... a man of studious bent and author of archaeological studies of local interest ...

... financial secretary to the duke of Leinster ... later appointed keeper of the house of lords in Ireland, and owned several houses on Harcourt Street.

... as a student in Trinity College there was nothing accomplished by Joly that has not been accomplished by many a man who subsequently remained without further distinctions through life. He took a mathematical scholarship - by no means on specially brilliant marks - and finally won a mathematical studentship, but, again, without the distinction of the "Large" gold medal. His second subject at this examination was Experimental Science.

The possibility of attaining to the Fellowship of his own College induced him to pursue the mathematical and mathematical-physics courses required for the mathematical side of this test. The severity of this competition is intensified by the extraordinary arrangement permitting candidates in mathematics and classics to compete against each other; the successful candidate being the winner of highest marks, where subjects, papers, examiners are different. For this ordeal it is not uncommon for men to read for five or seven years; not, perhaps, acquiring fresh wisdom after the first two or three years' reading, though gradually becoming more proficient in the art of scoring.

Year after year Joly fell short of success. Year after year he read Dante and other masters of literature, and, led away by the facile charms of literary studies, he plunged, forgetful of everything else, into the real or unreal world of poetry and romance. It was at this period that my own more intimate friendship with him commenced. Besides the tie of relationship, we had many tastes in common. In the course of our endless discussions and speculations there was revealed to me a mind both keen, critical, and honest; a nature undemonstrative, sincere, and deeply affectionate. It was not till 1894 that Joly was successful in his efforts to gain Fellowship.

The old House commands from the south windows an extensive view. The panorama of the Dublin Hills - the rounded granite hills of Leinster - rising one beyond the other, invite the imagination into the furthest distance. Between lies a broad and noble valley containing in the near distance the lawns and woods of Phoenix Park, and to the east the City of Dublin. The pastoral element predominates, however, and, seen from this view-point, Dublin might appear to be a city girt with peaceful lawns and forest trees. Further yet, beyond the "towers, domes, citadels," the Bay of Dublin stretches to the horizon. A more varied sweep of mountains, forest, city and sea it would be hard to find. From the south window of the study an observer lifting his eyes can, at a glance, review it all. Around the house is the fruit garden and shrubbery, planted by John Brinkley and Robert Ball, and the old-fashioned box-trimmed flower garden merging into the orchard. Tall trees line the shady walk leading to the gate in the wall where suddenly is revealed to you, across steeply sloping fields, the same majestic panorama of mountains and woods seen from the study window.

In the summer of the year 1899, Sir Howard Grubb proposed that a Joint Committee should be appointed by the Councils of the Royal Dublin Society and the Royal Irish Academy to consider the feasibility of fitting out an expedition to observe the Total Solar Eclipse of 1900, May 28th. As many members of the Societies signified their intention of witnessing the eclipse, it seemed probable that the number of those joining the expedition would be sufficiently large to justify the chartering of a steamer, and it was believed that the greater part of the cost of the instrumental equipment might be defrayed by fixing the prices of the berths slightly in excess of the contract charge.

The Committee was duly elected, and 130 provisional applications for berths were received; but when it became necessary to ask for definite promises, only thirteen members ratified their applications. The Committee attributed this extraordinary falling off in numbers to the unsettling effect of the war in South Africa. The project of chartering a steamer had consequently to be abandoned, but the Committee recommended that observations of the eclipse should be undertaken, and that the Societies should provide the necessary instruments. Accordingly the Societies placed at the disposal of the Committee a sum of money sufficient to procure certain of the instruments employed in the observations descried in this Report, and to cover the cost of freightage.

By the middle of 1900, having finished his editorial work on the "Elements," he resolved to transfer his principal scientific attention from the quaternion analysis to astronomy; I found him in this frame of mind when I visited Dublin on my way to the second International Congress of Mathematicians. I had the pleasure of spending three days as his guest at the observatory. A charming wife, two little daughters and a sister-in-law graced his home. On his work-table were photographs of the totality which he had secured as a member of the Eclipse Expedition sent out to Spain by the Dublin Scientific Societies; proof-sheets of the last pages of the second volume of the "Elements"; and preparations were being made to spend the vacation in Switzerland. Alpine climbing was one of his recreations; so proficient was he therein as to become a member of the Alpine Club.

At the dining-table much of our talk was about the two quaternion giants, Hamilton and Tait. About Hamilton's habits and peculiarities Joly had a great stock of information. That same dining-room was Hamilton's study; he worked in it like a recluse during the later years of his life while writing the "Elements"; at his death the floor was found covered knee-deep with manuscripts arranged in beds with convenient walks between; when the mass was wheeled out many kitchen plates were found along with the remains of chops and steaks. The explanation was that Hamilton rarely left the room for his meals; something was brought in to him, which as likely as not was never noticed. On the other hand Joly was anxious to hear about Tait, whom he had never met; and this I was able to supply, having been a pupil of that great teacher. He was the more interested in the matter as the Royal Irish Academy had just elected Tait to honorary fellowship. Another place of interest was the observatory garden. It is enclosed by a stone wall, and divided by shaded walks, one of which Hamilton named Wordsworth's walk. The poet Wordsworth had made it a favourite haunt when on a visit to Hamilton; their common interest lay in philosophy and poetry. One day Professor Joly took me to see the Quaternion bridge. We retraced the course which Hamilton walked on the memorable 16th day of October, 1843, starting from the observatory house, descending the Dunsink hill, following the path by the side of the Royal Canal, and finally arriving at the second bridge over the canal. The path goes under the arch, and Hamilton had merely to take a step or two to the side to find the stone surface on which he first inscribed the formula $i^{2} = j^{2} = k^{2} = ijk = - 1$. Of course the inscription has long since mouldered away.

Later in the day we visited Trinity College, where I had the honour of dining with my friend at the high table. Dinner over, we sought the library, but found it closed. I had not the pleasure of seeing the hall in which Hamilton, when only thirty years of age was knighted by the lord lieutenant on the occasion of the first meeting of the British Association in Dublin. So we strolled through the ground, and while viewing the antiquities of the college of Queen Elizabeth we had a lively discussion over the principles of quaternions.

The object of this paper is to include projective geometry within the scope of quaternions. The calculus, as established by Hamilton, was solely adapted to the treatment of metrical relations, but when we regard a quaternion as representing a weighted point, projective properties can be investigated with great facility.

The work was written in a marvellously short space of time - about a twelvemonth. He however, wrote mathematics, worked out examples, and pursued his reasoning with the facility and ease with which a ready writer of fiction might develop the events of a novel. This, about his last great work, was received with commendation on every side; a reception all the more flattering as those who were admirers of Tait's treatment of the subject had to adapt themselves to a somewhat different mode of development before they could appreciate the new writer's work. Indeed, the Hamiltonian method of establishing the laws of Quaternions is here in part abandoned. In this work the author makes use of a wonderfully extensive knowledge of the mathematics of every branch of Physical Science.

Outside his work he had an extensive knowledge of literature, especially Italian, and climbing was a passion. A keen member of the British Alpine Club, he spent his holidays in the Alps, scaling the most difficult peaks. He was especially fond of rock climbing. Despite a delicate appearance he possessed endurance, courage, and a keen sense of humour, once leading a group successfully down from the Eiger in a snowstorm.

Dublin has earned an unenviable notoriety for typhoid fever, and many typhoid fever epidemics have been traced to the use of contaminated milk.

If the attack is as severe as Jessie's, I know quite well I cannot hold out. For myself I am content, though I should have given much to save the pain that others may feel. I confess also that I should like to be allowed to finish my life's work. Many unsolved problems might have some light thrown upon them if I had a little more time. I might have a useful influence in the affairs of College. I feel it would be a pity ...