The following, in relation to the freezing of the Ohio River, is evidence of a different kind, but shows the same general correspondence, and particularly the mildness of the winters when there were few spots, and their severity from 1836 to 1838, inclusive, when the spots were most numerous:
1829.—River open all winter—some floating ice.
1830.—River closed 27th January.
1831.—Floating ice—closed 23d January—opened 20th February.
1832.—Closed in December, which was a very cold month—opened January 8, and remained open all winter.
1833.—Open all winter.
1834.—Open all winter.
1835.—Closed January 6—opened the last of the month—cold.
1836.—Closed 28th January—opened 25th February.
1837.—Closed from 8th December to 8th February. Cold year.
1838.—Closed from 13th January to 13th March. Cold year.
1839.—Closed from 6th December to 13th January.
1840.—Closed 29th December—opened 15th January.
1841.—Closed 3d January—opened 8th do.
1842.—Open all winter.
1843.—Closed 28th November—opened 5th December—open all the rest of the winter.
1844.—Open all winter.
1845.—Open all winter.
1846.—Closed 5th December—opened again a few days—closed again on the 26th. It is not stated how long it remained closed.
1847.—Open all winter.
1848.—Much floating ice, but not closed—heavy rains and floods.
1849.—Floating ice in January, but not closed.
1850.—Floating ice, but not closed.
1851.—Open all winter—a little ice.
(December in the above table, means December previous).
This is more reliable as to the winter season than the tables of annual means—although the evidence they afford, making due allowance for the exceptions, is very striking.
I shall return to this part of the subject again.
But there is other evidence of the influence of these spots. Their connection with the irregular magnetic disturbance of the earth has been distinctly traced. Colonel Sabine, President of the British Association, in his opening address, September, 1852, after reviewing the recent discoveries in magnetism, says:—
“It is not a little remarkable that this periodical magnetic variation is found to be identical in period, and in epochs of maxima and minima, with the periodical variation in the frequency and magnitude of the solar spots, which M. Schwabe has established by twenty-six years of unremitting labor. From a cosmical connection of this nature, supposing it to be finally established, it would follow that the decennial period, which we measure by our magnetic instrument, is, in fact, a solar period, manifested to us, also, by the alternately increasing and decreasing frequency and magnitude of observations on the surface of the solar disc. May we not have in these phenomena the indication of a cycle, or period of secular change in the magnetism of the sun, affecting visibly his gaseous atmosphere or photosphere, and sensibly modifying the magnetic influence which he exercises on the surface of our earth?”—American Journal of Science, new series, vol. xiv. p. 438.
I think it may fairly be inferred, that although these spots do not occasion the “cold spells” and “hot spells,” and other transient peculiarities, they do materially affect the mean temperature of the year, and exert an obvious influence when at their maxima; and there is a tendency to an increase of the heat and dryness of summer, and the severity of winter, at the periods named, in our excessive climate, and a well-established connection between the spots and magnetic disturbances and variations.
Popular opinion has ever attributed to the moon a controlling effect upon the changes of the weather. If it be dry, a storm is expected when the moon changes; or if it be wet, dry weather. Such popular opinions are usually entitled to respect, and founded in truth. But every attempt to verify this opinion, by careful observation and registration, has failed. Weather-tables and lunar phases, compared for nearly one hundred years, show four hundred and ninety-one new or full moons attended by a change of the weather, and five hundred and nine without. The celebrated Olbers, after fifty years of careful observation and comparison, decided against it. So did the more celebrated Arago, at a more recent date—summing up the result of his observations by saying—“Whatever the progress of the sciences, never will observers, who are trustworthy and careful of their reputation, venture to foretell the state of the weather.” Still, the moon may influence the weather, though she may not effect changes at her syzygies or quadratures, and this subject should not be too summarily dismissed. That the moon can not effect changes at the periods named seems philosophically obvious. She changes, for the whole earth, within the period of twenty-four hours; yet, how varied the state of things on different portions of its surface. The equatorial belts of trades, and drought, and rains, cover from fifty to sixty degrees of its surface, and know nothing of lunar disturbance. The extra-tropical belt of rains and variable weather moves up in its season, uncovering 10°, or more, of latitude, and admitting the trades and a six months’ drought over it, as in California, regardless of the moon. Under the zone of extra-tropical rains, even upon the eastern part of the continent of North America, “dry spells” and “wet spells” exist side by side; the focus of precipitation is now in one parallel, and now in another—storms exist here and fair weather there, on the same continent at the same time; and as the moon’s rays in her northing pass round the northern hemisphere during the twenty-four hours, they, doubtless, pass from ten to thirty or more storms, of all characters and intensities, moving in opposition to her orbit—and as many larger intervening areas of fair weather, not one of which are indebted to her for their existence, or “take thought of her coming.”
The storm, which originates in the tropics, pursues its curving way now N. W., then N. E., and again north, to the Arctic circle, and, perhaps, around the magnetic pole, over gulf, and continent, and ocean, occupying one third the time of a lunation, and two changes, perhaps, in its progress, without any perceptible or conceivable influence from her. Yet every inhabitant of mother-earth, influenced by coincidences remembered, and uninfluenced by exceptions forgotten, looks up within his limited horizon, and devoutly expects from the agency of some phase of the moon, a change for the special benefit of his dot upon the earth’s surface. Upon how many of these countless dots is the moon at a particular phase, or relative distance from the sun, to change fair weather to foul, or foul to fair? Upon none. The storms keep on their way;—the wet spells, and the dry spells, the cold and the hot spells alternate in their time, and though the moon turns toward them in passing, her dark face, her half face, or her full orb (the gifts of the sun, which confer no power), they do not heed her. They are originated, and are continued, by a more potent agent. They are the work of an atmospheric mechanism, as ceaseless in its operation as time, as regular as the seasons, as extensive as the globe.
Indeed, it seems as if it was expressly designed by the Creator that the moon should not interfere materially with this atmospheric machinery. She is the nearest orb; her influence would be controlling and continuous; would follow her monthly path from south to north, and with changes too violent, and intervals too long; and would interfere with the regular fundamental operation in the trade-wind region, where she is vertical. Aside from the attraction of gravitation, therefore, she seems to have been so created as to be incapable of exerting any influence. She is without an atmosphere; the rays which she reflects are polarized, and without chemical or magnetic power; and, if it be true that Melloni has recently detected heat in them, by the use of a lens three feet in diameter, which could not previously be effected, its quantity is exceedingly small, and incapable of influence. Doubtless, the attraction of her mass is felt upon the earth, as the tides attest; and upon the atmosphere as well as the ocean. But the atmosphere is comparatively attenuated, and exceedingly so at its upper surface. Her attraction, therefore, although felt, is not influential. She seemed, to Dr. Howard, to produce in her northing and southing, a lateral tide which the barometer disclosed, but owing to the attenuated character of the atmosphere, neither the sun nor moon create an easterly and westerly tide, that is observable, except with the most delicate instruments. Sabine is believed to have detected such a tide by the barometer, at St. Helena, of one four thousandth of an inch. But even this infinitesimal influence may prove an error upon further investigation. There is a diurnal variation of the barometer, but it is not the result of her attraction, for it is not later each day as are the tides, exists in the deepest mines as well as upon the surface, and is demonstrably connected with the group of diurnal changes produced by the action of the sun-light and heat upon the earth’s magnetism.