**Charles Graves** was an Irish mathematician who published on geometry and on Gaelic history. He and his brother John are credited with inspiring Hamiton to invent the quaternions.

- We note that Robert Perceval Graves was the author of the 3-volume work Life of Sir William Rowan Hamilton (Hodges, Figgis, Dublin, 1882-1889).
- At the time when Graves began his studies William Rowan Hamilton was Andrews' Professor of Astronomy in Trinity College Dublin while Franc Sadleir (1775-1851) was Erasmus Smith professor of mathematics.
- Having the aim of a military career, Graves had become an expert swordsman, an expert horseman and an enthusiastic sportsman.
- Graves graduated in 1835 with a B.A. having specialised in mathematics and mathematical physics.
- It was highly unusual for anyone to succeed in winning a fellowship at their first attempt but Graves achieved this distinction.
- The first of Graves' published works appeared in 1841.
- Bertrand's famous treatise on integral calculus (1864) attributed Graves's theorem to Chasles, who arrived at it later by an independent investigation.
- In a long appendix to the volume Graves gave a method of treating curves on a sphere corresponding to the Cartesian method on the plane, arcs of great circles taking the place of right lines.
- In the same year Graves made two contributions to the Proceedings of the Royal Irish Academy, namely On Certain General Properties of Cones of the Second Degree and On the Application of Analysis to Spherical Geometry.
- The fellowship that Graves held at Trinity College, Dublin, meant that he was given a very heavy teaching load and time for research was hard to come by.
- However, he had been elected to the Royal Irish Academy in 1837 and, in 1843, following James MacCullagh moving from the Chair of Mathematics to the Erasmus Smith Chair of Natural and Experimental Philosophy, Graves was appointed as professor of mathematics at Trinity.
- He had a long association with George Boole and Graves was one who wrote a letter of support for Boole when he was a candidate for the professorship of mathematics at Queen's College, Cork, in 1849.
- It is likely that MacCullagh's interest in these topics was a major factor in Graves becoming interested in Irish culture and, in particular, in deciphering Ogham script.
- Graves gave his method of deciphering the script in On a General Method of Deciphering Secret Alphabetic Writings, as Applicable to the Irish Ogham (1848) and further work on this topic appeared in On the Ogham Character (1848), On the Ogham Character and Alphabet.
- Let us look at Graves' method of deciphering the Ogham script which he gives in the 'General Method of Deciphering' paper by quoting from this paper.
- The discovery is due to the Rev Charles Graves, Professor of Mathematics in the University of Dublin.
- Professor Graves informs me that he has verified the principle by constructing sequence tables for all the European languages.
- Graves' interest in Irish culture led to him being appointed in 1852 to a Commission set up to translate, edit and publish the ancient laws of Ireland.
- This Commission became known as the Brehon Laws Commission and Graves made his rooms in Trinity College available to two men who worked on the project.
- In the 1850s Graves leased Parknasilla, a house about 5 km from the village of Sneem in County Kerry.
- In 1860 Graves was appointed as Dean of the Chapel Royal.
- The Chapel Royal is in Dublin Castle and, in that role, Graves attended all the ceremonial occasions held in the Castle.
- We note here that some of Graves papers written after he became bishop, have been listed as authored by Charles Graves and C Limerick.
- This is a simple error arising from the fact that, as Bishop of Limerick, Graves would sign himself Charles Limerick or C Limerick.
- We mentioned above that Graves had been elected to the Royal Irish Academy in 1837.
- Graves continued to serve as President of the Academy until 1866 so he was still President when Sir William Rowan Hamilton died in September 1865.
- Although Graves had many duties as Bishop of Limerick, nevertheless he was able to continue his interest in both mathematics and in the Ogham inscriptions.
- Two further mathematics papers by Graves on this topic appeared, namely The Focal Circles of Spherical Conics (1889) and On the Plane Circular Sections of the Surfaces of the Second Order (1890).
- In addition to honours mentioned above, Graves was elected a fellow of the Royal Society of London in 1880 and was awarded an honorary degree by Oxford University in 1881.
- Graves was a close friend of the Catholic bishop who had encouraged his own flock to attend the funeral.
- Graves was buried in Limerick Cathedral.

Born 6 December 1812, Dublin, Ireland. Died 17 July 1899, Dublin, Ireland.

View full biography at MacTutor

Origin Ireland

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive