INFLUENCE OF ELEVATION ON SOUNDS. 215 



As the traveller rises above the limit of life and 

 motion, and enters the region of habitual solitude, 

 the death-like silence which prevails around him 

 is rendered still more striking by the diminished 

 density of the air which he breathes. The voice 

 of his fellow traveller ceases to be heard even at 

 a moderate distance, and sounds which would 

 stun the ear at a lower level make but a feeble 

 impression. The report of a pistol on the top of 

 Mont Blanc is no louder than that of an Indian 

 cracker. But while the thinness of the air thus 

 subdues the loudest sounds, the voice itself 

 undergoes a singular change : the muscular 

 energy by which we speak experiences a great 

 diminution, and our powers of utterance, as well 

 as our power of hearing, are thus singularly 

 modified. Were the magician, therefore, who is 

 desirous to impress upon his victim or upon his 

 pupil the conviction of his supernatural power, 

 to carry him, under the injunction of silence, 



to breathe 



The difficult air of the iced mountain's top, 

 Where the birds dare not build, nor insect's wing 

 Flit o'er the herbless granite, 



he would experience little difficulty in asserting 

 his power over the elements, and still less in sub- 

 sequently communicating the same influence to 

 his companion." 



But though the air at the tops of our highest 

 mountains is scarcely capable of transmitting 

 sounds of ordinary intensity, yet sounds of extra- 

 ordinary power force their way through its most 

 attenuated strata. At elevations where the air 

 is three thousand times more rare than that 

 which we breathe, the explosion of meteors is 



