The electric flash-lamp uses electric current to start

flash powder Flash powder is a pyrotechnic composition, a mixture of an oxidizer and a metallic fuel, which burns quickly (deflagrates) and produces a loud noise, regardless of confinement in some formulations. It is widely used in theatrical and display pyro ...

burning, to provide a brief sudden burst of bright light. It was principally used for

flash photography A flash is a device used in photography that produces a brief burst of light (lasting around of a second) at a color temperature of about 5500 Kelvin, K to help illuminate a scene. The main purpose of a flash is to illuminate a dark scene. Ot ...

in the early 20th century but had other uses as well. Previously, photographers' flash powder, introduced in 1887 by

Adolf Miethe Adolf Miethe (; 25 April 1862, Potsdam – 5 May 1927, Berlin) was a German scientist, lens designer, photochemistry, photochemist, photographer, author and educator. He co-invented the first practical photographic Flash (photography), flash and m ...

and Johannes Gaedicke, had to be ignited manually, exposing the user to greater risk.

Invention

The electric flash-lamp was invented by Joshua Cohen (a.k.a. Joshua Lionel Cohen of the Lionel toy train fame) in 1899, and by Paul Boyer in France. It was granted U.S. patent number 636,492.Patent No. 636,492
/ref> 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 Cohen'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 A box camera is a simple type of camera, the most common form being a cardboard or plastic box with a lens in one end and film at the other. They were sold in large numbers during the late 19th and early 20th centuries. The lenses are often single ...

: tripping the shutter ignites the

and releases the

potential energy In physics, potential energy is the energy of an object or system due to the body's position relative to other objects, or the configuration of its particles. The energy is equal to the work done against any restoring forces, such as gravity ...

of the exploding powder causing a bright flash for indoor photography.

Uses of flash-lamp

The main purpose of Cohen's invention was as a fuse to ignite explosive powder to get a photographer's flash. One of the first practical applications, however, for Cohen's flash-lamp was as underwater mine detonator fuses for the U.S. Navy.Aboutdotcom
''Cowen was an inventor of sorts; he developed a fuse to ignite photographic flash powder. Though the invention failed in its intent, the U.S. Navy bought up the fuses to use with underwater explosives.'' In 1899, the year the invention was patented, the government awarded Cohen a $12,000 contract for 24,000

naval mine A naval mine is a self-contained explosive weapon placed in water to damage or destroy surface ships or submarines. Similar to anti-personnel mine, anti-personnel and other land mines, and unlike purpose launched naval depth charges, they are ...

detonator fuses. The use of the flash for photography was dangerous, and photographers could get burned hands from the flash.

Electric apparatus applications

A 1910 brochure for the Nesbit High Speed Flashlight Apparatus says,

Footnotes

Bibliography

*Beyer, Rick, ''The Greatest Stories Never Told - 100 Tales from History to Astonish, Bewilder & Stupefy,'' The History Channel, 2000, {{ISBN, 0-06-001401-6 * Photographic lighting 1899 introductions Obsolete technologies

Invention

Uses of flash-lamp

Electric apparatus applications

See also

Footnotes

Bibliography