# Charles Jasper Joly

### Quick Info

Born
27 June 1864
Tullamore, County Offaly, Ireland
Died
4 January 1906
Dunsink, Dublin, Ireland

Summary
Charles Joly was an Irish mathematician who did outstanding work on the quaternions. He became Andrews Professor of Astronomy in the University of Dublin and Royal Astronomer of Ireland at Dunsink Observatory.

### Biography

Charles Jasper Joly was the son of the Rev John Swift Joly (1818-1887) [7]:-
... a man of studious bent and author of archaeological studies of local interest ...
and Elizabeth Slator (1835-1904). John Swift Joly was rector of St Catherine's Church of Ireland, Tullamore and he came from a family who had emigrated from the Austrian Netherlands in the middle of the eighteenth century. His great-grandfather was Jean Jasper Joly (1740-1823) who came to Dublin from France in 1769. He was [3]:-
... financial secretary to the duke of Leinster ... later appointed keeper of the house of lords in Ireland, and owned several houses on Harcourt Street.
Jean Jasper Joly's son, Charles Joly, was the father of John Swift Joly who had married Elizabeth Slator, the daughter of Rev Nathaniel Robert Slator and Frances Alicia Berry, at St Mary's Church, Athlone, Ireland on 12 August 1863. Let us note at this point that there is some confusion in the literature between Charles Jasper Joly, the subject of this biography, and John Joly (1857-1933) who became a leading physicist. Charles Jasper Joly and the physicist John Joly were related since John Joly's grandfather Henry Edward Joly (1784-1852) was the brother of Jean Jasper Joly's son, Charles Joly. In fact John Joly is the author of [7] from which we have already quoted.

Returning to the Rev John Swift Joly and his wife Elizabeth, they had five children: Charles Jasper Joly (1864-1906), the subject of this biography; Henry Nathaniel Joly (1866-1954); Frances Isabel Joly (1868-1947); Isabel Emily Joly (1871-1921); and John Swift Joly (1876-1943). Henry Nathaniel Joly followed his father in joining the church while John Swift Joly Jr became a leading surgeon. Let us note here that Frances Isabel Joly married Henry Joly, the brother of the physicist John Joly.

When Charles Jasper Joly as still a baby, the family moved from Tullamore to Athlone were his father became the rector of the parish. He attended school in Portarlington for a short time, then spent four years attending the Grammar School in Galway. This Protestant school, established by the Erasmus Smith Trust in 1669, was, when Joly was a pupil, situated in College Street. The master was Robert Biggs, who had been appointed in 1875, and there were around 30 boarders and 40 day pupils. Joly gained a reputation as a fine mathematician, being awarded numerous prizes and medals, and won a scholarship to Trinity College Dublin which he entered in 1882. His performance as an undergraduate was good but not outstanding [7]:-
... 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.
Despite this slightly uninspiring undergraduate career, nevertheless Joly graduated in 1886 as the top mathematician of his year. At this stage, however, he decided not to pursue a career in mathematics but rather to specialise in experimental physics. Accordingly, after graduating he went to Berlin where he worked in Hermann von Helmholtz's laboratory with Arthur König (1856-1901). König was studying optics, in particular vision and its defects, and this was the path that Joly would probably have followed but for the death of his father on 3 December 1887. This required him to return to Ireland where he lacked the laboratory facilities to continue with his experimental studies, so he began to concentrate on mathematics with the aim of gaining a Trinity College Fellowship. John Joly writes [7]:-.
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 somewhat peculiar way that the Fellowship competition was organised meant that publishing original work was of no great help so it was not until he obtained the Fellowship that Joly began publishing mathematical papers relating to the quaternions. His first paper The theory of vector functions was read at the meeting of the Royal Irish Academy on 10 December 1894. He was elected a member of the Royal Irish Academy at the next meeting of the Academy on 14 January 1895. His next paper Scalar invariants of two linear vector functions was read at the meeting of the Royal Irish Academy on 9 December 1895 and, in 1896, four of his papers were published by the Royal Irish Academy, namely Quaternion invariants of linear vector functions and quaternion determinants; Vector Expressions for Curves; Properties of the General Congruency of Curves; and On the Homographic Divisions of Planes, Spheres, and Space, and on the Systems of Lines Joining Corresponding Points.

As a fellow, he tutored at Trinity College, and in 1896 he was appointed junior proctor. On 20 March 1897, Joly married Jessie Sophie Meade (1874-1945) in Dublin. Jessie, the youngest daughter of the solicitor Robert Warren Meade and Jessie Sophia Lyster Jameson, had been born in Dublin on 16 December 1874. Charles and Jessie Joly had three daughters: Jessie Elizabeth Joly (1898-1987); Lucy Mary Joly (1899-1966); and Frances Isabel Joly (1905-1982). Also in 1897 Joly was appointed as Andrews Professor of Astronomy in the University of Dublin and Royal Astronomer of Ireland at Dunsink Observatory. For someone passionately undertaking research on quaternions, what could have been a better appointment for Joly than to follow the inventor of quaternions into his residence at the old House at Dunsink Observatory [7]:-
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 1898 he was elected a fellow of the Royal Astronomical Society and in 1900 took part in the eclipse expedition to Spain organised by the Royal Dublin Society and the Royal Irish Academy. Joly described in his report [9] the difficulties encountered, probably as a result of the Boer War:-
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.
Their successful observations were made from just below the summit of the hill of Berrocalillo within walking distance of the town of Plasencia in western Spain.

Once established in Dunsink Observatory, Joly began publishing on both astronomy and on mathematics related to quaternions. For example in 1898 he published four mathematics papers, two of which are Astatics and quaternion functions and The associative algebra applicable to hyperspace. He had been working hard on editing a new edition of Hamilton's Elements of Quaternions and, in 1899, the first of the two volumes was published. For information see THIS LINK.

In 1900 most of his publications were on astronomy; for example Catalogue of the mean places of 321 stars deduced from observations made with the meridian circle at Dunsink (1898-1899), Table of instrumental errors, and others works in the publication Astronomical observations and researches made at Dunsink, the observatory of Trinity College.

In 1902 he published eight papers on mathematics, all related to work with quaternions, while he continued working on editing the second volume of his new edition of Hamilton's Elements of Quaternions. For more information about this volume, see THIS LINK.

Alexander Macfarlane was a Scottish mathematician who spent most of his career in the United States and in Canada. He had been taught by P G Tait and had a life-long interest in quaternions. In 1900 the International Congress of Mathematicians was held in Paris in August and Macfarlane travelled from Canada to Paris, stopping in Dublin for a few days to visit Joly. He writes [11]:-
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.
In 1903 Joly published the paper Quaternions and Projective Geometry which, being over 100 pages in length, could easily have been a book. The Abstract begins:-
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.
An extract from a review of this work is at THIS LINK.

Joly was elected a Fellow of the Royal Society in 1904, then in the following year, he published his book A Manual of Quaternions. The timing was not a coincidence, for 1905 was the centenary of Hamilton's birth [7]:-
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.
The Preface of this work can be read at THIS LINK.

There was a brief mention of Joly's love of climbing above but we give a further quote about this taken from Patricia Byrne's article [3]:-
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.
In 1905 he was at the height of his powers and he attended the seventy-fifth meeting of the British Association for the Advancement of Science held in South Africa in August-September of that year. The meetings for different sections of the Association were held in Cape Town and Johannesburg. Shortly after he returned to Dublin from South Africa, his daughter Jessie Elizabeth Joly contracted typhoid. The Irish Times of 6 November 1905 records:-
Dublin has earned an unenviable notoriety for typhoid fever, and many typhoid fever epidemics have been traced to the use of contaminated milk.
Soon Joly too became ill with the disease. He wrote to a friend (see [7]):-
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 ...
He died on 4 January 1906 and was buried at Mount Jerome Cemetery in Dublin.

### References (show)

1. K Bailey, A history of Trinity College Dublin 1892-1945 (University Press, Dublin, 1947).
2. R S Ball, Charles Jasper Joly, 1864-1906, Proceedings of the Royal Society 78 A (1906), 67-69.
3. P M Byrne, Joly, Charles Jasper, Dictionary of Irish Biography (Cambridge University Press, 2009).
4. Charles Jasper Joly, Monthly Notice of the Royal Astronomical Society 66 (1906), 177-178.
5. I Elliott and C Mollan, Charles Jasper Joly, in William E Wilson (1851-1908) - The Work and Family of a Westmeath Astronomer (Charles Mollan, 2018), 133-135.
6. R W H T Hudson, Review: Quaternions and Projective Geometry, by C J Joly, The Mathematical Gazette 2 (42) (1903), 370-371.
7. J Joly, Charles Jasper Joly, 1864-1906, Proceedings of the Royal Society 78 A (1906), 62-67.
8. C J Joly, Quaternions and Projective Geometry. [Abstract], Proceedings of the Royal Society of London 71 (1902-1903), 177-178.
9. C J Joly, The Total Solar Eclipse of 1900: Report of the Joint Committee Appointed by the Councils of the Royal Dublin Society and Royal Irish Academy, The Transactions of the Royal Irish Academy 32, Section A, Part IX (1902-1904), 271-298.
10. C G Knott, Review: Manual of Quaternions, by C J Joly, The Mathematical Gazette 3 (53) (1905), 229-231.
11. A Macfarlane, Charles Jasper Joly, Bulletin of the International Association for Promoting the Study of Quaternions and Allied Systems of Mathematics (1900), 46-51.
12. A A Rambaut, Obituary Notice. Charles Jasper Joly, Astronomische Nachrichten 170 (4078) (1906), 359.
13. G Scriven, In memoriam: C J Joly, Alpine Journal 23 (1906), 58.
14. P A Wayman, Dunsink observatory 1785-1985 (Royal Dublin Society, Dublin, 1987).
15. E T Whittaker, rev. Adrian Rice, Joly, Charles Jasper (1864-1906), mathematician and astronomer, Oxford Dictionary of National Biography (Oxford University Press, Oxford, 2004).

### Additional Resources (show)

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Honours awarded to Charles Joly

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Written by J J O'Connor and E F Robertson
Last Update June 2021