SIR HUMPHRY DAVY ON WEATHER-OMENS.
In his shepherd’s calling he was prompt,
And watchful more than ordinary men.
Hence had he learned the meaning of all winds,
Of blasts of every tone; and oftentimes,
When others heeded not, he heard the South
Make subterraneous music, like the noise
Of bagpipes upon distant Highland hills.
The late Sir Humphry Davy, one of the most successful modern explorers of the secrets of nature, was not above attending to, and explaining, the “weather-omens” which are derived from popular observation.
In his Salmonia he has the following dialogue between Haliens, (a fly-fisher,) Poietes, (a poet,) Physicus, (a man of science,) and Ornither, (a sportsman):—
Poiet.—I hope we shall have another good day to-morrow, for the clouds are red in the west.
Phys.—I have no doubt of it, for the red has a tint of purple.
Hal.—Do you know why this tint portends fine weather?
Phys.—The air, when dry, I believe, refracts more red, or heat-making rays; and as dry air is not perfectly transparent, they are again refracted in the horizon. I have generally observed a coppery or yellow sunset to foretell rain; but as an indication of wet weather approaching, nothing is more certain than a halo round the moon, which is produced by precipitated water; and the larger the circle, the nearer the clouds, and consequently the more ready to fall.
Hal.—I have often observed that the old proverb is correct,—
A rainbow in the morning is the shepherd’s warning;
A rainbow at night is the shepherd’s delight.
Can you explain this omen?
Phys.—A rainbow can only occur when the clouds containing or depositing the rain are opposite the sun,—and in the evening the rainbow is in the east, and in the morning in the west; and as our heavy rains, in this climate, are usually brought by the westerly wind, a rainbow in the west indicates that the bad weather is on the road, by the wind, to us; whereas the rainbow in the east proves that the rain in those clouds is passing from us.
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 sea-gulls, and other sea-birds, to the land, is their security of finding food; and 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, and go deeper, in storms. The search after food, as we have 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 favorable 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 it is only when the weather is warm and mild, and favorable for fishing.
Poiet.—The singular connections 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 foretell 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 without a shipwreck on some part of its extensive shores, surrounded by the Atlantic.