William Parsons

From A Compendium of Irish Biography, 1878

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Parsons, William, 3rd Earl of Rosse, astronomer, son of preceding, was born at York, 17th June 1800. He was educated at Dublin and also at Oxford, where he took high honours, especially in mathematics. He represented the King's County in Parliament from 1821 to 1834, and succeeded his father in the earldom in 1841. In 1845 he was elected a representative peer of Ireland. He filled the distinguished post of Chancellor of the University of Dublin for many years. Although a strong Conservative, he latterly took little part in politics, and his name was unheard in the debates during the whole of the stirring period that embraced the Catholic Emancipation and Reform movements.

The charms of science gradually weaned him from all pursuits that interfered with its cultivation. During the discussion of the Reform Bill he was occupied with the construction of his first great telescope, the speculum of which had a diameter of three feet, being larger than that of any previous instrument. Its success was so complete, that he was emboldened to construct one with a speculum double the diameter. Every step in the process, necessitating a combination of scientific knowledge and mechanical skill, had to be pioneered by experiments, and success was won at the cost of many and harassing failures. The gigantic speculum was at length turned out without warp or flaw. It was mounted on a telescope fifty-two feet in length. The machinery required to move such a ponderous instrument taxed all Lord Rosse's mechanical genius. The task was completed in 1845, after seventeen years' labour, at an outlay of upwards of £20,000. The sphere of observation was immensely widened by such a powerful instrument — nebulae were resolved into stars, and new nebulous mist was revealed to the observation.

The Annual Register says: "The value of the instrument was not only seen in the enlarged power it gave to astronomers, but it opened the way to other instruments of equal power being constructed. .. The scientific fame of the late Earl of Rosse will rest rather upon the mechanical than upon the observational branch of astronomy... Considering the immense power of the great telescope, the results that have emanated from it, although startling in their nature, have been small in extent. Drawings of the most remarkable nebulae, a few sketches of part of the lunar surface, and lastly, a large drawing of the nebula in Orion, are the chief fruits that are publicly known to have been gathered from it... The published writings of the late Earl comprise accurate descriptions of his telescopes and the modes by which they were constructed, together with such drawings and observations as were made with them." Lord Rosse was President of the Royal Society from 1849 to 1854, and served on several Royal Commissions relating to literature, education, and science. He was a member of several home and foreign scientific bodies. He was a genial companion and a liberal landlord. He died 31st October 1867, aged 67, and was interred in the church of St. Brandon, Parsonstown.


7. Annual Register. London, 1756-1877.

54. Burke, Sir Bernard: Peerage and Baronetage.

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