134 TROUBLES IN CHAPTER V iCn. V 



With the acetylene flame if too much gas is turned on the flame 

 will smoke and roar. 



222. The image of the lamp flame may show on the screen. 

 This is because the objective is too far from the condenser or the 

 lamp flame is not in the proper position with reference to the con- 

 denser. Try removing the lamp farther from the condenser or 

 bringing it nearer. When it is in the correct position its image 

 will not appear on the screen. 



223. Roaring of the alco-radiant lamp. If the roaring is 

 excessive it shows that the pressure on the alcohol reservoir is too 

 great. This can be remedied by ceasing to pump the air in 

 till the noise is within reasonable bounds. 



