ARLA/CLUSTER: Fresnel também inventou lentes para os farois

[João Costa > CT1FBF]

Fresnel invented the lighthouse lens

The lighthouse with its beam of light relies on a lens that is now
routinely used by voice light-beam experimenters - and is finding more
modern applications.

Augustin Fresnel designed a lens of large aperture and short focal
length, in a much smaller package than was the convention.

Lighthouses were able to blaze many times brighter, further and more
efficiently.

As the French Lighthouse Commission Secretary of the day he
illuminated the entire coastline of France.

The British initially shunned it, and so did the Americans - but quickly
acknowledged the superiority of the Fresnel lens.

A fascinating book entitled 'A Short Bright Flash' by Theresa Levitt, talks
about the man, has 60 illustrations and is a must-read for history,
lighthouse and Fresnel fans.

Jim Linton VK3PC