Prof. F. Clowes. 



[Feb. 2, 



502 



ages found were : carbon dioxide 18'5, carbon monoxide 5'4, hydrogen 



76-1. 



In this gas the oil flame showed no trustworthy indication until 



4 per cent, of water-gas was present, when the height of the cap was 

 10-9 mm. ; the cap rose to 15'3 mm. with 5 per cent, of water-gas. 

 The cap over the standard hydrogen flame was 15'3 mm. when 0*25 

 per cent, of the gas was present, and rose gradually to 32 mm. when 



5 per cent, was present. These results would indicate the flame-test 

 to be of inferior delicacy for water-gas, but they require to be 

 repeated with water-gas of better quality before final conclusions 

 are drawn. 



[January 27. The flame- test, as applied to water-gas, was further 

 investigated in the test-chamber, by employing an artificially prepared 

 mixture of the separate gases. This mixture approximately corre- 

 sponded to the average composition of water-gas. The percentages 

 found on analysis were as follows : 



Hydrogen 49'6 



Carbon monoxide 40'8 



Carbon dioxide 2*6 



Nitrogen 7 



The complete series of flame-cap measurements are tabulated 

 below and are graphically represented in fig, 9 : 



Percentages of carbon monoxide in the air less than O2 to 0*4, 

 which is stated by the Prussian Firedamp Commission to be a 

 poisonous proportion, are thus easily detectible by the hydrogen flame 

 test in the safety -lamp.] 



In these measurements a delicate thread of flame, surmounting the conical 

 cap, was not included. 



