Machine-History.Com

Brush Arc Electric LampsIn 1775, Italian scientist Alessandro Volta devised the electrophorus, a device that produced a static electric charge and in 1800 he developed the voltaic pile, a forerunner of the electric battery. Building on these electrical discoveries, Sir Humphry Davy found that bright sparks were given off when the voltaic pile was discharged and a specially bright spark could be obtained by using well-burnt charcoal as electrodes. In 1802 Davy demonstrated the carbon arch or arc light with a battery of 150 cells. In 1808 with a battery of 2000 cells he was able to show a permanent flame of great length and dazzling brilliance.

At that time the only strong enough source of electricity was the galvanic battery. The commercial success of the arc lamp did not become possible until the dynamo became a reliable source of current. In the 1850's the arc light first came into public use at the Place de la Concorde in Paris.
In 1876 Charles Francis Brush produced an improved dynamo-electric machine. The Brush Electric Company by 1881 had sold or installed arc lamps the following:
* 800 lights in rolling mills, steel works, shops, etc.
* 1,240 lights in woolen, cotton, linen, silk, and other factories
* 425 lights in large stores, hotels, churches, etc.
* 250 lights in parks, docks, and summer resorts
* 275 lights in railroad depots and shops
* 130 lights in mines, smelting works, etc.
* 380 lights in factories and establishments of various kinds
* 1,500 lights in lighting stations, for city lighting, etc.
* 1,200 lights in England and other foreign countries.
* A total of over 6,000 lights

This video demo is of an arc torch used to heat metal, but it is a close relative, so I videoed & added to this article. Works like the arc lamps of the early 1800's to 1900.

The arc between the carbon rods is caused by a spark passing between them when they are brought into contact and separated. Minute particles of carbon are disintegrated by the spark. Either continuous (direct) or alternating current may be used. The carbon rod tips are consumed in this event and the rate is lessened if a globe is placed around the arc to prevent oxygen reacting with the carbon. Even if not sealed tight, the globe helps because the heated gases produced, prevents the entrance of new oxygen.
Arc lighting, being so intense was used less indoors but for many years outdoors and for searchlights etc. In the 1920's warships used arc lamps that gave illumination of up to 40,000 candle-power and a working range of 2 miles. ARC Tower Austin Texas 1895
In 1894-5 iron towers 150-165 feet high with arc lights were installed in Austin Texas. The light emanating from one of the towers with six arc lights was claimed to be sufficiently bright to see the time of night by an ordinary watch, within a radius of 3,000 feet.
Variations of the arc lamp produced have sealed chambers vacuumed of air and containing different gases including neon, argon, xenon, krypton, sodium, metal halide, and mercury. These gases are ionized (have more or less electrons than protons) and become electrically conductive. On some the arc is struck by an initial higher voltage igniter and a ballast then continue the arc with a lower voltage and current. On one device the Cooper Hewitt Mercury Vapor Lamp liquid mercury is flowed across electrodes then tilted to open the direct circuit and the mercury gas conducts an arc and light.