Gas detector early detection methods relied on less precise detectors. Through the 19th and early 20th centuries, coal miners would bring canaries down to the tunnels with them as an early detection system against life-threatening gases such as carbon dioxide, carbon monoxide and methane. The canary, normally a very songful bird, would stop singing and eventually die if not removed from these gases, signaling the miners to exit the mine quickly. The first gas detector in the industrial age was the "flame safety lamp" (or Davy lamp) was invented by Sir Humphry Davy (of England) in 1815 to detect the presence of
Hefner lamp Hefner lamp The Hefner lamp, or in German Hefnerkerze, is a flame lamp used in photometry that burns amyl acetate. The lamp was invented by Friedrich von Hefner-Alteneck in 1884 and he proposed its use as a standard flame for photometric purposes with a luminous intensity unit of the Hefnerkerze (HK). The lamp was specified as having a 40 mm flame height and an 8 mm diameter wick. The Hefner lamp provided the German, Austrian, and Scandinavian standard for luminosity during the late nineteenth and early twentieth centuries. The unit of light intensity was defined as that produced by the