1 There is a certain incongruity, accordingly, among the symbols of the primary planets. Mercury is symbolised by his caduceus, Venus by her looking-glass (I suppose), Mars by his spear and shield, Jupiter by his throne, Saturn by his sickle; and again, when we pass to the symbols assigned to the planets discovered in the present century, we find Neptune symbolized by his trident, Vesta by her altar, Ceres by her sickle, Minerva by a sword, and Juno by a star-tipped sceptre. Uranus alone is represented by a symbol which has no relation to his position among the deities of mythology.
2 Both these names are found among the asteroids, the fifth of these bodies (in order of discovery) being called Astraea, the eighty-ninth being named after the great mother of gods and goddesses.
Herschel himself proposed another name. As Galileo had called the satellites of Jupiter the Medicean planets, while French astronomers proposed to call the spots on the sun the Bourbonian stars, so Herschel, grateful for the kindness which he had received at the hands of George III., proposed that the new planet should be called Georgium Sidus. On account of the interest attaching to all Herschel's remarks respecting his discovery, I quote in full the letter in which he submitted this proposition to Sir Joseph Banks, then the President of the Royal Society. ' By the observations of the most eminent astronomers in Europe,' he remarks, 'it appears that the new star, which I had the honour of pointing-out to them in March 1781, is a primary planet of our solar system. A body so nearly related to us by its similar condition and situation in the unbounded expanse of the starry heavens, must often be the subject of the conversation, not only of astronomers, but of every lover of science in general. This consideration, then, makes it necessary to give it a name, whereby it may be distinguished from the rest of the planets and fixed stars. In the fabulous ages of ancient times, the appellations of Mercury, Venus, Mars, Jupiter, and Saturn, were given to the planets, as being their principal heroes and divinities. In the present more philosophical era, it would be hardly allowable to have recourse to the same method, and call on Juno, Pallas, Apollo, or Minerva, for a name to our new planet. The first consideration in any particular event or remarkable incident seems to be its chronology; if, in any future age it should be asked when this last-found planet was discovered, it would be very satisfactory to say, "In the reign of George III." As a philosopher, then, the name of Georgium Sidus presents itself to me as an appellation which will conveniently convey the information of the time and country where and when it was brought to view. But as a subject of the best of kings, who is the liberal protector of every art and science; as a native of the country from whence this illustrious family was called to the British throne; as a member of that society which flourishes by the distinguished liberality of its royal patron; and last of all as a person now more immediately under the protection of this excellent monarch, and owing everything to his unlimited bounty, I cannot but wish to take this opportunity of expressing my gratitude by giving the name of Georgium Sidus-
'Georgium sidus - jam nunc assuesce vocari,' to a star which, with respect to us, first began to shine under his auspicious reign.' Herschel concludes by remarking that, by addressing this letter to the President of the Royal Society, he takes the most effectual method of communicating the proposed name to the literati of Europe, which he hopes 'they will receive with pleasure.'
Herschel's proposition found little favour, however, among Continental astronomers. Indeed it is somewhat singular that for some time two names came into general use - one in Great Britain and the other on the Continent, neither being the name eventually adopted for the planet. In books published in England for more than a quarter of a century after the discovery of Uranus we find the planet called either the Georgium Sidus, or the Georgian. For a shorter season the planet was called on the Continent either the Herschelian planet, or simply Herschel. Many years elapsed before the present usage was definitely established.
In considering Herschel's telescopic study of the planet, we must remember that, owing to the enormous length of time occupied by Uranus in circling round his orbit, the astronomer labours under a difficulty distinct in character from the difficulties which have already been considered. As Jupiter and Saturn circle on their wide orbits they exhibit to us-the former in the course of eleven years, the latter in the course of twenty-nine and a half years-all those varying presentations which correspond to the seasons of these planets. Jupiter, indeed, owing to the uprightness of his axis (with reference to his path) presents but slight changes. But Saturn's globe is at one time bowed towards us, so that a large portion of his north polar regions can be seen, and anon (fifteen years later) is so bowed, that a large portion of his southern polar regions can be seen; while between these epochs we see the globe of Saturn so posed that both poles are on the edge of his disc, and then only does the shape of his disc indicate truly the compression or polar flattening of the planet.
But although similar changes occur in the case of Uranus, they occupy no less than eighty-four years in running through their cycle, or forty-two years in completing a half cycle - during which, necessarily, all possible presentations of the planet are exhibited. Now it is commonly recognised among telescopists that the observing time of an astronomer's life - that is, the period during which he retains not merely his full skill, but the energy necessary for difficult researches -continues but about twenty-five years at the outside. So that few astronomers can hope to study Uranus in all his presentations, as they can study Mars, or Jupiter, or Saturn.