The tantalum lamp

As a collector of stamps and stationery from Bosnia and Herzegovina, I came across an envelope bearing a pair of 5 Heller green stamps with an image of Emperor Franz Joseph I. The stamp was issued on October 4, 1912. The date in the Sarajevo stamp impression is February 22, 1914, just four months before the assassination of Franz Ferdinand of Austria in Sarajevo, one of the triggers for the start of the First World War. In itself, such an envelope is not remarkable. But what caught the eye was the advertising logo in the bottom left: Tantal Lampe. A light bulb went on somewhere. Was this the precursor to the tungsten light bulb? And the internet provided the answer once again. The tantalum light bulb was introduced by Siemens, an invention of the Swiss Otto Feuerlein. He took over the management of the Siemens light bulb factory in 1902, where light bulbs with carbon filament were still being manufactured at the time. In fact, a colleague of Feuerlein, Werner von Bolton, had discovered the element tantalum as a potential successor to the carbon filament. By 1905, production had progressed to the point where the tantalum lamp could be put into mass production. Tantalum is a chemical element with the symbol Ta and atomic number 73. With that, the carbon filament was obsolete. The tantalum lamp now became the standard worldwide, an advancement due to lower power consumption and higher light output. The lamps were also less fragile and could withstand bumps more easily during transport. However, the tantalum lamp had only a short lifespan. In 1910, an even better filament was invented, made of tungsten. A small vignette on an envelope that nevertheless shed some light on the history of the light bulb for me. And that from Bosnia and Herzegovina!