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 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 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 
