Z A. ASHE ON A NEW INCANDESCENT LIGHT 



Bunsen burners, but none that I could make or purchase would 

 produce a flame sufficiently small in size and high in tempera- 

 ture to attain the object in view ; probably, also, the pressure of 

 the gas supply was too low for the purpose. This failure, however, 

 led to the making of trials with other forms of burner, and in 

 the end I found that the burners employed in acetylene lamps,, 

 at that time coming into use, were, in their smaller sizes such 

 as the 00000 made by Messrs. Bray, and passing about 1 cubic 

 foot of gas per hour, far superior to any Bunsens which I could 

 construct of similar power, and that such small burners gave 

 when used with coal gas a perfectly blue and well-oxydised 

 flame of high temperature well suited to the purpose. 



A fragment of a mantle say about l/4th inch square held in 

 such a flame is raised to a high degree of incandescence and would 

 be considered a brilliant little light, but the delicate nature 

 of the mantle renders such a fragment quite unsuitable for repeated 

 use and a more substantial substitute must be prepared. 



This can be done by cutting an upright mantle into narrow 

 strips about l/4th inch broad, and 2 inches or more long, then 

 rolling each strip round a knitting needle or smooth wire, securing- 

 the outer ends from uncoiling by means of a drop of gum or 

 perhaps better still by wetting it with the tongue. The little 

 rolls so made are slid off the wire and set aside to dry, though 

 they can be used immediately if needed. 



The lamp-stand may be of a simple description, consisting 

 of a firm base from which rises a vertical rod to which is clamped 

 a piece of 3/8 gas tubing, having the previously described burner 

 at its outer end. Above this gas tube is separately clamped a 

 horizontal rod tipped with a short length of platinum or nickel 

 wire, its outer end being bent to an angle of 45 degrees upwards* 

 Over this projecting wire is slipped one of the rolls by means of 

 the little hole left in its centre when winding it round the 

 knitting needle and a light then applied to the gas jet. (See 

 illustration.) 



