Following my recent post about the Souter Point lighthouse in South Shields, Jack Kirby at Thinktank (the Birmingham science museum) mentioned the lighthouse optic they’ve got in their collection, from Longstone Lighthouse, off the Northumberland coast.
It’s by Chance Brothers, a Birmingham firm that specialised in precision optical technology such as lighthouse lenses, as well as being responsible for glazing the Crystal Palace, the Houses of Parliament and the dials of Big Ben.
As Jack pointed out, we’ve got a superb Chance Brothers lighthouse optic on show too – ours is from the Eilean Glas light on Scalpay in Scotland’s Outer Hebrides. You can see it in Making the Modern World, and it’s on loan to us from the wonderful National Museums Scotland.
These optical systems use the clever Fresnel lens system, in which the light is focused and directed by concentric rings of prisms. This makes them much lighter than one-piece lenses (though the glass in the Eilean Glas optic alone weighs three tons) and more powerful beams were made possible, saving lives at sea.
Bella Bathhurst’s book ‘The Lighthouse Stevensons’ tells the story of a remarkable family of engineers that designed lighthouses around the Scottish coast (including Eilean Glas), and is well worth a look.