496 



Prof. F. Clowes. 



[Feb. 2, 



FIG. 6. 



FIG. 0.-Actual Dimensions of Hydrogen Flames and Caps with Methane. 



The shaded flames are of the standard 10 mm. size ; their caps are shown at (H). 

 The dotted flames and caps (B^) correspond to the flame 15 mm. high in the gas. 

 The three figures to the right (H 2 ) represent 5 mm. flames and their caps ; flames 

 set in the gas. 



it gives strikingly regular indications up to 6 per cent., and 

 even higher percentages may be read off in a lamp with a long 

 glass. 



3. The standard 10-mm. hydrogen flame gives distinct indications 



from 0*25 to 3 per cent. ; the cap then becomes too high, for 

 measurement in the lamp ; but by reducing the flame to 5 mm., 

 cap-readings may be taken up to 6 per cent, of gas. 



The lower indications may similarly be increased by raising 

 the flame to 15 mm. 



4. The oil flame, produced by unmixed colza oil, gives no indica- 



tions with percentages below 2. With 1 per cent, of gas the 

 flame from colza mixed with an equal volume of petroleum 



