SAFETY LAMP

or Davy Lamp | (from its inventor, Sir Humphry Davy), | is used in coal mines as illuminant and Site SAFETY cence MATCH Nei ne Re indicator of explosive gases. It consists of an oil lamp, the flame being completely enveloped with wire gauze, which rapidly conducts the heat away on large surface exposed that the cannot pa through at a sufficiently high temperature to ignite explosive gases. These it can be made to detect by turning down the flame to a point, when a light flame cap appears if from 11% to 3 per cent. of methane firedamp is present. A similar type lamp was invented by George Stephen son, the famous engineer, in 1815, same year as Davy’s invention. Davy lamp has undergone various modifications, increasing its light-giving power and its resistance to draughts. A largely-used or oa variety j is the Marsaut double-gauze safety lamp. The modern electric hand lamp is more luminous, but does not serve as an indicator explosive gases.