512 



AGRICULTURAL ENGINEERING 



amount of oxygen and necessitates more rapid ventilation. 



A large lamp will consume more oxygen than several persons. 



There is more or less smoke com- 

 ing from the flame, which settles 

 as soot upon the furniture and 

 walls of the room. 



The light from a kerosene lamp 

 is a yellowish orange. It is not 

 white enough to be a perfect light. 

 Authorities differ in regard to the 

 effect of the light from a kerosene 

 lamp upon the eye, but it is gen- 

 erally regarded as a quite suit- 

 able light. The addition of a 

 mantle, which is a net of rare 

 earths, to a kerosene lamp to in- 

 close the flame, increases the 

 efficiency many fold. This will 

 be shown definitely in the data 

 from tests which will follow. 

 Mantles, however, are very fra- 

 gile and increase the cost of keep- 

 ing the lamp in service. The 

 average kerosene lamp furnishes 

 light at the rate of 15 to 30 candle 

 power. 



It is to be noted from the 

 table that the mantle has a de- 

 cided effect upon the efficiency 

 of lamps, raising the candle- 

 power-hours per gallon from 600 

 to over 3000. Gasoline lamps are 

 in reality gas lamps, for they 



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