SAFETY LAMP 



735 



light a gas-flame by the Newman double gauze-lamp, whereas this may be done by 

 suddenly driving the flame through the single gauze of the Davy. 



Upton and Roberts' lamp, fig, 1742. This consists of a wire-gauze cylinder 

 5 inches long and U inch in diameter, which is attached to the cylinder in the 

 usual manner. The lower half is protected by a thick glass-cylinder, and the 

 remaining portion by one of copper, screwed to the upper ring of the frame. The air 

 for combustion passes through a range of small openings in the upper part of the 

 cistern into a space protected by a double shield of closely-compressed wire-gauze. 

 A cone of sheet metal stands above this shield and conducts the air directly upon the 

 wick. 



Martin's lamp was, in many respects, similar to Upton and Eoberts's, but so 

 constructed that the flame was extinguished as soon as an explosive mixture was 

 within the glass-cylinder. 



Dumesnil sought to increase the quantity of light, at the same time as he 

 protected the flame against any rapid current. The glass shield surrounding the 



1742 



1743 



flame is of carefully-annealed glass, and is protected from mechanical injury by curved 

 metal bars ; a chimney of sheet metal being above the glass, and all the air being 

 compelled to pass through apertures rendered safe by the use of wire-gauze. 



Dr. Clanny, already named, introduced a new lamp, with an impervious metal- 

 shield, having glass and lenses in its sides, only open at the highest part of the gauze- 

 cylinder for about 1^ inch. Thus there is no admission of air to the lamp, or of the 

 products of combustion from the lamp, except over the top of the shield. This in 

 many respects resembles Mueseler's lamp, to be next described. 



Mueseler's lamp is shown in section,/^. 1743. The cistern, opening for the \viek, 

 &c., are precisely the same as we find them in the Davy. A glass-shield occupies 

 about two-fifths of the entire height, the lower edge resting in an annular recess on 

 the upper surface of the cistern. A conical tube of metal carries off the products of 



