours of grinding specula and polishing lenses. No alchemist of old ever was more deeply absorbed in a project for turning lead into gold than Herschel in his determination to have a telescope. He transformed his home into a laboratory; of his drawing-room he made a carpenter's shop. Turning lathes were the furniture of his best bedroom. A telescope he must have, and as he progressed he determined, not only that he should have a good telescope, but a very good one; and as success cheered his efforts, he ultimately succeeded in constructing the greatest telescope that the world had up to that time ever seen. Though it is as an astronomer that we are concerned with Herschel, yet we must observe that, even as a telescope maker, great fame and no small degree of commercial success flowed in upon him. When the world began to ring with the glorious discoveries of Herschel, and when it was known that the Bath musician had made these discoveries with telescopes which were the work of his own hands, a demand sprang up for instruments of his construction. It is stated that he made upwards of eighty large telescopes, as well as many others of smaller size. Several of these instruments were purchased by foreign princes and potentates.* We have never heard

* Extract from "Three Cities of Russia," by C. Piazzi Smyth, Vol. ii., p. 164. "In the year 1796. It then chanced that George III., of Great Britain, was pleased to send as a present to the Empress Catharine of Russia a ten-foot reflecting telescope constructed by Sir William Herschel. Her Majesty immediately desired to try its powers, and Roumovsky was sent for from the Academy to repair to Tsarskoe-Selo where the court was at the time residing. The telescope was accordingly unpacked, and for eight long consecutive evenings the Empress employed herself ardently in observing the moon, planets, and stars; and more than this, in inquiring

that any of these illustrious personages became assiduous or celebrated astronomers, but, at all events, they seem to have paid Herschel handsomely for his skill, so that by the sale of large telescopes he was able to realise what may be regarded as a fortune in the moderate horizon of the man of science.

The instruments made by Herschel were entirely of that class which we have already described in an earlier chapter under the title of Reflecting Telescopes. These instruments were known long before Herschel's time. It was, however, left for him to discover the means by which they could be constructed of large size, while he also wrought the specula with unprecedented care. The success of a telescope of this kind mainly depends upon the accuracy with which the speculum receives that particular shape which is necessary if every ray of light is to travel to its precise destination. The methods of Herschel are not very fully known; he never published them with the same degree of detail as was subsequently given to the world by Lord Rosse and by Lassell, when they described their experience in following up the path which Herschel had indicated. It seems, however, that Herschel relied, to a very large extent, upon manual skill rather than, as his successor, did, on mechanical contrivance. It is narrated how, during the critical operation of polishing one of the great mirrors, Herschel has sat with his hands on the mirror for very many hours consecutively. On such occasions he was constantly tended by the everfaithful sister Caroline, who sat by his side to place the necessary food between his lips, and to beguile the time by reading the "Arabian Nights." What could be more appropriate reading for such an occasion than the story of Aladdin ? The wonders which Aladdin saw when he polished his lamp may well be compared with what Herschel saw when he had polished his mirror.

Up to the present point of our narrative, we have seen

into the state of astronomy in her dominions. Then it was that Roumovsky set before the Imperial view the Academy's idea of removing their observatory, detailing the necessity for, and the advantages of, such a proceeding. Graciously did the 'Semiramis of the North,' the Polar Star,' enter into all these particulars, and warmly approve of the project; but death closed her career within a few weeks after, and prevented her execution of the design."