120 SOUND. 



place of the confessional; and a person, by placing himself 

 in the opposite point, distinctly heard every thing which was 

 said in the confessional. Secrets never intended for the pub- 

 lic ear thus became known, to the dismay of the confessors, 

 and the amusement of the people, until at last, a listener 

 discovered the secret, and the confessional was removed."* 



ESTHER. 



How disagreeable an echo is, in a room where people are 

 singing. 



MRS. F. 



In a small room an echo strengthens the voice, because it 

 is so soon reflected back from the walls that the echo is not 

 distinguished from the original sound; but, in large buildings 

 such as cathedrals, where the original sound and the echo are 

 distinctly separated, the effect is very disagreeable. I do not 

 call your attention to harmonic sounds, for the subject is too 

 long and too difficult for present discussion. 



FREDERICK. 



Is sound easily conveyed under water? 



MRS. F. 



Yes, with great velocity. It travels about 9000 feet in 

 three seconds, when the temperature of the water is at 62 

 Fahrenheit; and in the Lake of Geneva, some experiments 

 were made, which shows that it travels 4708 feet a second 

 when the temperature is at 46. 



FREDERICK. 



Aunt, the boys at school have often puzzled me, by tap- 

 ping with the head of a pin at one end of a log of timber, when 

 I heard the sound distinctly although I was placed at the 

 other. How is that accounted for? 



MRS. F. 

 By the property which solid bodies possess of transmitting 



* Travels through Sicily in 1824, by a Naval Officer. 



