The Light Bulb

Most of us hardly notice an everyday, commonplace object such as a Light Bulb - until it burns out and needs changing, that is - and yet much of the modern life we take for granted would be impossible and even unbearable without this humble appliance. It seems a little weird to think that the concept of night life as we know it now was not as widespread before the invention of the light bulb. People did go out, of course, but the illumination from oil or gas was quite inferior and not conducive to many activities. In the 1800s, the most popular source of lighting was gas - it was also dirty and dangerous to use, emitting soot in large quantities in the first place and causing explosions and fire in the second. It really was exasperating and inconvenient to have it in a house filled with fine furniture and young children - unless you had a penchant for constant cleaning and supervising. Another drawback of gas was that it was not capable of powering other household appliances.

Inventions usually happen because there is a general demand for something that will improve and help the quality of human life. So it was in the case of the Light Bulb. Inventors, realizing the deficiencies of gas, began looking for a better light source and came up with one that was to be powered by electricity.

The basic idea was to put a filament in a vacuum and pass a current through the filament - the current would heat the filament and make it glow - and, voila, you would have light! This idea was put forward by the scientist James Prescott Joule - he theorized that if electric current was passed through a resistant conductor it would glow white-hot with heat energy turned to luminous energy. However, the main problem that remained here was finding a filament that wouldn't disintegrate too quickly - a long-lasting one in other words, so as to emit light for a longer period - and inserting it in an oxygen free vacuum. This, of course, took a long time and the work involvement of many inventors.

The credit of starting the trend towards electrical lighting goes to the English scientist, Sir Humphrey Davy. He invented an electrical battery while conducting experiments in electricity, and by connecting wires between the battery and a piece of carbon he found that the resulting current made the carbon glow and emit light. This invention, which was made in 1811, came to be called an Electrical Arc. Several years and several modifications later, it was decided to use the electrical arc in public lighting. The first experimental arc lights were installed in 1841 along the Place de la Concorde in Paris and other places in Europe and America soon followed suit. However the arc lightings were not long-lasting and furthermore were too bright to be used indoors in small spaces. Something more practical and reliable was needed.

In 1860, the English Physicist Sir Joseph Wilson Swan (1828-1914) became the first inventor to ever construct an electric bulb. He used a carbon paper filament that emitted enough light, but burned up too soon as Swan hadn't figured out how to maintain a vacuum. However, on 21 October 1879, he managed to produce a carbon filament light bulb that remained illuminated for 40 hours. A year prior to this, in 1878, he had successfully demonstrated his new electrical lamps in Newcastle, England, and still earlier he also had an article on his invention, on which he had taken a patent, published in the important science magazine, Scientific American.

The American inventor, Thomas Alva Edison, read this article and decided to improve on Swan's work. This was Edison's usual pattern of work - with the exception of the phonograph, which was his idea from scratch, he generally reworked already existing, less well-developed inventions. Also, far from being a solitary worker, Edison had a large staff to both conduct experiments for him and to travel wherever necessary to bring him the things he needed for his experiments. Edison also had his own glass-blowing shed to produce the required glass vacuum bulbs. A hard-working individual, who followed a painstaking trial and error method, Edison tested between 1878 and 1890 over tens of thousands of different carbonized plant filaments and fibers and other materials brought from all over the world especially in order to find their perfect filament for the electric bulb.

After experimenting unsuccessfully with carbon filaments, Edison switched to a platinum filament - he thought of using Tungsten, the filament that is used in modern light bulbs, but hadn't the equipment then to produce it. He began using the better and improved Sprengel Vacuum Pump in 1879 and this proved to be a major help. Since Platinum was too expensive, he reverted back to using carbon filaments. On 21 and 22 October, using a carbonized filament made of Clark's sewing thread he was able to produce a light bulb that stayed lit for 13.5 hours - later, by shaping the filament into the shape of a horse-shoe, the bulb was able to burn for over 100 hours. This was a very major break-through and eventually led to the commercial production of light bulbs.