Lewis lamp
Encyclopedia
The Lewis lamp is a type of light fixture
used in lighthouse
s. It was invented by Winslow Lewis
who patented the design in 1810. The primary marketing point of the Lewis lamp was that it used less than half the oil of the prior oil lamp
s which they replaced. The lamp used a similar design to an Argand lamp
, adding a parabolic reflector
behind the lamp and a magnifying lens made from 4 inches (101.6 mm) green bottle glass in front of the lamp. A similar variant using a parabolic reflector was created by the inventor of the Argand lamp, Aimé Argand
. While the Argand variant became widely used by European lighthouses, the Lewis lamp design was selected by the United States
for use in American lighthouses.
The Lewis lamp would use groups of lamps.
The Lewis lamp design proved to have several flaws. To begin, it was really an inferior version of the Argand lamp
. The reflector was made of copper with an interior silver plating to reflect light; however, the thin copper would warp under the heat of the lamps to become more spherical than parabolic. Also, the silver plating was of poor quality and would be scratched off during routine cleanings. Adding to the problem was poor draft for the combustion
gases, so that soot would build up on the components, decreasing any alleged improvement. In particular, there was a green lens, which ostensibly improved the visibility, but which was prone to being covered in soot. The sooting became such a problem that the lenses were removed from the lamps.
The Lewis lamp was the paramount design used in American lighthouses for a number of years. In part, this was due to the federal government's distinct preference for awarding contracts to the lowest bidder. It was also claimed that the Lewis lamp would use substantially less fuel than the Argand lamps, which was true (provided one did not take into account the quality of the illumination).
Additionally, there were allegations (never proved) of an untoward relationship between Mr. Lewis and the contracting federal officers. The better view seems to be that the federal officers were not engineers, and were in no way fit to make an evaluation of the quality of the lamps. In fact, Congress eventually established a committee process to review the specifications for the lamps. At a point, the federal officer made claims that the Fresnel lens
was too complicated to be used by members of the lighthouse service. In fact, such concerns turned out to be baseless.
In 1852 the Lewis lamps began being replaced with Fresnel lens
es, due to the improved viewing distance offered by the Fresnel lens design. This transition was completed by the end of the American Civil War
. Fresnel lenses were initially more expensive to install, but they used only one wick and provided better and more focused light, thereby using even less fuel than the Lewis Lamps.
Light fixture
A light fixture, light fitting, or luminaire is an electrical device used to create artificial light and/or illumination, by use of an electric lamp...
used in lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....
s. It was invented by Winslow Lewis
Winslow Lewis
Winslow Lewis was a sea captain, engineer, inventor and contractor active in the construction of many American lighthouses during the first half of the nineteenth century....
who patented the design in 1810. The primary marketing point of the Lewis lamp was that it used less than half the oil of the prior oil lamp
Oil lamp
An oil lamp is an object used to produce light continuously for a period of time using an oil-based fuel source. The use of oil lamps began thousands of years ago and is continued to this day....
s which they replaced. The lamp used a similar design to an Argand lamp
Argand lamp
The Argand lamp is home lighting oil lamp producing a light output of 6 to 10 candlepower which was invented and patented in 1780 by Aimé Argand...
, adding a parabolic reflector
Parabolic reflector
A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves. Its shape is that of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis...
behind the lamp and a magnifying lens made from 4 inches (101.6 mm) green bottle glass in front of the lamp. A similar variant using a parabolic reflector was created by the inventor of the Argand lamp, Aimé Argand
Aimé Argand
François Pierre Ami Argand was a Swiss physicist and chemist. He invented the Argand lamp, a great improvement on the traditional oil lamp. -Early years:...
. While the Argand variant became widely used by European lighthouses, the Lewis lamp design was selected by the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
for use in American lighthouses.
The Lewis lamp would use groups of lamps.
The Lewis lamp design proved to have several flaws. To begin, it was really an inferior version of the Argand lamp
Argand lamp
The Argand lamp is home lighting oil lamp producing a light output of 6 to 10 candlepower which was invented and patented in 1780 by Aimé Argand...
. The reflector was made of copper with an interior silver plating to reflect light; however, the thin copper would warp under the heat of the lamps to become more spherical than parabolic. Also, the silver plating was of poor quality and would be scratched off during routine cleanings. Adding to the problem was poor draft for the combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
gases, so that soot would build up on the components, decreasing any alleged improvement. In particular, there was a green lens, which ostensibly improved the visibility, but which was prone to being covered in soot. The sooting became such a problem that the lenses were removed from the lamps.
The Lewis lamp was the paramount design used in American lighthouses for a number of years. In part, this was due to the federal government's distinct preference for awarding contracts to the lowest bidder. It was also claimed that the Lewis lamp would use substantially less fuel than the Argand lamps, which was true (provided one did not take into account the quality of the illumination).
Additionally, there were allegations (never proved) of an untoward relationship between Mr. Lewis and the contracting federal officers. The better view seems to be that the federal officers were not engineers, and were in no way fit to make an evaluation of the quality of the lamps. In fact, Congress eventually established a committee process to review the specifications for the lamps. At a point, the federal officer made claims that the Fresnel lens
Fresnel lens
A Fresnel lens is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design...
was too complicated to be used by members of the lighthouse service. In fact, such concerns turned out to be baseless.
In 1852 the Lewis lamps began being replaced with Fresnel lens
Fresnel lens
A Fresnel lens is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design...
es, due to the improved viewing distance offered by the Fresnel lens design. This transition was completed by the end of the American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...
. Fresnel lenses were initially more expensive to install, but they used only one wick and provided better and more focused light, thereby using even less fuel than the Lewis Lamps.