374 



Transactions of section b. 



(2) Whereas, according to Mallard and Le Chatelier, the flame velocities for 

 mixtures near the upper and lower limits would gradually approximate to the 

 zero velocity ordinate, as the limiting composition was approached, according 

 to Wheeler the velocities for both the upper and lower limiting mixtures are 

 considerable (in each case about 36 cm. per sec), and there is an abrupt 

 change from these velocities to zero velocity as the particular limiting composi- 

 tion is passed. 



Dr. R. V. Wheeler on Speeds of Uniform Movement of Flame through Methane- Air 

 Mixtures in Tubes of DifTeient Diameters. 



5 6 7 8 9 10 II 12 13 14 15 



% METHANE 



Fig. 2. 



(3) Whereas Mallard and Le Chatelier found a maximum velocity of 63 

 cm. per sec. for a mixture containing about 12'2 per cent, of methane, and a 

 rapid falling off in velocity as this particular composition is deviated from, 

 Wheeler finds a maximum velocity of 110 to 112 cm. per second for a series 

 of mixtures containing from 945 to 10'55 per cent, of methane. Such differences 

 as are thus disclosed only emphasise the need of a complete experimental revi- 

 sion of the subject. 



Messrs. Burgess and Wheeler have recently determined the limits of inflam- 

 mability of methane when mixed, at atmospheric temperature and pressure, with 

 ' atmospheres ' of oxygen and nitrogen containing less oxygen than ordinary air. 

 From their results (se€ table, fig. 3) it would appear that as the oxygen content 



