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THE POPULAR SCIENCE MONTHLY. 



each blow of the hammer, emitted a sort of musical roar, shortening 

 and lengthening as the successive sound-pulses reached it. The gases 

 were then admitted. Twenty -five flat jets of coal-gas ascended from 

 the tubes below, and twenty-five cascades of carbonic acid fell from 



the tubes above. That which was a homogeneous medium, had now 

 fifty limiting surfaces, from each of which a portion of the sound was 

 thrown back. In a few moments these successive reflections became 

 so effective that no sound having sufficient power to affect the flame 



