edged 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 even- 

 ing 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 phenome- 

 non, since it may become the subject of philosophical 

 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 pru- 

 dent owners would wish far removed from their bee- 

 gardens, he adds 



" — — — — — — aut ubi concava pulsu 



Saxa sonant, vocisque ofifensa resultat imago." * 



* " Nor place them where too deep a water flows, 



Or where the yew, their poisonous neighbour, grows ; 

 93 



