Category Archives: Ireland

Hamilton’s quaternions in Broombridge

Hamilton plaque at Broombridge. Source:

Sir William Rowan Hamilton was walking through this brisge in Dublin on the 16th October, 1843, when he has one of his wonderful ideas: his quaternions. Nowadays, this very important moment in the History of Mathematics is recorded on a plaque located in the North-West corner of the bottom of the bridge. We can read:

Here as he walked by
on the 16th of October 1843
Sir William Rowan Hamilton
in a flash of genius discovered
the fundamental formula for
quaternion multiplication
i² = j² = k² = ijk = −1
& cut it on a stone of this bridge.

William Rowan Hamilton (midnight, 3-4 August 1805 – 2 September 1865)

I’ve never been in Dublin yet but I am sure that I am going to visit it very soon… very soon.

Location: Broombridge in Dublin (map)