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The Fresnel Lens

The first lighthouse in Yarmouth was erected in 1839. The lens that is now on display at the museum was installed in 1908. This new lens was a sophisticated improvement over the original. The "Fresnel" lens was named after its inventor, Augustin-Jean Fresnel (1788-1827), a French physicist and engineer. He devised a method of producing circularly polarized light and replaced mirrors with compound lenses in lighthouses.


The lens was built in Paris and cost $38,000 CDN. It weighs approximately 3,300 pounds and has 360 prisms. The lens floated in a vat of mercury and was rotated by weights, similar to a grandfather clock. Every night the lighthouse keeper and his assistant made three trips each up a series of narrow stairways to the top of the light to wind up the weights.

A new modern structure replaced the 122-year-old lighthouse in 1962 and a new light was installed to replace the Fresnel lens. Today, the Cape Forchu light station is a tourist attraction, accessible by road along a scenic route that offers views of both Yarmouth Harbour and the ocean.

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