On January 15, 1803, Heinrich Daniel Ruhmkorff was born in Hanover, Germany. Rather than do any advanced schooling, he became an apprentice mechanic at the Bramah Company in London. The company founder, Joseph Bramah, was the inventor of the hydraulic press which was used in making the locks sold by them. In 1855, Ruhmkorff set up his own shop in Paris, gaining a reputation for selling high quality electrical apparatus. In 1851, Ruhmkorff patented the Induction coil and is sometimes credited with inventing it but Nicholas Callan actually invented it some 15 years earlier and Ruhmkorff just improved the design. Sometimes referred to as a Ruhmkorff coil, his induction coil could produce a spark 30 centimeters (about a foot) long. In contrast, Callans first coils could produce a spark 2-5 centimeters (an inch or two) but he eventually got that up to around 38 centimeters (15 inches) by using some of Ruhmkorffs ideas for improving it. in 1858, Napoleon III awarded him 50,000 franc prize for the most important discovery in electricity for that year. Another invention Ruhmkorff is famous for is a portable electric lamp, mentioned in several of Jules Vernes novels. Like the induction coil, he didnt invent the lamp but improved on it. The original inventors Alphonse Dumas (not related to Alexander) and Dr Camille Benoit had invented it independently and both were awarded a 1,000 franc prize by the French Academy of Science. The original invention was a Geissler tube (an early type of discharge tube) filled with carbon dioxide and excited by a battery powered induction coil, giving off a white light. The problem was that the carbon dioxide would break down over time so Ruhmkoff replaced it with nitrogen, which gives a red light, and replacing the plain glass with glass doped with uranium salts, which fluoresce with a green light. Although, the nitrogen has since been replaced by argon with a tiny amount of mercury and the glass is coated with a fluorescent substance instead of containing uranium, the principle for constructing a fluorescent light remains the same today. Ruhmkorffs induction coils were popular among electrical experimenters, notably Wilhelm Roentgen making x-rays with one but also used by scientists as varied as Heinrich Hertz, Gugliemo Marconi and Alexander Popov. For the most part Ruhmkorff was the first to commercialize electrical apparatus, improving on things already invented. Another such invention was a thermopile (a major improvement on the thermoelectric batteries invented by Thomas Seebeck and improved on by Georg Ohm), the voltage of which could be varied by connecting more or fewer junctions to the terminals (1844). Ruhmkorff died in Paris on December 20, 1877.
Posted on: Fri, 16 Jan 2015 03:11:10 +0000