^20 THE NATURAL HISTORY 



speaker either retires or advances, that his mouth would 

 at once be above or below the object. 



We measured this polysyllabical echo with great exact- 

 ness, and found the distance to fall very short of Dr. 

 Plot's rule for distinct 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 Doctor's, as five to eight : but 

 then it must be acknowledged that this candid philoso- 

 pher was convinced afterwards, that some latitude must 

 be admitted of in the distance of echoes according to 

 time and place. 



When experiments of this sort are making, 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 a ruffling wind quite defeats the whole. 

 In a still, clear, dewy evening the air is most elastic ; and 

 perhaps the later the hour the more so. 



Echo has always been so amusing to the imagination, 

 that the poets have personified her ; and in their hands 

 she has been the occasion of many a beautiful fiction. 

 Nor need the gravest man be ashamed to appear taken 

 with such a phenomenon, since it may become the 

 subject of philosophical or mathematical inquiries. 



One should have imagined that echoes, if not enter- 

 taining, must at least have been harmless and inoffensive ; 

 yet Virgil advances a strange notion, that they are in- 

 jurious to bees. After enumerating some probable and 

 reasonable annoyances, such as prudent owners would 

 wish far removed from their bee-gardens, he adds 



