The true object of this echo, as we found by various experiments, is the stone-built, tiled hop-kiln in Galleylane, which measures in front 40 feet, and from the ground to the eaves 12 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 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 phenomenon, 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 prudent owners would wish far removed from their bee-gardens, he adds... aut ubi concava pulsu Saxa sonant, vocisque offensa resultat image.
This wild and fanciful assertion will hardly be admitted by the philosophers of these days; especially as they all now seem agreed that insects are not furnished with any organs of hearing at all. But if it should be urged, that though they cannot hear yet perhaps they may feel the repercussion of sounds, I grant it is possible they may.
Yet that these impressions are distasteful or hurtful, I deny, because bees, in good summers, thrive well in my outlet, where the echoes are very strong: for this village is another Anathoth, a place of responses or echoes. Besides, it does not appear from experiment that bees are in any way capable of being affected by sounds: for I have often tried my own with a large speaking-trumpet held close to their hives, and with such an exertion of voice as would have hailed a ship at the distance of a mile, and still these insects pursued their various employments undisturbed, and without showing the least sensibility or resentment.
Some time since its discovery this echo is become totally silent, though the object, or hop-kiln remains: nor is there any mystery in this defect, for the field between is planted as an hop-garden, and the voice of the speaker is totally absorbed and lost among the poles and entangled foliage of the hops. And when the poles are removed in autumn the disappointment is the same; because a tall quick-set hedge, nurtured up for the purpose of shelter to the hop ground, entirely interrupts the impulse and repercussion of the voice: so that till those obstructions are removed no more of its garrulity can be expected.
Should any gentleman of fortune think an echo in his park or outlet a pleasing incident, he might build one at little or no expense. For whenever he had occasion for a new barn, stable, dog-kennel, or the like structure, it would be only needful to erect this building on the gentle declivity of an hill, with a like rising opposite to it, at a few hundred yards distance; and perhaps success might be the easier ensured could some canal, lake, or stream, intervene. From a seat at the centrum phonicum he and his friends might amuse themselves sometimes of an evening with the prattle of this loquacious nymph; of whose complacency and decent reserve more may be said than can with truth of every individual of her sex;since she is... quae nec reticere loquenti, Nec prior ipsa loqui didicit resonabilis echo.
I am, etc.
P.S. -- The classic reader will, I trust, pardon the following lovely quotation, so finely describing echoes, and so poetically accounting for their causes from popular superstition:
Quae bene quom videas, rationem reddere possis Tute tibi atque alus, quo pacto per loca sola Saxa pareis formas verborum ex ordine reddant, Palanteis comites quom monteis inter opacos Quaerimus, et magna dispersos voce ciemus.
Sex etiam, aut septem loca vidi reddere voces Unam quom jaceres: ita colles collibus ipsis Verba repulsantes iterabant dicta referre.
Haec loca capripedes Satyros, Nymphasque tenere Finitimi fingunt, et Faunos esse loquuntur;Quorum noctivago strepitu, ludoque jocanti Adfirmant volgo taciturna silentia rumpi, Chordarumque sonos fieri, dulceisque querelas, Tibia quas fundit digitis pulsata canentum:
Et genus agricolum late sentiscere, quom Pan Pinea semiferi capitis velamina quassans, Unco saepe labro calamos percurrit hianteis, Fistula silvestrem ne cesset fundere musam.
Lucretius, lib. iv. 1. 576.
Letter XXXIX
To The Honourable Daines BarringtonSelborne, May 13, 1778.
