In early lighthouses, the light source was a kerosene lamp or, earlier, an animal or vegetable oil Argand lamp, and the lenses rotated by a weight driven clockwork assembly wound by lighthouse keepers, sometimes as often as every two hours.

A Fresnel lens can capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances.

Other illustrations include a lion-shaped mountain representing the Sierra Leone mountain range, the Alexandria lighthouse ( laid horizontal ), the mythical Mountains of the Moon ( legendary source of the Nile River ) in central Africa, and either the Table Mountain or Drakensberg range in South Africa.

Beaming ( short for relativistic beaming ) affects the apparent brightness of something just as a lighthouse affects the appearance of its light source: the light source appears dim or unseen to a ship except when the lighthouse is directed towards a ship where it appears very bright.

After convincing the police that his story is true, Kyle, Michael and Caitlin decide to lead the Tooth Fairy to the largest source of light in the town-the lighthouse.

In the United States, whistles were also used where a source of steam power was available, though Trinity House, the British lighthouse authority, did not employ them, preferring an explosive signal.

The trade, which in its heyday could yield 500, 000 eggs a month, was the source of conflict between the egg collecting companies and the lighthouse keepers.

Had a UFO been present, the airmen should have reported a second source of light ( the lighthouse ) in the same line of sight.

# " To the Lighthouse "-Build a lighthouse by creating a light source visible from great distances while at sea, as well as create the lighthouse infrastructure and make the light flash.

Three new generators were placed in the lighthouse to provide an electric light source, the lantern being re-lit on 6 August 1959.

The Rhine springs from a source nearby ( Tomasee ), which is marked by a working lighthouse.

A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and used as an aid to navigation for maritime pilots at sea or on inland waterways.

There are some methods seldom used today such as " dipping a light " to calculate the geographic range from observer to lighthouse

A smaller lighthouse at Dover, England also still exists as a ruin about half the height of the original. The light would have been provided by a fire at the top of the structure.

According to Smithsonian magazine, the first Fresnel lens was used in 1823 in the Cordouan lighthouse at the mouth of the Gironde estuary ; its light could be seen from more than out.

In 1968, a third lighthouse was built on the Calf after a severe fire destroyed the Chicken Rocks light.

The lighthouse is unusual in that the light itself is switched on and off in sequence ( four flashes every 20 seconds ), rather than using lenses to create a rotating beam.

Trinity House's activities as a lighthouse authority are financed from “ light dues ” levied on commercial shipping calling at ports in the United Kingdom.

The lighthouse lantern is above the ground, but the lighthouse sits on a hill, putting the light above sea level.

The lighthouse keepers ' dwellings and other historic light station buildings are now home to the lighthouse museum, with exhibits on lighthouse life, lighthouse and Fresnel lens restoration, the keepers and their families, Daytona Beach and Florida history, and shipwrecks.

In 1813 Congress allocated $ 15, 000 to build a new lighthouse on Bald Head as the existing light had been rendered inoperable by erosion.

The light was in disrepair and of little use with most vessels entering New Inlet, which had its own lighthouse at Federal Point.

Image: Conneaut light. jpg | Conneaut lighthouse

This lighthouse was of utmost importance because it controlled the nighttime pass ; whoever governed the light beacon regulated the night time passageway.

It was used for the construction of lighthouses on Maplin Sands in the Thames Estuary ( the first light application, in 1838 ), at Morecambe Bay ( the first completed, in 1839 ), and at Belfast Lough where his lighthouse was finished in July 1844.

The prominent white streak on the cliff facing the mainland ( see photo ) is often thought by visitors to be bird droppings: although many parts of the islands do exhibit this colouring, in this case it is the result of chalk deposits from the many years of spent calcium carbide from the lighthouse being thrown down the cliff ; this calcium carbide was used to generate acetylene which was used as fuel for the light before electricity came.

One popular cruise is from Caletilla Beach to Roqueta Island, which has places to snorkel, have lunch, a small zoo and a lighthouse.

Interestingly, this ACT exclave surrounds a small exclave of NSW territory, namely the Point Perpendicular lighthouse which is at the southern tip of the Beecroft Peninsula.

It is shaped somewhat like a short lighthouse ( with no illumination ).

The lighthouse remains a civic symbol of the city of Alexandria and of the Alexandria Governorate with which the city is more or less coterminous.

* There is a historic stone lighthouse located on Cumberland Head, which is privately owned.

* On Point Au Roche, part of Beekmantown, New York, there is a privately owned, historic lighthouse.

* 1859 – The current Cape Lookout, North Carolina, lighthouse is lit for the first time.

Germany's smallest lighthouse is located here, being also the only one with a thatched roof.

Used horizontally, a sextant can measure the apparent angle between two landmarks such as a lighthouse and a church spire, which can then be used to find the distance off or out to sea ( provided the distance between the two landmarks is known ).

This phenomenon is known as elastic scattering, and the electron ( or lighthouse ) is known as the scatterer.

* November 1 – The current Cape Lookout, North Carolina, lighthouse is lighted for the first time ( its first-order Fresnel lens can be seen for 19 miles ).

* 785 – 805: Chinese geographer Jia Dan describes large lighthouse pillars built in the Persian Gulf, which is confirmed a century later by al-Mas ' udi and al-Muqaddasi.

* Claudius begins construction of Portus, the harbour bears a lighthouse and is sited on the right bank of the Tiber.

Once a flourishing small community with a lighthouse, the island was destroyed by coastal erosion and now exists as a shoal that is exposed at low tide.

The northernmost point of the Weser is marked by the Alte Weser lighthouse.

* The Sea Captain on The Simpsons uses the title as an exclamation when his ship is about to hit a lighthouse in the 1997 episode El Viaje Misterioso de Nuestro Jomer.

On the west side of the island is Keahole Point lighthouse ; NGS data predicts the lighthouse's lat-lon by the stars will come out to 19. 7244 N 156. 0787 W. Based on the astro lat-lons the distance from the Hilo water tank to the Keahole Point lighthouse calculates to be 108. 8 km, but the actual distance turns out to be 105. 5 km.

The uses of these islands vary: Davids ' Island, the former location of the U. S. Army ’ s Fort Slocum, is currently unoccupied but is slated for use as passive parkland ; Glen Island is a County park for passive and active recreation ; Huckleberry Island is largely undeveloped and has one of the largest rookeries for some shore bird species in western Long Island Sound ; Columbia Island was the former site of CBS television broadcast antennas and is currently unoccupied ; Echo Island is used by a private yacht club ; Execution Rocks is the site of a 19th century lighthouse listed on the National Register of Historic Places ; Pea Island is owned by Huguenot Yacht Club but remains undeveloped ; Goose Island is undeveloped ; Clifford, Harrison and Tank Islands are part of a nature preserve and city park ; and Oak and Pine Islands are used as private residences.