Figure 38 is a drawing of the Davy lamp. It is just an external view – no internal details are shown and there is no indication of its size. The base of the lamp is a cylindrical container for liquid. There is a filler tube and cap protruding at an angle from one side. The diameter of this container is larger than its height and provides a stable base for the lamp. On top of this container there is a gauze envelope contained within a simple frame. This assembly has a smaller diameter than the base container but is about three times higher. The frame comprises a supporting ring at the bottom and a flat disc at the top connected with 4 vertical rods in between. The gauze envelope looks flimsy and appears to be supported and partly protected by these four rods. The carrying handle is a simple ring attached to the top surface of the flat disc at the top of the gauze assembly.

 3.1 Problems in collieries