Sir James South, at all events in the later part of his career, dearly loved a fray. He commissioned a friend to bear a hostile message to a distinguished scientific contemporary. The duel never came off. Perhaps, even if it had, the results might not have been sanguinary, for it had been suggested that the two astronomers would, of course, have been placed at telescopic distances apart. But to those to whom he was attached his loyalty and devotion were unbounded; his purse and his influence were alike at their disposal. To these characteristics of South we owe the great equatorial telescope now at Dunsink Observatory.
SOUTH EQUATORIAL, DUNSINK.
The precious object-glass remained in his possession for about thirty years, until such time as the late Earl of Rosse was installed as Chancellor of the University. The Earl was one of Sir James’ warm friends, and he celebrated the occasion by presenting the great object-glass to the University of Dublin. The date of the gift is 17th February, 1863.
It was thus only a few years before Sir W. R. Hamilton’s death that Dunsink Observatory possessed a really fine objective; but it was only an objective, it was not a telescope. The engrossing labours of Sir W. R. Hamilton’s mathematical work, his advancing years, and his declining health, did not permit him to undertake the arduous labour of its erection. Sir James South found in this a sad grievance. I have heard him denounce this inaction with that vigorous language which he was accustomed to use. He had even offered to contribute liberally to the expenses of mounting, if the College authorities would put it in hands. It was not, however, until Sir W. R. Hamilton’s successor was appointed (1865) that the work was done. South lived just long enough to know that the great instrument was at last being erected. A view of the instrument, named the South Equatorial, after the donor, is shown in the adjoining illustration.
The successor of Sir William Rowan Hamilton as Andrews Professor of Astronomy was Dr. Francis Brünnow. He was a German by birth, who had distinguished himself by various astronomical researches, and by an excellent work on Practical Astronomy. He had previously occupied the Chair of Astronomy at the University of Michigan. When Brünnow came to Dunsink, his first care was the mounting of the great South Equatorial. A building was erected on the lawn, surmounted by a dome, and fitted with revolving machinery by Messrs. Grubb, who also constructed the tube and stand. A micrometer, from the Berlin firm of Messrs. Pistor & Martin, was added, and thus the South object-glass, forty years after it was made, came into actual use.
Dr. Brünnow devoted himself chiefly to the investigation of the Parallax of Stars. In this he was, indeed, following the traditions of the Observatory as laid down by Brinkley. Brünnow published two parts of his researches on this difficult subject. These papers are now regarded as a classical authority in this branch of astronomy. The pains which he took to eliminate error, and the consummate manner in which he has discussed his results, show him to have been both a skilful observer and an ingenious computer.
The fundamental equipment of the modern Observatory must include an equatorial and a meridian circle. Dunsink was now provided with the former, but there was no meridian circle. The great Ramsden instrument had become obsolete. The old transit had also seen more than half-a-century of service, and could not be relied on for accurate work. A splendid meridian circle was therefore ordered, by the liberality of the Board, from Messrs. Pistor & Martin, of Berlin. It was erected in 1872-1873, at a cost of £800. The aperture of this instrument is 6·4 inches and the length is 8 feet. The circles are divided to two-minute spaces, and read by eight microscopes, four on each side. The instrument can be reversed, and has north and south collimators. The Meridian Room and the fine instrument just described are shown in the subjoined illustration.
