Dew is an indication of fine weather, so is fog. Neither of these two formations occur under an overcast sky, or when there is much wind. One sees fog occasionally rolled away as it were by wind, but seldom or never formed while it is blowing.
Remarkable clearness of atmosphere near the horizon: distant objects, such as hills unusually visible, or raised (by refraction), and what is called “a good hearing day,” may be mentioned among signs of wet, if not wind, to be expected.
More than usual twinkling of the stars; indistinctness or apparent multiplication of the moon’s horns; halos; “winddogs,” and the rainbow; are more or less significant of increasing wind, if not approaching rain, with or without wind.
Mr. Glaisher remarks, in the account of one of his recent balloon ascents:—“It would also seem that, when the sky is overcast and no rain falling, the Sun is shining on its upper surface, and both these conclusions agree with all my own experiences. That double strata or layers of clouds are indications of rain is shown by my recent observations; but it is one of those facts which have so far attracted the attention of some observers of nature as even to have passed into proverbs. My friend, Mr. Sopwith, tells me that in the mining districts, where he has resided so much, it is a common saying that ‘it will be rain to-day; the clouds is twee ply thick;’ by which, in their homely phrase, they clearly express that their expectations of rain are based on the observance of one range of clouds flying in the air at a higher elevation than another.”
It has been well observed that the old lunar theory, still implicitly received by country-folks, and held by many ladies as a fact of direct experience—the theory that weather is apt to change at the moon’s quarters, clearly applies rather to the earth than to any particular spot on it. And all the various complicated forms of that theory, invented to supply its apparent failures—such as that a change from fine to wet may be expected if the new quarter is entered on after midnight, and vice versâ for a post-meridian change,—are liable to the same objection.
The late Marshal Bugeaud, says the Emancipation, when only a captain, during the Spanish campaign under Napoleon I., once read in a manuscript which by chance fell into his hands, that from observations made in England and Florence during a period of fifty years, the following law respecting the Weather had been proved true:—‘Eleven times out of twelve the weather remains the same during the whole moon as it is on the fifth day, if it continues unchanged over the sixth day; and nine times out of twelve like the fourth day, if the sixth resembles the fourth.’ From 1815 to 1830 M. Bugeaud devoted his attention to agriculture; and guided by the law just mentioned, avoided the losses in hay time and vintage which many of his neighbours experienced. When Governor of Algiers, he never entered on a campaign till after the sixth day of the moon. His neighbours at Excideuil and his lieutenants in Algeria would often exclaim, ‘How lucky he is in the weather.’ What they regarded as mere chance was the result of observation. In counting the fourth and sixth days, he was particular in beginning from the exact time of new moon, and added three-quarters of an hour for each day for the greater length of the lunar as compared with the solar day.
Mr. Shepherd, C.E., appears to prefer the planet Jupiter to the moon, and has discovered an elaborate law for the variations of our English weather, except so far as the principle is affected by comets.
Mr. Shepherd is not quite without even higher authority. Sir John Herschel has publicly intimated his suspicion that the periodic expansion in the Sun’s spots had some close connexion with the extraordinarily wet summer of 1860, and in his article on Meteorology in the Encyclopædia Britannica, the same eminent authority has connected this periodic change in the Sun’s spots, which takes place in about twelve years, with the periodic time of Jupiter’s revolution round the sun (which is nearly the same in length), so that here we have an eminent astronomer half conceding the same very dubious principle—that causes which affect equally, if not the whole earth, at least all places which, in the diurnal rotation, are brought into the same relative position towards the sun or the planet, are the principal influences which determine our local weather.
Yet, if this be so, how does it happen that the year 1860, which was abnormally wet in Europe, was abnormally dry in many other parts of the world? If Mr. Shepherd be right in connecting this fact with the orbital position of Jupiter, or Sir John Herschel in connecting it with the large spots on the Sun, it would scarcely have merely affected the local distribution of heat; or, if it could, the means by which these causes rob England to burn India remain as dark as before.—Paper in the Spectator newspaper.