OF SELBORNE. 31 



mouth would at once be above or below 

 the object. 



We measured this polysyllabical echo 

 with great exactness, and found the distance 

 to fall very short of Dr. Plofs rule for dis- 

 tinct articulation: for the Doctor in his 

 history of Oxfordshire, allows 120 feet for 

 the return of each syllable distinctly : hence 

 this echo, which gives ten distinct syllables, 

 ought to measure 400 yards, or 120 feet, to 

 each syllable ; whereas our distance is only 

 258 yards, or near 75 feet, to each syllable* 

 Thus our measure falls short of the Doc- 

 tor's, as five to eight : but then it must be 

 acknowledged that this candid philosopher 

 was convinced afterwards, that some lati- 

 tude must be admitted of in the distance 

 of echoes according to time and place. 



When experiments of this sort are mak- 

 ing it should always be remembered that 

 weather and the time of day have a vast 

 influence on an echo ; for a dull, heavy, 

 moist air deadens and clogs the sound; and 

 hot sunshine renders the air thin and weak, 

 and deprives it of all its springiness ; and 



