308 The Natural History of Selborne 



immediately, if the speaker either retires or advances, that his 

 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. Plot's rule 

 for distinct articulation ; for the Doctor, in his " History of 

 Oxfordshire," allows a hundred and twenty feet for the return 

 of each syllable distinctly; hence this echo, which gives ten 

 distinct syllables, ought to measure four hundred yards, or 

 one hundred and twenty feet to each syllable; whereas our 

 distance is only two hundred and fifty-eight yards, or near 

 seventy-five 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 

 phenomenon, since it may become the subject of philosophi- 

 cal or mathematical inquiries. 



One should have imagined that echoes, if not entertaining, 

 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." 



