the planetary system, and, fortunately for science, unable to purchase a telescope for himself, Sir William Herschel resolved, in 1774, to construct one with his own hands. With this instrument, which was a Newtonian reflector of five feet, he saw distinctly the ring of Saturn and the satellites of Jupiter. Dissatisfied with its performance, he afterwards executed two hundred specula of seven feet focal length, one hundred and fifty of ten feet, and above eighty of twenty feet! In 1781 he began a thirty feet aerial reflector, with a speculum three feet in diameter, but as it was cracked in the operation of annealing, and as another of the same size was lost in the fire from a failure in the furnace, his hopes were disappointed. In minds like his, however, disappointment is often a stimulus to higher achievements, and the double accident which befell his specula suggested, no doubt, the idea of making a still larger instrument, and of obtaining pecuniary aid for its accomplishment. He accordingly conveyed, through Sir Joseph Banks, to the King his intention to execute such a telescope, and his Majesty, with the munificent spirit of a great sovereign, instantly offered to defray the whole expense of its construction. Encouraged by this noble act of liberality, Sir William Herschel began in 1785, and completed in 1789, his gigantic telescope, forty feet in focal length, with a speculum forty-seven and a half inches in diameter! Its tube, about forty feet long and five wide, was made of iron, and the observer, suspended in a moveable seat at the mouth of it, examined, with what is called the front view, the celestial objects to which it was directed. This noble instrument, now dismantled, stood in the lawn of Sir William Herschel's house, and some of our readers may remember, like ourselves, its extraordinary aspect when visiting the great astronomer

himself, or resting in the Crown Hotel at Slough, or journeying on their way to Windsor.

It is due to the memory of George III., that the friends of science should cherish it with respect and gratitude. By enabling Sir William Herschel to construct his colossal tube, and to spend the whole of his time in applying it to the heavens, he was entitled to share in the glory of his discoveries; and we owe it to historical truth to say, that none of the sovereigns who either preceded or followed him have an equal claim on the homage of astronomers. If, in his imperial rule, he sometimes transcended the limits of constitutional government, let us remember that he left the throne more secure and glorious than he found it. If he ventured, on some occasions, to thwart the counsellors of his choice, we may find some apology for the exercise of a high prerogative in the factious character of the age, and in the acknowledged incapacity of his advisers ;-and if he lost a transatlantic empire by persisting to levy tribute from its people, he followed the advice of distinguished counsellors, and was but the instrument of a higher power in establishing a mighty nation veined with Saxon blood, and nerved with British spirit,-destined to give lessons of civilisation to the Eastern World—to afford a home to science unpatronized-to religion in persecution, and to patriotism in exile.

Stimulated by such patronage, the genius and perseverance which created instruments so transcendent in magnitude, were not likely to be baffled in their practical application. In the examination of the starry heavens, the ultimate object of his labours, Sir William Herschel exhibited the same exalted qualifications; and in a few years he rose from the level of humble life to the enjoyment of a name more glorious than that of the sages and

warriors of antiquity, and as enduring as the objects with which it will be for ever associated. Nor was it in the ardour of the spring of life that these triumphs were achieved. He had reached the middle of his appointed course before his career of discovery began, and it was in the autumn and winter of his days that he reaped the full harvest of his glory. The discovery of a new planet at the verge of the Solar System, was the first trophy of his skill, and new double and multiple stars, and new nebulæ and groups of celestial bodies, were added in hundreds to the system of the universe. The spring tide of knowledge, which was thus let in upon the human mind, continued for a while to spread its waves over Europe, but when it sank to its ebb in England, there was no other bark left upon the strand but that of the Deucalion of science, whose home had been so long upon its waters.1

When Sir William Herschel's great telescope was taken down in 1822, a telescope of 20 feet in focal length, and with an aperture of 18 inches, was erected in its place by his son, Sir John Herschel. This instrument, with three mirrors of the same size, was carried to the Cape of Good Hope, and it was with it that Sir John made those valuable observations which have added so greatly to our knowledge of Sidereal Astronomy.

About the same time, the late Mr. John Ramage, a merchant in Aberdeen, devoted much of his attention to the construction of large Newtonian reflectors. He ground and polished specula of 13, 15, and 21 inches in diameter. One of these was erected at the Royal Observa

1 For an account of the Decline of Science in England, here alluded to, we refer the reader to Sir John Herschel's Treatise on Sound, to Mr. Airy's Report on Astronomy, in the Report of the British Association for 1833, and to Mr. Babbage's interesting volume, On the Decline of Science. See also Quarterly Review, October 1830, and North British Review, vol. xiv. p. 235.

tory of Greenwich in 1820,1 with a focal length of 25 feet, and a speculum 15 inches in diameter;-another of the same size at Sir John Ross's Observatory, near Stranraer ;---and the large speculum of 21 inches, is, we believe, in the Observatory of Glasgow.2

The long interval of half a century seems to be the period of hybernation during which the telescopic mind rests from its labours, in order to acquire strength for some great achievement: Fifty years elapsed between the dwarf telescope of Newton and the large instruments of Hadley Other fifty years rolled on before Sir William Herschel constructed his magnificent telescope; and fifty years more passed away before the Earl of Rosse produced that colossal instrument which has already achieved such brilliant discoveries.

This distinguished nobleman began his experiments so early as 1828, and he ground and polished specula fifteen inches, two feet and three feet in diameter, before he commenced the Herculean attempt of executing a speculum six feet in diameter, and with a focal length of fifty feet. The speculum was cast on the 13th April 1842, ground in 1843, polished in 1844, and, in February 1845, the telescope was ready to be tried. The focal length of the speculum is fifty-four feet. It weighs four tons, and, with its supports, it is seven times as heavy as the four feet speculum of Sir William Herschel. The speculum is placed in one of the sides of a cubical wooden-box s, Fig. 6, about eight feet wide, and to the opposite end of this box is fastened the tube, which is about fifty feet long, eight

1 See Transactions of the Astronomical Society, vol. ii. p. 413.

2 A fine reflecting telescope, with a speculum two feet in diameter, and a focal length of twenty feet, has been recently constructed by Mr. Lassels, who has made with it several important discoveries within the limits of our own system.

feet in diameter in the middle, but tapering to seven at the extremities, and furnished with diaphragms 61 feet in aperture. The tube is made of deal-staves an inch thick, hooped with strong iron clamp rings, and it carries at its upper end, and in the axis of the tube, the small oval speculum A, six inches in its lesser diameter.

The telescope, as shewn in the annexed figure, is esta

FIG. 5.-Lord Rosse's Telescope from the South-East.

blished between two lofty castellated piers sixty feet high, and is raised to different altitudes by a strong chain cable B attached to the top of the tube. This cable passes over a pulley T on the frame F down to a windlass shewn at U in Fig. 6, on the ground, which is wrought by two assistants. To the frame F are attached, at x, x, chain guys fastened to the counterweights E, E. The telescope is balanced by these counterweights suspended by chains D, D, which are fixed to the sides of the tube, and pass over large iron pulleys c, c.

To the eastern pier is fixed a strong semicircle of cast