1893.] 



A New Portable Miner s Safety-lamp. 



499 



FiG. 9. Heights of Flame-caps in Coal-gas and in Water-gas. 



Coal-gas in continuous lines, ^vatergas in dotted lines. 



HH, cap heights over 10 mm. standard hydrogen flame. 



H^H!, cap heights over hydrogen flame, reduced to 5 mm. in the presence of the 



gas. 



H 2 H 2 , cap heights over 15 mm. hydrogen-flame. 

 OO, cap heights over oil flame, adjusted until the maximum cap is seen. 



VOL. LFI. 



2 L 



