11 



After leaving Oxford he travelled extensively, with a sextant, chronometer, 

 and telescope as his inseparable companions. While at Naples in 1820 

 he met Sir William Drummond, some of whose wild inferences from the 

 Dendera Zodiac he showed to be inconsistent with sound astronomy. Sir 

 William replied that these objections were based on the inaccuracy of the 

 existing drawings ; and Mr. Cooper met that by going to Egypt, securing 

 the services of an accomplished Italian artist, and bringing home correct 

 plans of the Dendera ceiling, which, with many other drawings, he printed 

 for private distribution under the title * Egyptian Scenery.' He thence 

 visited Persia, Turkey, Germany, and Scandinavia as far as the North 

 Cape, accumulating a great mass of observations of latitude and longitude, 

 which unfortunately remain unpublished. Shortly after his return to 

 Ireland the death of his uncle placed him in possession of a large estate, 

 and enabled him to carry out on a great scale the plan which he had formed 

 of determining some portion of the small stars which were in general 

 neglected by the great observatories. In the year 1831 he purchased, from 

 Cauchoix of Paris, an object-glass of 13*3 inches aperture and 25 feet 

 focus, the largest then existing, which in 1834 was mounted with perfect 

 success at his magnificent mansion of Markree, on an equatorial constructed 

 by Mr. Grubb of Dublin. It is of cast iron (the first application of that 

 material to astronomical instruments), and stands in the open air, encircled 

 by the buildings of a first-rate observatory, which contain, among other 

 chefs-cP ceuvres^ a fine meridian- circle by Ertel, with eight microscopes, and 

 an 8-inch object-glass. These instruments were at once applied to active 

 work, in which he had a most able cooperator, his first assistant, Mr. A. 

 Graham ; and the Memoirs of the Royal Astronomical Society and of the 

 Royal Irish Academy (of both which he was a member) bear ample 

 testimony of their diligence. One result of their labours was the discovery 

 of the planet Metis ; but his greatest work is his ' Catalogue of Ecliptic 

 Stars.' This (which was published by aid from the Government grant 

 placed at the disposal of the Royal Society, and which the Royal Irish 

 Academy honoured with their Cunningham Medal) contains upwards of 

 60,000 stars down to the 12th magnitude, of which very few had been 

 previously observed. The places are reduced to 1850, and though only 

 approximate, possess a sufficient degree of precision for the use to which 

 they were destined. Their probable error is +2"'6, both in right ascen- 

 sion and in declination. The value of this Catalogue to future astronomers 

 can scarcely be overrated, for many facts tend to show that much is to be 

 learned by studying these minute stars. As an instance, it may be stated 

 that fifty stars of his own Catalogue and twenty-seven of others' were 

 found to have disappeared during the progress of the observations. Many 

 of these, no doubt, are variable ; many probably are unknown planets ; 

 some perhaps have great proper motion. But when shall we have such a 

 survey of the whole sky as that of this comparatively small zone ! 



He promised a fifth volume, the materials for which are nearly complete. 



