Canal-side pilgrimage recalls inspired piece of vandalism


IRELAND'S MOST famous mathematician was something of a vandal, scratching the formula for one of his greatest discoveries on to a bridge in Cabra.

All was forgiven yesterday, however, as Cabra Community Council helped to celebrate the miscreant, one William Rowan Hamilton, who committed that offence one day in 1843.

The structure, Broombridge, now bears no sign of the graffiti, but each year Hamilton's discovery is marked with a pilgrimage from his former home at Dunsink Observatory and along the Royal Canal.

Hamilton later described how, in a flash of inspiration upon reaching Broombridge, he created Quaternions. The term means little to most, but his maths is in widespread use today to create special effects in films like Matrix Reloadedand in computer games for characters such as Lara Croft from Tomb Raider.

Yesterday saw the 21st Hamilton Walk, which takes place, rain or shine, on the 16th. NUI Maynooth's Prof Tony O'Farrell started it in 1989. "I thought that there should be something for mathematicians, and to celebrate this remarkable person." Maynooth colleague Dr Fiacre O'Cairbre has taken up the mantle of organising the walk, and yesterday he was blessed with sunny weather.

The 150 walkers' greatest chore during the saunter was avoiding the many cowpats dotted about the grounds owned by the Ashtown Food Research Centre.

It was smooth sailing once on the canal, however, with a wide paved towpath offering easier passage than Hamilton would have enjoyed in 1843.

Dublin City Council has reconditioned a plaque marking that fateful day in 1843 which was unveiled by Éamon de Valera in 1958. "To all mathematicians around the world this is a known bridge and a famous thing," said Prof O'Farrell.

The walk is now bracketed by Maths Week Ireland, aimed at making maths fun and interesting.

While Maynooth can lay claim to the walk, Waterford Institute of Technology's Eoin Gill and Sheila Donegan proposed and started the week in 2006. People initially were aghast, asking "Who would go to a maths week of their own free will?" he acknowledged. It has grown rapidly. "It is a movement, if you like," he said.

Answer to yesterday's puzzle: Figure b will not fold into a cube