Flash-lamp
Encyclopedia
The electric flash-lamp is a device that uses an electrical circuit to trigger a fuse to ignite explosive powder (e.g., magnesium
) for a brief sudden burst of bright light ("flash") from a chemical reaction of flash powder
burning. It was principally used for flash photography in the early 20th century, but had other uses as well.
(a.k.a. Joshua Lionel Cowen of the Lionel toy train fame) in 1899. It was granted U.S. patent number 636,492. This "flash
" of bright light from the flash-lamp was used for indoor photography in the late nineteenth century and the early part of the twentieth century.
Joshua Lionel Cowen's flash-lamp patent 636,492 reads in part,
The principle of operation of the electrical flash-lamp is linked to the shutter of an early box camera
: tripping the shutter ignites the flash powder
and releases the potential energy
of the exploding powder causing a bright flash for indoor photography.
for the U.S. Navy. In 1899, the year the invention was patented, the government awarded Cowen a $12,000 contract for 24,000 naval mine
detonator fuses.
Since early flashlights used energy-inefficient carbon filament bulbs, the batteries ran down quickly, and consequently they could only be used for brief flashes of light, hence the popular American and Canadian term flashlight.
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
) for a brief sudden burst of bright light ("flash") from a chemical reaction of flash powder
Flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and if confined produces a loud report. It is widely used in theatrical pyrotechnics and fireworks and was once used for flashes in photography.Different varieties of flash powder are made from...
burning. It was principally used for flash photography in the early 20th century, but had other uses as well.
Invention
The flash-lamp was invented by Joshua CohenJoshua Lionel Cowen
Joshua Lionel Cowen , born Joshua Lionel Cohen, was an American inventor and the cofounder of Lionel Corporation, a manufacturer of model railroads and toy trains....
(a.k.a. Joshua Lionel Cowen of the Lionel toy train fame) in 1899. It was granted U.S. patent number 636,492. This "flash
Flash (photography)
A flash is a device used in photography producing a flash of artificial light at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene. Other uses are capturing quickly moving objects or changing the quality of light...
" of bright light from the flash-lamp was used for indoor photography in the late nineteenth century and the early part of the twentieth century.
Joshua Lionel Cowen's flash-lamp patent 636,492 reads in part,
The principle of operation of the electrical flash-lamp is linked to the shutter of an early box camera
Box camera
The box camera is, with the exception of the pin hole camera, a camera in its simplest form. The form of the classic box camera is no more than a cardboard or plastic box with a lens in one end and film at the other. A simple box camera has only a single element meniscus fixed focus lens and...
: tripping the shutter ignites the flash powder
Flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and if confined produces a loud report. It is widely used in theatrical pyrotechnics and fireworks and was once used for flashes in photography.Different varieties of flash powder are made from...
and releases the potential energy
Potential energy
In physics, potential energy is the energy stored in a body or in a system due to its position in a force field or due to its configuration. The SI unit of measure for energy and work is the Joule...
of the exploding powder causing a bright flash for indoor photography.
Uses of flash-lamp
The main purpose of Cowen's invention was as a fuse to ignite explosive powder to get a photographer's flash. One of the first practical applications, however, for Cowen's flash-lamp was as underwater mine detonator fusesFuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
for the U.S. Navy. In 1899, the year the invention was patented, the government awarded Cowen a $12,000 contract for 24,000 naval mine
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
detonator fuses.
Electric apparatus applications
A 1910 brochure for the Nesbit High Speed Flashlight Apparatus says,Flashlight
On 10 January 1899 American Electrical Novelty and Manufacturing Company obtained U.S. Patent No. 617,592 (filed 12 March 1898) from a David Misell, an employee of Cowen. This "electric device" designed by Misell was powered by "D" batteries laid front-to-back in a paper tube with the light bulb and a rough brass reflector at the end. Misell, an inventor, had previously invented a portable electric lamp in 1895 as patent number 551,394. He also invented a bicycle head lamp in 1896 as patent number 559,143.Since early flashlights used energy-inefficient carbon filament bulbs, the batteries ran down quickly, and consequently they could only be used for brief flashes of light, hence the popular American and Canadian term flashlight.