244 LETTERS ON NATURAL MAGIC. 



LETTER VIII. 



Musical and harmonic sounds explained Power of tweaking glasses 

 with the voice Musical sounds from the vibration of a column of 

 air And of solid bodies Kaleidophone Singular acoustic 

 figures produced on sand laid on vibrating plates of glass, and 

 on stretched membranes Vibration of fiat rulers, and cylinders 

 of glass Production of silence from two sounds Production of 

 darkness from two lights Explanation of these singular effects 

 Acoustic automaton Droz's bleating sheep Maillardefs singing 

 bird Vaucanson's flute-player His pipe and labor player 

 Baron Kempelen's talking engine Kratzenstein s speaking 

 machine Mr. Willis's researches. 



AMONG the discoveries of modern science there are few 

 more remarkable than those which relate to the produc- 

 tion of harmonic sounds. We are all familiar with the 

 effects of musical instruments, from the deep-toned voice 

 of the organ to the wiry shrill of the Jew's harp. We sit 

 entranced under their magical influence, whether the ear 

 is charmed with the melody of their sounds, or the heart 

 agitated by the sympathies which they rouse. But 

 though we may admire their external form, and the skill 

 of the artist who constructed them, we never think of 

 inquiring into the cause of such extraordinary combina- 

 tions. 



Sounds of all kinds are conveyed to the organ of hearing 

 through the air ; and if this element were to be destroyed 

 all nature would be buried in the deepest silence. Noises 

 of every variety, whether they are musical or discordant, 

 high or low, move through the air of our atmosphere at 

 the surface of the earth with a velocity of 1090 feet in a 



