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 imago. 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 shewing the least sensibility or resentment. *The organs of hearing in insects are the antennæ, or horn-like processes, which stand out from the forehead. If these organs do not convey sound, in the same manner as the ears of other animals, they are, at least, very sensible of any concussion produced in the atmosphere by sounds, and if not the ears themselves, are, at least, analogous to them. The reflected sound of an echo cannot take place at less than fifty-five feet; because it is necessary that the distance should be such, and the reverberated or reflected sound so long in arriving, that the ear may distinguish clearly between that and the original sound. -ED 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 a 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 a 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 Quæ nec reticere loquenti, Nec prior ipsa loqui, didicit resonabilis echo. P.S. The classic reader will, I trust, pardon the following lovely quotation, so finely describing echoes, and so poetically acccounting for their causes from popular superstition : Quæ benè quom videas, rationem reddere possis LETTER LXXXI. TO THE HON. DAINES BARRINGTON. SELBORNE, May 13, 1778. DEAR SIR,- Among the many singularities attending those amusing birds, the swifts, I am now confirmed in the opinion that we have every year the same number of pairs invariably; at least the result of my inquiry has been exactly the same for a long time past. The swallows and martens are so numerous, and so widely distributed over the village, that it is hardly possible to recount them; while the swifts, though they do not all build in the church, yet so frequently haunt it, and play and rendezvous round it, that they are easily enumerated. The number that I constantly find are eight pairs, about half of which reside in the church, and the rest build in some of the lowest and meanest thatched cottages.* Now, as these eight pairs-allowance being made for accidents-breed yearly eight pairs more, what becomes annually of this increase? and what determines, every spring, which pairs shall visit us, and re-occupy their ancient haunts? Ever since I have attended to the subject of ornithology, I have always supposed that the sudden reverse of affection, that strange avriorogyn, which immediately succeeds in the feathered kind to the most passionate fondness, is the occasion of an equal dispersion of birds over the face of the earth. Without this provision, one favourite district would be crowded with inhabitants, while others would be destitute and forsaken. But the parent birds seem to maintain a jealous superiority, and to oblige the young to seek for new abodes; and the rivalry of the males in many kinds prevents their crowding the one on the other. Whether the swallows and house-martens return in the same exact number annually it is not easy to say, for reasons given above; but it is apparent, as I have remarked before in my Monographies, that the numbers returning bear no manner of proportion to the numbers retiring. * We do not mean to dispute the accuracy of the fact here mentioned; but we have seen many instances where the number of nests were trebled, during three or four years, in one locality. — ED. BOTANY. 217 LETTER LXXXII. TO THE HON. DAINES BARRINGTON. SELBORNE, June 2, 1778. DEAR SIR,- The standing objection to botany has always been, that it is a pursuit that amuses the fancy and exercises the memory, without improving the mind, or advancing any real knowledge; and, where the science is carried no farther than a mere systematic classification, the charge is but too true. But the botanist that is desirous of wiping off this aspersion, should be by no means content with a list of names; he should study plants philosophically, should investigate the laws of vegetation, should examine the powers and virtues of efficacious herbs, should promote their cultivation, and graft the gardener, the planter, and the husbandman on the phytologist. Not that system is by any means to be thrown aside-without system the field of Nature would be a pathless wilderness—but system should be subservient to, not the main object of, pursuit. Vegetation is highly worthy of our attention, and in itself is of the utmost consequence to mankind, and productive of many of the greatest comforts and elegancies of life. To plants we owe timber, bread, beer, honey, wine, oil, linen, cotton, &c.-what not only strengthens our hearts, and exhilarates our spirits, but what secures us from inclemencies of weather, and adorns our persons. Man, in his true state of nature, seems to be subsisted by spontaneous vegetation; in middle climes, where grasses prevail, he mixes some animal food with the produce of the field and garden; and it is towards the polar extremes only, that, like his kindred bears and wolves, he gorges himself with flesh alone, and is driven to what hunger has never been known to compel the very beasts,—to prey upon his own species.* The productions of vegetation have had a vast influence on the commerce of nations, and have been the great promoters of navigation, as may be seen in the articles of sugar, tea, tobacco, opium, ginseng, betel, pepper, &c. As every climate has its peculiar produce, our natural wants bring on a mutual intercourse; so that by means of trade, each distant part is supplied with the growth of every latitude. But, without the knowledge of plants and their culture, we must have been * See the late voyages to the South Seas. content with our nips and haws, without enjoying the delicate fruits of India, and the salutiferous drugs of Peru. Instead of examining the minute distinctions of every various species of each obscure genus, the botanist should endeavour to make himself acquainted with those that are useful. You shall see a man readily ascertain every herb of the field, yet hardly know wheat from barley, or at least one sort of wheat or barley from another.* : But of all sorts of vegetation, the grasses seem to be most neglected neither the farmer nor the grazier seem to distinguish the annual from the perennial, the hardy from the tender, nor the succulent and nutritive from the dry and juiceless. † The study of grasses would be of great consequence to a northerly and grazing kingdom. The botanist that could improve the sward of the district where he lived, would be a useful member of society to raise a thick turf on a naked soil, would be worth volumes of systematic knowledge; and he would be the best commonwealth's man that could occasion the growth of "two blades of grass where one alone was seen before." : LETTER LXXXIII. TO THE HON. DANIES BARRINGTON. SELBORNE, July 3, 1778. DEAR SIR,-In a district so diversified with such a variety of hill and dale, aspects and soils, it is no wonder that great choice of plants should be found. Chalks, clays, sands, sheepwalks and downs, bogs, heaths, woodlands, and champaign fields, cannot but furnish an ample flora. The deep rocky lanes abound with filices, and the pastures and moist woods with fungi. If in any branch of botany we may seem to be wanting, it must be in the large aquatic plants, which are not * The observations and experiments of one generation after another, have enabled us progressively to improve, by culture, the cereal grasses, into those valuable plants wheat and barley, which now maintain millions of our fellow men. -ED. + Of late not only the attention of the naturalist, but also of the farmer, has been directed to the study of grasses, to the preference of particular species, and to the relative produce of the different kinds. Among the works which have most contributed to the advancement of this highly important department of agriculture, we would mention Curtis on British Grasses, and the splendid and valuable Hortus Gramineus Woburnensis; and in Young's Farmer's Magazine many interesting experiments have been recorded. - ED. |