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History of artificial light sources
The brightness of the Sun is so great that few artificial light sources can compete. But at night, we have to make do with the pitiful reflection of the Sun’s light from the Moon’s surface – and not all the time.
So, because mankind could not bear to live in darkness, they had to invent alternative products. Before electric lights, people used many different tools to light up, from the most “classic” like fire to the most modern and advanced like lasers.
Fire: The Gift of Prometheus
The first artificial light source was fire. According to Greek mythology, Prometheus gave fire to mankind. Fire served humans as a constant source of light, while torches became a form of “fire in hand” can be moved
The design of the fire has changed over time: from a simple fireball drawn from a fire pit to a stick wrapped in rags and soaked in petroleum, fat, or cooking oil. Torch is a very ancient invention and is believed to have been around for about a million years. Today torches are still used, although not very commonly.
The distant descendants of today’s torches used gas to light the Olympic flame, while flares were used by armies, hunters, and tourists for disguise or signaling at night.
In addition to torches in the Stone Age, mankind also invented oil lamp – a pot filled with fat or cooking oil, with a wick soaked in it (made of hemp or cloth), a fire will be lit at the tip of that wick.
In the third millennium BC appeared first candle – solid animal fat sticks that are melted with a wick inside when burned. In the Middle Ages, whale oil and beeswax were used as fuel for candles, while in modern times we use paraffin for this.
Torches, candles and oil lamps give off very weak light. The spectrum of open fire is very different from the solar spectrum that nature has trained the human eye to see. Most of the radiation falls in the thermal (infrared) range. Visible light is emitted mainly by carbon atoms heated by the flame to high temperatures.
The visible spectrum of fire covers only a part of the yellow and red ranges. Working in such light was almost impossible and many medieval workshops banned work requiring night vision under artificial light, because the quality of the product would be greatly reduced.
Gas lamps light up the streets
In the 19th century, gas lighting was widely used. In 1807, the first gas street light The first gas lamps were lit in Pall Mall, one of London’s central streets. By 1823, more than 340 km of London streets were lit by 40,000 gas lamps.
They were lit by hand each night by specialized workers called lamplighters. This profession was once highly selective and in some countries was a highly honorable one.
However, gas lighting is not very efficient. The problem is that if the flame burns little oxygen, it produces bright light but a lot of smoke, while a smokeless flame (when there is a lot of oxygen) is actually not visible.
In 1885, Wellsbach (Freiherr von Welsbach) proposed the use of a burning net – a cloth bag soaked in a solution of inorganic substances (various salts). When burned, the cloth bag would burn and the thin “frame” that remained would glow brightly. By the end of the 19th century, kerosene lamps had appeared, which we can still see today. Most of them were equipped with a burning net, which is now made of metal or asbestos.
The first steps of electric light
The first electric light source was oddly enough battery powered light In fact, the light emitted is not from an incandescent bulb, but from an electric arc between carbon electrodes, and the battery takes up an area about the size of a desk.
In 1809, Humphry Davy demonstrated the arc light at the Royal Institution in London. There were no electric generators at the time (Faraday had discovered the phenomenon of induction in 1832) and batteries were the only source of electrical energy.
In 1878, Pavel Yablochkov improved the design by placing the electrodes vertically and separating them with an insulating layer. This design was called the “Ned Yablochkov” and quickly became used around the world. The Paris Opera House was once illuminated by these “candle” there.
Electric arc Because it produced a fairly even and even bright light spectrum, it soon became popular and widely used. By 1884, major American cities were lit by more than 90,000 arc lamps.
Light bulb filament
Most people credit Edison with the invention of the incandescent light bulb. However, despite his great achievements in this field, he did not invent the electric light bulb.
The first incandescent lamps were more like jewelry or art, both in their complexity and cost. Long before Edison, in 1820, Warren De la Rue placed a platinum wire in a glass jar that had been evacuated of air and passed an electric current through it. It was successful, but it was a… platinum lamp. It was so expensive that widespread use was impossible.
Many inventors experimented with other materials. In 1879, independently, Joseph Sven and Thomas Edison developed the carbon fiber filament lamp. With his invention, Edison organized a huge demonstration: on New Year’s Eve 1880, he used 100 of his lamps to illuminate the streets, his personal laboratory, and the town station of Menlo Park.
Trains were packed with people wanting to see this miracle, the Pennsylvania Railroad even had to add extra trains to New Jersey. Edison’s lamp lasted about 100 hours, consumed 100W, and emitted 16 candelas of light (for comparison, a modern 100W incandescent lamp produces about 100-140 candelas).