218 NA TURAL HISTOR Y OF SELBORNE. 



the air is very elastic, and a dead stillness prevails, one or two 

 syllables more might have been obtained ; but the distance rendered 

 so late an experiment very inconvenient. 



Quick dactyls, we observed, succeeded best ; for when we came 

 to try its powers in slow, heavy, embarrassed spondees of the same 

 number of syllables, 



" Monstrum horrendum, informe, ingens . . ." 



we could perceive a return but of four or five. 



All echoes have some one place to which they are returned 

 stronger and more distinct than to any other ; and that is always 

 the place that lies at right angles with the object of repercussion? 

 and is not too near nor too far off. Buildings, or naked rocks, re- 

 echo much more articulately than hanging woods or vales ; because 

 in the latter the voice is as it were entangled and embarrassed in 

 the covert, and weakened in the rebound. 



The true object of this echo, as we found by various experiments, 

 is the stone-built, tiled hop-kiln in Gally-lane, which measures in 

 front forty feet, and from the ground to the eaves twelve feet. The 

 true centrum phonicum, or just distance, is one particular spot in 

 the king's field, in the path to Nore-hill, on the very brink of the 

 steep balk above the hollow cart- way. In this case there is no 

 choice of distance ; but the path, by mere contingency, happens to 

 be the lucky, the identical spot, because the ground rises or falls so 

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

 mouth would at once be above or below the object. 



We measured this poly syllabi cal 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 after- 

 wards, 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 



