Poiet.—I have often observed, that when the swallows fly high, fine weather is to be expected or continued; but when they fly low, and close to the ground, rain is almost surely approaching. Can you account for this?
Hal.—Swallows follow the flies and gnats, and flies and gnats usually delight in warm strata of air; and as warm air is lighter, and usually moister, than cold air, when the warm strata of air are high, there is less chance of moisture being thrown down from them by the mixture with cold air; but when the warm and moist air is close to the surface, it is almost certain, that, as the cold air flows down into it, a deposition of water will take place.
Poiet.—I have often seen sea-gulls assemble on the land, and have almost always observed, that very stormy and rainy weather was approaching. I conclude, that these animals, sensible of a current of air approaching from the ocean, retire to the land to shelter themselves from the storm.
Orn.—No such thing. The storm is their element; and the little petrel enjoys the heaviest gale, because, living on the smaller sea insects, he is sure to find his food in the spray of a heavy wave—and you may see him flitting above the edge of the highest surge. I believe, that the reason of this migration of seagulls, and other sea birds, to the land, is their security of finding food. They may be observed, at this time, feeding greedily on the earth worms and larvæ, driven out of the ground by severe floods; and the fish, on which they prey in fine weather in the sea, leave the surface, when storms prevail and go deeper. The search after food, as we agreed on a former occasion, is the principal cause why animals change their places. The different tribes of the wading birds always migrate when rain is about to take place; and I remember once, in Italy, having been long waiting, in the end of March, for the arrival of the double snipe in the Campagna of Rome,—a great flight appeared on the 3d of April, and the day after heavy rain set in, which greatly interfered with my sport. The vulture, upon the same principle, follows armies; and I have no doubt, that the augury of the ancients was a good deal founded upon the observation of the instincts of birds. There are many superstitions of the vulgar owing to the same source. For anglers, in spring, it is always unlucky to see single magpies,—but two may be always regarded as a favourable omen; and the reason is, that in cold and stormy weather one magpie alone leaves the nest in search of food, the other remaining sitting upon the eggs or the young ones; but when two go out together, the weather is warm and mild, and thus favourable for fishing.
Poiet.—The singular connexions of causes and effects, to which you have just referred, make superstition less to be wondered at, particularly amongst the vulgar; and when two facts, naturally unconnected, have been accidentally coincident, it is not singular that this coincidence should have been observed and registered, and that omens of the most absurd kind should be trusted in. In the west of England, half a century ago, a particular hollow noise on the sea coast was referred to a spirit or goblin, called Bucca, and was supposed to foretel a shipwreck: the philosopher knows, that sound travels much faster than currents in the air—and the sound always foretold the approach of a very heavy storm, which seldom takes place on that wild and rocky coast, surrounded as it is by the Atlantic, without a shipwreck on some part of its extensive shores.
Phys.—All the instances of omens you have mentioned are founded on reason; but how can you explain such absurdities as Friday being an unlucky day, the terror of spilling salt, or meeting an old woman? I knew a man, of very high dignity, who was exceedingly moved by these omens, and who never went out shooting without a bittern’s claw fastened to his buttonhole by a ribband—which he thought ensured him good luck.
Poiet.—These, as well as the omens of death watches, dreams, &c., are for the most part founded upon some accidental coincidences; but spilling of salt, on an uncommon occasion, may, as I have known it, arise from a disposition to apoplexy, shown by an incipient numbness in the hand, and may be a fatal symptom; and persons, dispirited by bad omens, sometimes prepare the way for evil fortune; for confidence in success is a great means of ensuring it. The dream of Brutus, before the field of Philippi, probably produced a species of irresolution and despondency, which was the principal cause of his losing the battle: and I have heard, that the illustrious sportsman, to whom you referred just now, was always observed to shoot ill, because he shot carelessly, after one of his dispiriting omens.
Hal.—I have in life met with a few things, which I found it impossible to explain, either by chance coincidences or by natural connexions; and I have known minds of a very superior class affected by them,—persons in the habit of reasoning deeply and profoundly.
Phys.—In my opinion, profound minds are the most likely to think lightly of the resources of human reason: it is the pert, superficial thinker who is generally strongest in every kind of unbelief. The deep philosopher sees chains of causes and effects so wonderfully and strangely linked together, that he is usually the last person to decide upon the impossibility of any two series of events being independent of each other; and in science, so many natural miracles, as it were, have been brought to light,—such as the fall of stones from meteors in the atmosphere, the disarming a thunder cloud by a metallic point, the production of fire from ice by a metal white as silver, and referring certain laws of motion of the sea to the moon,—that the physical inquirer is seldom disposed to assert, confidently, on any abstruse subjects belonging to the order of natural things, and still less so on those relating to the more mysterious relations of moral events and intellectual natures.