Sir Benjamin Baker and Sir John Fowler — the engineers and designers of the Forth Bridge — devised the human cantilever to explain the principle at a lecture to the Royal Institution in London in 1887.
Baker proclaimed that the cantilever was the most effective means of constructing long-span bridges. He explained:
'When a load is put on the central girder by a person sitting on it, the men's arms and the anchorage ropes come into tension, and then men's bodies from the shoulders downwards and the sticks come into compression.'
The man seated in the centre was Kaichi Watanabe, a Japanese engineer and student of Fowler and Baker who visited the UK to learn Western engineering techniques.
This item featured in our display, 'The Forth Bridge: Building an icon', at the Library from 1 April to 21 June 2015.