Hyper-radial or hyperradiant Fresnel lenses are

Fresnel lens A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships." The design allows the c ...

es used in

lighthouses A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid, for maritime pilots at sea or on inland waterways. Lighthouses mark ...

. They are larger than "first-order" lenses, having a focal length (radius) of 1330 mm (52.36 inches). The idea was mentioned by

Thomas Stevenson Thomas Stevenson PRSE MInstCE FRSSA FSAScot (22 July 1818 – 8 May 1887) was a pioneering Scottish civil engineer, lighthouse designer and meteorologist, who designed over thirty lighthouses in and around Scotland, as well as the Stevenson sc ...

in 1869 and first proposed by

John Richardson Wigham :''This article concerns the Irish-based inventor and lighthouse engineer, not his cousin the shipbuilder John Wigham Richardson''. John Richardson Wigham (15 January 1829 – 16 November 1906) was a prominent lighthouse engineer of the 19th cen ...

in 1872, and again proposed by Thomas Stevenson in 1885 (infringing Wigham's patent). The hyper-radial lens was made in 1885 by the F. Barbier Company in Paris as a test lens for the lighthouse illumination trials then going on at the

South Foreland Lighthouse South Foreland Lighthouses are a pair of Victorian lighthouses on the South Foreland in St. Margaret's Bay, Dover, Kent, England, used to warn ships approaching the nearby Goodwin Sands. There has been a pair of lighthouses at South Foreland ...

in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

(UK).

Chance Brothers Chance Brothers and Company was a glassworks originally based in Spon Lane, Smethwick, West Midlands (formerly in Staffordshire), in England. It was a leading glass manufacturer and a pioneer of British glassmaking technology. The Chance fami ...

Glass Company made their first hyper-radial lens in 1887 in the UK. These lenses were originally named biform, and later triform and quadriform lenses, by Wigham. Thomas Stevenson used the term hyperradiant lens, and later they were renamed the hyper-radial lens by James Kenward of the Chance Brothers Glass Company. The hyper-radial Fresnel lenses were the largest ever put into use and were installed in about two dozen major "landfall"

beacon A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More mode ...

s around the world. The recipients include Makapu'u Point lighthouse on

Oahu Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over t ...

Island in

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

Cabo de São Vicente Cape St. Vincent ( pt, Cabo de São Vicente, ) is a headland in the municipality of Vila do Bispo, in the Algarve, southern Portugal. It is the southwesternmost point of Portugal and of mainland Europe. History Cape St. Vincent was already sacr ...

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

, Manora Point in

Karachi Karachi (; ur, ; ; ) is the most populous city in Pakistan and 12th most populous city in the world, with a population of over 20 million. It is situated at the southern tip of the country along the Arabian Sea coast. It is the former cap ...

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

, the Bishop Rock off the coast of

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

(in the UK), Cabo de Santa Marta in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, and

Cape Race Cape Race is a point of land located at the southeastern tip of the Avalon Peninsula on the island of Newfoundland, in Newfoundland and Labrador, Canada. Its name is thought to come from the original Portuguese name for this cape, "Raso", mea ...

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

. By the 1920s, high-intensity lamp technology had rendered lenses of this size obsolete.

Lighthouses

Hyperradiant optics were installed in thirty-one lighthouses around the world. A large proportion were destined for lights around Great Britain and Ireland, with another four used at sites around Sri Lanka. Despite the improvements in lighting technology, a number are still in use today. Others are in museums, either on display or in storage. The remainder have been broken up or lost.

References

External links

{{Commons category, Hyperradiant fresnel lenses, Hyperradiant Fresnel lenses
Wikimap showing lighthouse locations

Lenses History of physics Lighthouse fixtures