The problem was not so much the lamp itself, but the power source. In spite of the poor alternatives, it took more than 70 years before the arc lamp resulted in practical lighting devices on a large scale. Every street lamp had to be lit individually every night, and extinguished every morning. ![]() Streets were lit by oil or open flame gas lamps (or not at all). Oil lamps had similar drawbacks, and the recent open flame gas lamps were only a modest improvement - the only advantages being that they were a little bit stronger and cleaner and only had to be ignited once. ![]() It took an awful lot of work to install, to light and to replace all those candles (see below), not to mention the toxic smoke, the smell, the heat, the built-up of soot and the risk of fire resulting from this. Large buildings, like theatres, were sometimes lit by hundreds or even thousands of candles. As a way of lighting up streets and large interior spaces, however, the technology sounded very promising. It was obvious that the powerful light of an arc lamp was absolutely unsuitable for use in a room. The discovery of the arc light was a spectacular feat, because the light it produced was incomparably stronger than anything else available at that time: candles, oil lamps and – appearing around the same time – open flame gas lights, which produced only 10 to 20 candlepower. The temperature in the arc could rise to 4,000 degrees Celsius (more than 7,000 degrees Fahrenheit), the highest temperature that man achieved until the arrival of the atomic bomb. By further moving the rods just a little bit apart, the current flows through the vaporizing carbon and spans the air gap with an “arc” of intense light.Īn electric candle typically produced a light of 1,500 to 6,000 candlepower, which corresponds to the output of 11 to 43 modern 100-watt incandescent light bulbs. If two electrified carbon rods touch each other, some of the carbon vaporizes. In an incandescent light bulb (which was developed only 70 years later) an electric current is transferred over a filament, but in the case of an arc lamp this happens through the air instead. Davy, who can be considered the true founder of electric lighting, discovered that a blinding white light was produced by hooking up two charcoal rods to a battery, and bringing them very close together. The arc light (or “electric candle”) was invented and demonstrated by Sir Humphry Davy at the very beginning of the 19th century in England.
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