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
Safety lamp of air. The Marsaut was one of the first lamps to be fitted with a shield, in the illustration (right) the bonnet can be seen surrounding the gauzes. A shielded Marsaut lamp can resist a current of 30 feet per second. The Bainbridge is a development of the Stephenson. A tapered glass cylinder surrounds the flame, and above that the body is a brass tube. The top of the tube is closed by a horizontal gauze attached to the body of the lamp by small bars to conduct heat away. Air enters through a series of small holes drilled in