of Edinburgh, Session 1867 - 68 . 199 
the duties of the chair with great credit to himself, and satisfaction 
to the University. 
When he was engaged at Wigan with his experiments on coal, 
he was attacked by paralysis on the 10th of July 1867, and expired 
in a few hours. Dr Richardson was elected a Fellow of this Society 
in 1866, and he was a Fellow of the Royal Society of London, a 
Member of the Royal Irish Academy, and an Associate of the 
Institution of Civil Engineers. 
The Earl of Rosse, William Parsons, a distinguished astrono- 
mer, was the eldest son of Lawrence, the second Earl, and was born 
in the city of York on the 17th June 1800. In 1818 Lord Oxman- 
town entered Trinity College, Dublin, and in the following year 
he passed into residence in Magdalene College, Oxford, where he 
took the degree of M.A. in 1822, when he was first-class in mathe- 
matics. After quitting Oxford he directed his attention to the 
construction of reflecting telescopes, and while he was occupied 
with his earliest experiments, I had the pleasure of frequent com- 
munication with him. His first scheme was to remove as much as 
possible the spherical aberration of spherical surfaces, by dividing 
the speculum into several rings, which were so placed as to have a 
common focus. The difficulty of adjusting these rings, and keep- 
ing them in their place, was so great that he abandoned the attempt, 
and set himself to the construction of telescopes with specula of a 
large size. In the execution of such instruments a thorough know- 
ledge of chemistry and mechanics was required, and the difficulties 
which he encountered at every step of the process were surmounted 
with a success greater than he could have anticipated. 
With the exception of Sir W. Herschel’s large speculum of four 
feet, the largest telescopes hitherto constructed were those of 13J, 
15, and 21 inches in diameter, by Mr Ramage of Aberdeen, and 
those of 18 inches, by Sir John Herschel. So early as 1822 Lord 
Oxmantown began to construct large specula, and he had ground 
and polished them of 15, 24, and 36 inches in diameter before he 
began the gigantic speculum of six feet, with a focal length of 56 
feet. This speculum was cast on the 13th April 1842, ground in 
1843, polished in 1844, and ready for trial in February 1845. When 
it was placed in a tube made of deal staves an inch thick, and hooped 
