Birr telescope c 1845
The Great Telescope about 1845 with the castle in the background

Surviving diaries and accounts of activities in Offaly (King’s County) in the nineteenth century are uncommon and because of this all need to be catalogued and evaluated. Diaries of travel writers, correspondence and memoirs can all throw light on activities of that time. One such source recently acquired by the Offaly Historical and Archaeological Society for its library is Reminiscences and Letters of Sir Robert Ball edited by his son W. Valentine Ball and published in 1915. It sets the scene for the intellectual milieu in which the children of the third earl of Rosse grew up and provides further information on the construction of the great telescope. Recently, a history of the building of the telescope was reprinted by Cambridge University as a cheap paperback while the Royal Society hosted a lecture on the ‘Leviathan of Parsonstown’ now available as a podcast.

R.S. Ball astronomer - Copy

Robert Stawell Ball was born in Dublin in 1840 and died at Cambridge in 1913. His father, Robert Ball, was a distinguished natural historian and zoologist and imbibed fully the Victorian passion for classification. Like the Parsons family so too with the Ball family, both contributed much to natural science and are now celebrated as great scientific families in Ireland. During his time at Birr R. S Ball lived at Cumberland House in Duke (now Emmet) Square. After a distinguished career at Trinity (from 1857) he accepted a post teaching the three younger sons of the astronomer third earl of Rosse, who was chancellor of the University of Dublin (T.C.D.) from 1862 until his death in 1867. It was Rosse who recommended Ball for a professorship at the Royal College of Science, Dublin in 1867, thus bringing to an end his sojourn at Birr. The third earl died in the same year. Further details of several references to distinguished men of science found in Ball’s chapter on Birr (pp 62-79) can be further explored in Irish Innovators in Science and Technology edited by Charles Mollan, William Davis and Brendan Finucane (RIA, Dublin, 2002). Further information, but curiously no reference to Ball’s memoir will be found in Patrick Moore, The Astronomy of Birr Castle (London 1971). See also Ball’s Great Astronomers. Ball was knighted in 1886 and awarded an honorary doctorate in 1892. He died at the Cambridge University Observatory in 1913. For more see DIB, 1, pp 252–3, entry by Anne Dolan. See also see Trevor Weekes, ‘Origins of the third earl’s interest in astronomy’ in Charles Mollan (ed.), William Parsons, 3rd earl of Rosse: astronomy and the castle in nineteenth-century Ireland (Manchester, 2014), pp 30–43, 43; entry by W. Garrett Scaife for William Parsons in DIB, 7, 1109-1110.


W. Valentine Ball writes of his father –

After my father left Trinity College, the next few years of his life were spent at Parsonstown, where he was tutor to Lord Rosse’s sons. His experiences during this period are thus recorded by himself:

I do not think it had ever occurred to me to embark upon an astronomical career until November 8th, 1865, when I received a letter from Dr. Johnstone Stoney. It conveyed the following message: “Would it be agreeable to you to act as tutor to Lord Rosse’s sons at Parsonstown?” . . When it reached me, Lord Rosse, who had been President of the Royal Society, was one of the most prominent men of science in the kingdom. His great telescope was then, as indeed it still is, unrivalled in dimensions. I saw in this letter an opportunity for studying astronomy under the very best auspices . ..

Birr Castle

Let me describe the scenes and conditions amongst which my life for the next two interesting years was to be passed. The residence of the Earl of Rosse is at Birr Castle, in King’s County, about eighty miles from Dublin. Birr Castle is situated at the little town, which was then officially known as “Parsonstown,” but to the inhabitants as “Birr.” Quite recently I believe the official designation has been abandoned, and the Post Office only recognizes “Birr.” Birr Castle is a noble building of modern erection, surrounded by a moat. It is situated in a beautiful park, through which two pretty rivers flow, and these unite in a single stream before they leave. The park has also a large artificial lake, ingeniously constructed by Lord Rosse himself, which is the perennial home of innumerable wild duck. Several instances of Lord Rosse’s consummate mechanical skill are to be found about the grounds. Visitors used to stand gazing in wonder on a water-wheel which, being turned by the waters from the lake, raised water from a drainage system connected with low-lying lands around. A suspension bridge was thrown across the river close to the castle.

The outstanding feature of Birr Castle, by which it will be forever famous in the annals of science, is the mighty telescope. Between the lake and the castle are two great walls, which are now somewhat overgrown with ivy. I have been told that visitors entering the gates of the park for the first time have driven up to these walls ‘In the belief that they were approaching the castle itself, which is not visible from the park gates. Between these two walls there swings a tube sixty feet long and six feet in diameter – a tube large enough to be the funnel of a good size steamship. At the lower end of this tube is the mighty mirror or speculum Lord Rosse’s telescope is what is known as a “reflecting telescope “ – a reflecting telescope of the Newtonian type. The instrument is raised by means of a winch, which is place towards the north, and the observers who are to use the telescope have to make their way to the galleries. It is characteristic of this type of telescope that the eye-piece is at the top of the tube, not, as in the refracting instruments; at the bottom four men had to be summoned to assist the observer. One stood at the winch to raise or lower, another at the lower end of the instrument to give it an eastward or westward motion as directed by the astronomer, while the third had to be read’ to move the gallery in and out, in order to keep the observer conveniently placed with regard to the eye-piece. It was the duty of the fourth to look after the lamps and attend to minor matters.

William Parsons 3rd Earl Of Rosse (2)
Foley’s sculpture of the third earl was unveiled in 1876. Courtesy of Birr Castle Arcives and the earl of Rosse.

Lord Rosse not only designed the great instrument, but actually constructed it. At the back of the castle he had ex¬tensive workshops, where a capable smith named Coghlan and numerous assistants carried out the work under the direction of the Earl himself. It was he who devised methods for getting over the innumerable difficulties involved in casting, grinding, and polishing the great speculum, which weighed over three tons.* He had many failures before he achieved success; and the precepts which he laid down have been followed by all who have since made great reflecting telescopes. To illustrate the thoroughness of his methods, let me recall one detail which I heard from his own lips. In the final polishing of the mirror, rouge was the material employed. When he commenced operations he found that the rouge of commerce was not satisfactory. He therefore investigated the subject, and eventually discovered the way to make good rouge. His method was afterwards adopted in the manufacture of the rouge which is used by the great silversmiths in London.

When I went to Parsonstown, in 1865, Lord Rosse was advanced in years. He no longer took an active part in the work of observation, but he evinced a lively interest in all.

2 The third earl of Rosse (died 1867) (1)
The third earl died in 1867

Famous Astronomers

Lord Oxmantown, Lord Rosse’s eldest son, was not one of my pupils. They were his three younger brothers, who are now the Hon. and Rev. Randal Parsons, the Hon. R. C. Parsons – a well-known engineer – while the youngest is the Hon. Sir C. A. Parsons. It has always been a great satisfaction to me to remember that I had the great honour of instilling the elements of algebra and Euclid into the mind of the famous man who has revolutionized the use of steam by his invention of the steam turbine. It would seem that he inherited his father’s brilliant mechanical genius, with an enormous increase in its effect on the world.

The two years I spent at Parsonstown were full of interest. Ever since the erection of the great telescope, Lord Rosse had had an astronomer in charge of it. They were five in number, but I only propose to mention three. The first of these was my friend, Dr. George Johnstone Stoney, whom I have already mentioned. He was in Lord Rosse’s Observatory in the early days of the great telescope. He did much excellent work, and laid the foundation of a scientific reputation, which was greatly enhanced by his subsequent labours. He left Lord Rosse to become Professor of Natural Philosophy at Queen’s College, and was subsequently appointed to succeed my father in Dublin as secretary of the Queen’s University. It was then that my friendship with him began, and it lasted until his lamented death in 1911. Although he retired from every official position some time before his death, he devoted his well-earned leisure to strenuous labour in many branches of science. He often found the hours of the day too short for all he wanted to do. Of the many scientific people who work at electricity, physics, acoustics, spectroscopy, and microscopy, there are few who would not gladly acknowledge that Dr. Stoney had often been their teacher.

It was he who began the great work of observing nebulae with the big telescope. Nebula was at that time objects of special interest. At the beginning of the century, Sir William Herschel had completed his famous survey of such nebulous objects as were visible in the northern sky, while Sir John Herschel in his expedition to the Cape of Good Hope, had completed the work which had been begun by his father. It was left to the Earl of Rosse to start from the point which these investigators had already reached. His telescope was much more powerful than those which the Herschels had used. Indeed its optical and mechanical arrangements were as perfect as was possible in an instrument of this description. On the other hand, it must be remembered that Birr Castle is not an ideal place for an observatory. It is near to the Bog of Allen. Consequently, the skies were frequently overhung with clouds, to the distraction of the astronomer. Even Herschel himself, in his observatory near Windsor, had found that not more than a hundred hours in the whole year were adapted for the purposes of the highest class of astronomical investigation.

Felling trees was a favourite amusement of Lord Rosse

For, as already explained, I was both tutor and astronomer. The morning was spent with my pupils in the castle. Hours of study over, we indulged in certain rather strenuous forms of relaxation. Felling trees was a favourite amusement of Lord Rosse, and we frequently spent an afternoon so employed. If one desired to fish, there were great pike to be caught in the lake. But the large workshops were my chief resort during the hours of leisure. I managed to construct a six-inch reflector, having learnt under Lord Rosse’s guidance the uses of the screw-cutting lathe and other metal¬working tools. Nor did my young pupils confine their energies to the work of the classroom. In those days there was a small workshop just off the library at Birr Castle. This was the constant resort of my youngest pupil, the Hon. Charles Parsons. In this little den he was always making all sorts of machines. I remember two of his early contrivances. One of them was an air cane, and the other a sounding machine, which he afterwards used with success in his father’s lake. .


Lord Oxmantown was also an assiduous observer. Many a night did we spend together at the great telescope. Astronomy was just then beginning to quicken with new life under the great impulse that had been given to it by recent spectroscopic discoveries. .

The visitors’ book at the Parsonstown Observatory contains the names of many great astronomers, both native and foreign. Amongst them I can recall those of Dr. Romney Robinson, who had been intimately associated with Lord Rosse from the first, the late Sir George Stokes, the Astronomer Royal, Sir George Airy, Sir John Herschel, General Sabine, and many more too numerous to mention. I should add that these visitors had been there before my time, for by 1865, when I was in charge, the novelty of the great instrument had to some extent died away.

Lord Rosse always went to London for the season, and as he took me with him I had opportunities of becoming acquainted with many distinguished men of science. On one occasion we paid a visit to Wheatstone, who was famous not only in relation to the electric telegraph, but also as the inventor of the concertina and the stereoscope. Wheatstone showed us the original apparatus, which he had used in perfecting these inventions. Amongst other curious things he showed us what, for want of a better phrase, I will describe as a negative stereoscope. If one looked at a face through this instrument, instead of appearing to stand out in relief, it appeared to be hollow – just as if one were looking into a mould which had been taken from the face. On another occasion Lord Oxmantown and I went to spend a day with Mr. Babbage, the inventor of the calculating machine. . . Lord Rosse also took me to see Sir William Huggins, K.C.B. the late President of the Royal Society.

Among the visitors at Birr I should have mentioned Dr. Brunnow, who was appointed Astronomer Royal of Ireland in succession to Sir William Rowan Hamilton, who died in 1865. . .

I will conclude what I have to say about my sojourn with Lord Rosse by stating that shortly after I went to the Royal College of Science, Lord Rosse fell into bad health, and after a severe operation, from which he never rallied, he died on October 30th, 1867.