Davys for testing. In particular "overmen ... whose lamps are mostly used to detect the presence gas, should avoid such [Clanny] lamps". Mueseler lamp The lamp is a modified Clanny designed by the Belgian Mathieu-Louis Mueseler. The flame is surrounded by a glass tube surmounted by a gauze capped cylinder. Air enters from the side above the glass and flows down to the flame before rising to exit at the top of the lamp. So far this is just a Clanny, but in the Mueseler a metal chimney supported on an internal gauze shelf conducts the combustion products to the top of the lamp. Some Mueseler lamps were fitted with a mechanism which locked the base of the lamp. Turning down the wick eventually released the base, but by then the flame was extinguished and therefore safe. The lamp was patented in 1840 and in 1864 the Belgian government made this type of lamp compulsory. In the presence of firedamp the explosive mixture is drawn through two gauzes (cylinder and shelf), burnt and then within the chimney are only burnt gases, not explosive mixture. Like a Clanny, and the Davy before it, it acts as an indicator of firedamp, burning more brightly in its presence. Later models had graduated shields by which the deputy could determine the concentration of firedamp from the heightening of the flame. Whilst the Clanny will continue to burn if laid on its side, potentially cracking the glass; the Mueseler will extinguish itself due to the stoppage of convection currents. The lamp is safe in currents up to 15 feet per second. Marsaut lamp The Marsaut lamp is a Clanny with multiple gauzes. Two or three gauzes are fitted inside each other which improves the safety in a draught. Multiple gauzes will however interfere with the flow 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. Bainbridge lamp 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