ROEBUCK, Joig, an eminent physician, and a great benefactor to Scotland, was born in Sheffield, in 1718. Having completed his clerical education under Dr. Dod dridge of Northampton, he studied medicine and chemis try at Edinburgh, from whence he went to Leyden, and took his degree of M. D. in 1743.
After his return from the continent, he settled as a physician at Birmingham, where the rising science of chemistry attracted his particular attention. In a small laboratory which he fitted up he spent all his leisure hours ; and one of his first discoveries was a new me thod of refining gold and silver, and of collecting the smaller particles of these precious metals, which had previously been lost. He discovered an improved me thod of making sublimated hartshorn, and other articles of great use. Having associated himself with Mr. Samuel Garbut of Birmingham, they established a labo ratory on a large scale, and after they had discovered a method of making sulphuric acid in vessels of lead in place of glass, they established, in 1749, the manufnc ture of sulphuric acid, which still exists at Preston Pans, about nine miles to the east of Edinburgh. Scotland now became the principal residence of our author, and he here conceived the great project of establishing an extensive manufactory of iron ; and having fixed upon Carron as the most appropriate site for it, he obtained plans, Cc. of the machinery from Mr. Smeaton. The preparations for that great national establishment were completed in 1757. (See our article CARRON Woacs, for an account of the establishment.) When this work was fairly under the routine of its ordinary managers, Dr. Roebuck took a lease of the Duke of Hamilton's extensive coal and salt works at Borrowstounness; but after many years of labour and industry, the speculation turned out a most ruinous one, after he had sunk in it his own and his wife's fortune, as well as numerous sums borrowed from his relations and friends. After withdrawing his capital from the refining work at Birmingham, the vitriol work at Preston Pans, the iron works at Carron, and parted with his interest in the project of improving the steam engine in which he had become a partner with Mr. Watt, he was allowed by his creditors to draw from his colliery a moderate annual maintenance for himself and his family during his life.
These disasters produced a great effect upon his spirits. Ile was attacked with a complaint which re quired a dangerous surgical operation, which he sup ported with his usual resolution. The effect of it, however, never left him, and after being a few days confined to bed, he died on the 17th July, 1799, in the 76th year of his age.
Dr. Roebuck was a member of the Philosophical Society of Edinburgh, and became a member of the Royal Society at its establishment in 1783. He read
to the Royal Society of Edinburgh the following papers: 1. Observations on the ripening and filling of corn. Read January 5th, 1784. Ile found that corn ripened at a temperature of 43°, and lie advises farmers to be cautious in cutting down their unripe corn on the false supposition that in a cold autumn it could fill no more.
2. Account of certain phenomena observed in the air vault of the furnaces of the Devon iron works, together with some practical the management of blast furnaces. In a letter to Sir James Hall, Bart. Read July 2d, 1798. Edinburgh Transactions, Vol. V. p. 31. See also the article BLOWING, in this work.
Dr. Roebuck was elected a fellow of the Royal Society of London on the 12th July, 1764, and he printed in the Philosophical Transactions the following papers: 1. A comparison of the heat of London and Edinburgh•. Philosophical Transactions, 1775, Vol. LXV. p. 459.
2. Experiments in ignited bodies. Philosophical Transactions, 1776, Vol. LXVI. p. 509.
ROEMER, 01.411s, a celebrated Danish astronomer, was born at Aarhusen in Jutland, in 1644. Ile studied mathematics at the university of Copenhagen, and such had been his progress, that Picard and Cassini employed him in 1671, and on their return from their astronomical observations, they carried him along with them to Paris, where he was received as a member of the Royal Aca demy of Sciences in 1672. In this capital he resided ten years, during which time he made his great disco very of the velocity of light, of which we have given an account in our articles A StRONONIV and OPTICS. Here he also discovered the application of the epicycloidal curve to the teeth of wheels, as described in our article on Mcclinrcies.
In 1681, Christian V. appointed him professor of as tronomy at Copenhagen, and employed him in reforming the coin and the architecture of the kingdom, in regulating the weights and measures, and in surveying the roads.
In 1687, he travelled at the king's desire through England, France, Holland and Germany, to collect use ful information, and on his return in 1688 he was made counsellor of the chancellerie, and in 1693 assessor of the supreme tribunal of justice. From Frederick IV. he received additional dignities. In 1705 he appointed him burgomaster of Copenhagen, and in 1706 he gave him the dignity of counsellor of state.
When Roemer was preparing to publish the results of his observations, he was siezed with an illness which carried him off on the 19th September, 1710, in the 66th year of his age. Most of his observations, however, were published by his pupil, Peter Horrcbow, professor of astronomy at Copenhagen, in his Basis ?Istronomic. An account of Roemer's method of graduating astronomical instruments will be found in our article GRADUATION.