HOMOGENEOUS YELLOW LIGHT. 



183 



or any accidental current of air, is capable of blowing out 

 this flame, so that it is necessary to have a contrivance 

 for sustaining it. The method which I used for this pur- 

 pose is shown in Fig. 22. A small gas tube ale, arising 

 from the main burner M N of the gas lamp P Q, termi- 

 nates above the burner, and has a short tube d e, moveablc 

 up and down within it, so as to be gas-tight. This tube 

 d e, closed at e, communicates with the hollow ring/ g, in 

 the inside of which four apertures are perforated in such 



Fig. 22. 





a manner as to throw their jets of gas to the apex of a 

 cone, of which / g is the base. When we cause the gas to 

 flow from the burner M, by opening the main cock A, it 

 will rush into the tube abed, and issue in small flames 

 at the four holes in the ring/0. The size of these flames 

 is regulated by the cock b. The inflammation, therefore, 

 of the ignited gas will be sustained by these four subsidiary 

 flames through which it passes, independent of any agita- 

 tion of the air, or of the force with which it issues from 

 the burner. On a projecting arm e Ji, carrying a ring h, 





