The Royal Canal

The Royal Canal is the second of the canals that reach the Shannon River from Dublin, and was opened in 1817 some thirteen years after the Grand Canal. Work began in 1790 and the total cost of construction was £1,421,954.

It is 90 miles long and there are 46 locks to navigate. On its way from Dublin it passes through Maynooth, Enfield, Mullingar and Ballymahon. At the Dublin end it passes by Croke Park, where the terrace close to it is called the ‘Canal End’ before it reaches Spencer Dock then the Liffey, and the Dublin Bay beyond.

Brendan Behan memorial at Whitworth Road

The canal was constructed for the dual purpose of freight movement and passenger transport to-and-from the centre of the country. It was very popular and profitable for many years before being slowly undermined by the introduction of the railway, and later by road haulage. And by the 1970s it had fallen into disuse and plans were considered to fill in sections of it and construct a road. These, thankfully, were challenged, and work by the Royal Canal Amenity Group and Waterways Ireland saw the canal fully reopened in 2010.

Broome Bridge, near Castleknock, has a special place in Irish and scientific history. For it was here, on the 16^th October 1843, that mathematician William Rowan Hamilton, who lived in Dunsink Observatory, in a moment of inspiration, realised the solution for quaternions, a problem he had been working on for some time. Excited by what he had discovered, he scratched the solution on the bridge with his penknife. This moment is celebrated annually at the bridge on the 16^th October, now known as Broome’s Day.

The canal has featured in a famous song from the play The Quare Fellow by Brendan Behan. It is set in Mountjoy Gaol where Behan had spent some time, and refers to the metal triangle that was beaten to waken inmates.

And the auld triangle went jingle-jangle

All along the banks of the Royal Canal

(Photo: Dennis Fisk)

William Rowan Hamilton – Genius

WRH in the Royal Irish Academy

The word genius is defined as ‘a person who displays exceptional intellectual ability, creativity or originality associated with the achievement of new advances in a domain of knowledge’ and it most definitely applies to William Rowan Hamilton.

Hamilton was born on the 4^th August 1805, the fourth of nine children, to Archibald Hamilton, a solicitor, and his wife Sarah and lived at 38 Dominick Street, Dublin. When he was three years old he was sent to live with his uncle James Hamilton, a teacher and linguist, who ran a school in Trim, County Meath, and showed an exceptional talent for languages from an early age. By the age of thirteen he had acquired the same number of languages, including ancient Latin and Greek, most modern European languages and Persian, Arabic and Sanskrit. Late in life he often relaxed by reading books in Persian or Arabic!

South Telescope

When he was eight he lost a mental arithmetic contest against the American prodigy Zerah Colburn who was touring Europe and astounding audiences with his ability. After his loss Hamilton devoted his time to mathematics and less to the study of languages. The year before he entered university he spotted an error in Laplace’s Mechanique Celeste, and this brought him to the attention of John Brinkley, the Royal Astronomer of Ireland. He said of Hamilton: ‘This young man, I do not say will be, but is, the first mathematician of his age.’  

He entered Trinity College when he was eighteen and studied mathematics and Classics gaining an unprecedented ‘optime’ in both. Soon afterwards, in 1827, he was appointed, while still an undergraduate, Professor of Astronomy at Trinity College. Although this was a great opportunity for Hamilton, which included a decent salary and the title of Royal Astronomer of Ireland, it was also a place for his sisters to live. However, he spent most of his time studying mathematics and very little effort was devoted to astronomy. He was, however, twice awarded the Cunningham Medal, the highest honour bestowed by the Royal Irish Academy. And in 1835 he was knighted for his services to science; and both he and Michael Faraday were awarded the Queen’s Medal by the Royal Society that same year.

Plaque on Broom Bridge

While on his way along the Royal Canal to a meeting in the Royal Irish Academy on 16^th October 1843 the discovery of quaternions took shape in his mind. He etched the equation on Broome Bridge and the famous event is celebrated each year with a walk from the observatory to the site. Today quaternions are used in computer graphics, signal processing and orbital mechanics. As such, their use can be found in todays’ spacecraft attitude-control systems, and their discovery played a significant role in putting Man on the Moon. That’s out of this world, and something the Dunsink Astronomer would have loved.

Dunsink Observatory