324 SOUND. 



the object which reflects it, the longer will the echo be in 

 returning. 



Consequently, a person speaking in a large hall, is 

 obliged to speak more slowly than he would in a small 

 room, in order to give the echo time to return from all 

 parts of the building. If he neglects this, and speaks as 

 rapidly as usual, it will be almost impossible to under- 

 stand him, as the words which he utters will be con- 

 founded with the returning echo. 



Remarkable Echoes. 



The following are some of the most celebrated echoes, 

 which writers have noticed. 



Dr Plot, in his Natural History of Oxfordshire, men- 

 tions an echo in Woodstock Park, in Oxfordshire, which 

 repeats seventeen syllables in the day-time, and twenty 

 in the night. The difference if there is any is probably 

 occasioned by the stillness of the night which renders 

 the sounds more audible. 



Harris describes an echo on the north side of the 

 Shipley church, in Sussex, as repeating twentyone sylla- 

 bles distinctly, under favorable circumstances. 



Dr Birch informs us, that there was an echo at Rose- 

 neath, in Argyleshire, in Scotland, which distinctly 

 repeated, three times, a tune played on a trumpet. When 

 a person, placed at a proper distance, plays eight or ten 

 notes, they are correctly repeated, but a third lower ; 

 after a short silence, another repetition is heard, in a 

 still lower tone ; and, after another short interval, there is 

 a third repetition, in a yet lower tone. 



Addison describes an echo at the palace of Simonetta. 

 near Milan, as returning the sound of a pistol fiftysix 

 times. The palace has two wings ; and, when a pistol 

 is fired from a window in one of the wings, the sound is 

 reflected from a dead wall in the other wing, and is heard 

 from a window in the back front. The following ac- 

 count of it, however, from Keysler, is more minute and 

 interesting. 



' At the Marquis Simonetta's villa is a very extraordi- 

 nary echo ; it is occasioned by the reflection of the 

 voice between the opposite parallel wings of the building, 

 which are fiftyeight common paces from each other, and 



