8. In November, 1819, black rain and snow fell in Canada.
9. On the 3d of May, 1831, red rain fell near Giessen. It deposited a dark-colored sediment which Dr. Zimmermann found to contain silica, oxide of iron, and various other substances observed in aerolites.
It is well known that quantities of sand are often conveyed, by the trade-winds, from the continent of Africa and deposited in the ocean. Such sand-showers have sometimes occurred several hundred miles from the coast. Volcanic matter also has been occasionally carried a considerable distance. The phenomena above described cannot, however, be referred to such causes; and there can be little doubt that most, if not all of them, were of meteoric origin.
There is, in all probability, a regular gradation from the smallest visible shooting-stars to bolides and aerolites. No doubt a great number of very small meteoric stones penetrate beneath the earth's surface and escape observation. An interesting account of the accidental discovery of such celestial pebbles has recently been given by Professor Haidinger, of Vienna. The meteor from which they were derived was but little larger than an ordinary shooting-star. Its track was visible, however, until it terminated at the earth's surface. Professor Haidinger's account is as follows: On the 31st of July, 1859, about half-past nine o'clock in the evening, three inhabitants of the bourg of Montpreis, in Styria, saw a small luminous globe, very similar to a shooting-star, and followed by a luminous streak in the heavens, fall directly to the earth, which it attained close to the château that exists in the locality. The fall was accompanied by a whistling or hissing noise in the air, and terminated by a slight detonation. The three observers, rushing to the spot where the meteor fell, immediately found a small cavity in the hard, sandy soil, from which they extracted three small meteoric stones about the size of nuts, and a quantity of black powder. For five to eight seconds these stones continued in a state of incandescence, and it was necessary to allow upwards of a quarter of an hour to elapse before they could be touched without inflicting a burn. They appear to have been ordinary meteoric stones, covered with the usual black rind. The possessors would not give them up to be analyzed. The details of this remarkable occurrence of the fall of an extremely small meteor, we owe to Herr Deschann, Conservator of the Museum of Laibach, in Carniola, and member of the Austrian Chamber of Deputies.
The following is perhaps the only instance on record in which a shooting-star lower than the clouds has been undoubtedly observed. The date is one at which meteors are said to be more than usually numerous; and the radiant point for the epoch has been recently determined, by British observers, to be about Gamma Cygni. The meteor was seen by Mr. David Trowbridge, of Hector, Schuyler County, New York, who says: "On the evening of July 26th, 1866, about 8h. 15m. P.M., a very bright meteor flashed out in Cygnus, and moved from east to west with great rapidity. Its path was about 30° after I saw it. Height above the northern horizon about 50°. Duration of flight from one-half to one second. It left a beautiful train. The head was red and train blue. It was certainly below the clouds. It passed between me and some cirro-stratus clouds, so dense as to hide ordinary stars completely. Several others that saw it said it was below the clouds."—Silliman's Journal for Sept. 1866. It seems altogether probable that when a meteor thus descends, before its explosion or dissipation, into the lower atmospheric strata, at least portions of its mass must reach the earth's surface.
Meteoric Transits—Dark Days.
If shooting-stars and aerolites are derived from meteoric rings revolving round the sun in orbits nearly intersecting that of the earth, then (1) these masses must sometimes transit the solar disk; (2) if any of the rings contain either individual masses of considerable magnitude, or sufficiently dense swarms of meteoric asteroids, such transits may sometimes be observed; (3) the passage of a dense meteoric cluster over the solar disk must partially intercept the sun's light and heat; and (4) should both nodes of the ring very nearly intersect the earth's orbit, meteoric falls might occur when the earth is at either; in which case the epochs would be separated by an interval of about six months. Have any such phenomena as those indicated been actually observed?
The passage of dark spots across the sun, having a much more rapid motion than the solar maculæ, has been frequently noticed. The following instances are well authenticated:
1779, June 17th. About mid-day the eminent French astronomer, Messier, saw a great number of black points crossing the sun. Rapidly moving spots were also seen by Pastorff on the following dates:
1822, October 23d,