OF SELBORNE 193 



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 philosopher 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 phaenomenon, since it may become the subject of 

 philosophical or mathematical inquiries. 



One should have imagined that echoes, if not entertain- 

 ing, must at least have been harmless and inoffensive ; yet 

 Virgil advances a strange notion, that they are injurious to 

 bees. After enumerating some probable and reasonable 

 annoyances, such as prudent owners would wish far removed 

 from their bee-gardens, he adds 



" aut ubi concava pulsu 



Saxa sonant, vocisque offensa resultat imago." 



This wild and fanciful assertion will hardly be admitted 

 by the philosophers of these days; especially as they all 



