1. From Ancient Times To Electrification
As an island nation, we in the UK are used to seeing lighthouses around our coasts, but have you ever stopped to think about once they have been first constructed and the way they labored in these early days.
The aim of lighthouses is clearly to mark dangerous coastlines, rocks and reefs and to aid navigation, especially at night or in misty conditions.
The primary recognized warnings made to boats of hazardous rocks and shores, have been fires, set at the sting of the water, nevertheless it was in Egypt that we first heard of actual structures being built, which used light to guide ships.
The Lighthouse of Alexandria
Built on the island of Pharos, the lighthouse was commissioned by Ptolemy in 290 B.C. It took 20 years to construct, and turned the tallest constructing in existence, aside from the nice Pyramid, standing at between 450 and 600 feet in height, and was recognised as one of the Seven Wonders of the World.
It is thought to have cost around the equivalent of three million dollars or £2.Eight million. Its design was nothing just like the slim constructions we’re conversant in right now. It consisted of three levels, the first being in the shape of a large box built on a 20 foot excessive stone platform. On top of this was an eight sided tower, followed by a cylinder that prolonged to an open cupola where the fire burned to provide the light. On its roof was a large statue, thought to be of the sea god Poseidon. The fire’s light was believed to have been projected into a beam by the use of a large curved mirror, probably product of polished bronze. It was said that ships might detect its signals up to a hundred miles away, the light from the tower by evening, and the smoke from the fire by day. This claim however seems a little bit extreme.
The lighthouse became so famous that the title “pharos” turned the foundation of the word “lighthouse” in many languages. It stood for over 1,500 years, surviving a tsunami in 365 Ad, but earth tremors resulted in cracks forming in the structure which needed restoration. Then, a major earthquake in the area, in the 14th century, triggered such extreme injury that the structure finally collapsed.
Other early lighthouses
In medieval times the Iranians apparently erected giant minaret towers in the mouth of the Persian Gulf to aid navigation. In China, the medieval mosque at Canton also had a minaret serving as a lighthouse, and in 1165 a pagoda known as the Liuhe Pagoda, was built in Hangzhou and acted as a lighthouse for sailors in the Qiantang River.
One of the oldest working lighthouses in Europe is Hook Lighthouse, constructed at Hook Head in County Wexford, Ireland in thirteenth century and inbuilt circular design. Two lighthouses, referred to as the Pharos, were built at Dover (UK) soon after the Roman conquest of Britain. They were constructed on two heights (the Jap and the Western). The one on the Eastern Peak still stands in the grounds of Dover Castle.
Another famous early Roman lighthouse is the Tower of Hercules, most likely built in the first century, on a peninsula at A Coruna in north-west Spain. It was initially recognized as the “Farum Brigantium”, the Latin word farum being derived from the Greek pharos.
The light was originally produced using a wood fired system located on the summit platform, however the lighthouse was abandoned after the Viking Invasions of 854-fifty six. It was restored within the 14th century when the city became one of the kingdom’s largest ports, and by the 17th century it had been fitted with a dome shaped lantern. More restoration was completed in the early stone island jacket junior ebay 18th century, and in 1847, a system using Fresnel lenses (see later) was put in. It was electrified in 1926, with a beam visible for as much as 32 nautical miles and is the oldest Roman lighthouse in use today.
Some early stone island jacket junior ebay lighthouses used wick lamps as a light source and often the beam could only journey just a few miles. The Argand hollow wick lamp and parabolic reflector were developed in Europe round 1781, while in the USA, whale oil was used with wicks until the Argand system was introduced around 1810,which was then later replaced with Colza oil (similar to rapeseed oil), lard oil and then Kerosene.
The Fresnel lens
In 1822 a Frenchman, named Augustin Fresnel, found out how to extend the light depth utilizing prisms, and the primary Fresnel lens was installed in 1822 within the Cordouan lighthouse in the mouth of the Gironde estuary. This light could possibly be seen from 20 miles or 32 km away. By the 1860s, low-light-loss Fresnel lenses, much larger than the unique ones, have been in use in lighthouses round Britain and France, their use quickly extending to Italy and further afield to Australia and America.
To create the flashing effect, designers had to come up with a way of making the lens revolve. This was accomplished utilizing a rotating stand with a clockwork mechanism with descending weights on cables. The keeper periodically cranked up the load to the highest of the lighthouse and as it descended, the lens revolved. The flashing effect was achieved each time a segment of the rotating lens passed between the lamp and the observer. The rate of rotation determined the frequency of the flash and made it potential for every lighthouse to have its personal recognisable sample.
The arrival of electricity
Across the turn of the 20th century, acetylene gas (electricity and carbide) began replacing kerosene, and around 1910 many lighthouses began using the clever device referred to as the Dalen Sun Valve, invented by the Swede, Stone Island Shop Gustav Dalen. The valve opened and closed the gas supply to the lamp in response to how a lot sunlight it received, so the lights might be turned on mechanically at dusk and off at dawn. Dalen also found out how you can store the gasoline in tanks and to interrupt its stream, inflicting the light to flash. Dalen’s innovations resulted in savings in gas and maintenance, as the lamps only needed servicing twice a year.
As electricity grew to become accessible, the clockwork mechanisms in the lighthouses were replaced by electric motors, with 100W bulbs offering the sunshine source, and electronically operated fog signals had been added. With all this electrification and automation, lighthouse keepers had been sadly obsolete and from the 1980 they grew to become superfluous to requirements. The last lighthouse within the UK to be automated was North Foreland in Kent, in 1998.
Right this moment
Many Fresnel lenses have been replaced by rotating aerodrome beacons which require less maintenance. The system of rotating lenses has in some circumstances been replaced by a high intensity light that emits short flashes, similar to the obstruction lights used to warn aircraft of tall buildings.
Recent improvements embrace Vega Lights, (lighthouse beacons providing a spread of up to 22 nautical miles with a a hundred Watt lamp). They can operate in remote, solar-powered places, on unattended sites, and require maintenance solely once a yr. There are within the area of 600 of these in operation around the world.
Technology moves on, and as new innovations such as GPS make navigation easier and safer, it may be tempting to suppose that lighthouses have had their day.
Personally I’d prefer to have a reliable backup to my GPS, and there is nothing so comforting on your first ever night watch below sail, than to see the beam of a lighthouse shining by the darkness, to rely the flashes and know that you’re where you should be.
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