Broom Bridge

Broom Bridge, also known as Brougham Bridge, is a small bridge along Broombridge road which crosses the Royal Canal in Cabra, Dublin, Ireland. Broom bridge is named after William Broom, one of the directors of the Royal Canal company. Broom bridge is somewhat famous for being the location where Sir William Rowan Hamilton first wrote down the fundamental formula for quaternions on October 16, 1843, which is to this day commemorated by a on the northwest corner of the underside of the bridge.

The text on the plaque reads:

: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.

Given the historical importance of the bridge with respect to mathematics, mathematicians the world over have been known to make a pilgrimage of sorts to the site.

External links, references, and resources

* John C. Baez, [http://math.ucr.edu/home/baez/octonions/node24.html Directions, photos and discussion] , at University of California at Riverside
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* Irelands Royal Canal, Ruth Delany, ISBN 0 946640 92 0