Geordie lamp the base so that it gave more light and tried new versions on 4 and 30 November. This was presented to the Literary and Philosophical Society (Lit & Phil) of Newcastle upon Tyne on 5 December 1815. Although controversy arose between Stephenson's design and the Davy lamp (invented by Humphry Davy in the same year), Stephenson's original design worked on significantly different principles from Davy's final design. If the lamp were sealed except for a restricted air ingress (and a suitably sized chimney) then the presence of dangerous amounts of firedamp in the incoming air would (by its combustion) reduce
Safety lamp 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. 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