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sections of the country, the people were terrorstricken by the awful spectacle, and supposed that the end of the world had come.
An inferior shower was seen in 1831 and 1832; and so also in the succeeding years, until 1839. These did not compare in brilliancy with the remarkable phenomenon of 1833.
There was an interval of about 33 or 34 years between the great showers of 1799 and 1833; this seemed to indicate another shower in November, 1866. The people of both hemispheres were literally awake to the subject. Newspapers aroused the most sluggish imagination with thrilling accounts of the scenes presented in 1799 and 1833. Extempore observatories were founded in every convenient point. Watchmen were stationed, and the city bells were to be rung on the appearance of the first wandering celestial visitor. The exact night was not definitely known, but for fear of a mistake, the 11th, 12th, and 13th were generally observed. All painfully testify to those nights being clear and beautiful as moonlight and starlight could make them. The anxious vigils, the fruitless scannings of the sky, the disappointment, the meteors that were dimly thought to be seen—all these are recorded in the memory of the temporary astronomers of that year. While, however, the people of America were thus disappointed, there was being enacted in England a display brilliant indeed, though inferior to the one of
1833. The staff at Greenwich Observatory counted about 8,000 meteors; other observers, however, made a much lower estimate. Chambers, in describing the phenomena, says: "Of the large number of descriptions which came under my eye in manuscript and in print, the following is a fair example: 'From 11£ p. M. until 2 A. M. we were much interested in watching the shooting stars; anything so beautiful I never saw, especially about one o'clock, when they were most brilliant;' and so on by the ream." In November, 1867, the long-expected shower was seen in this country, but it failed to satisfy the public expectation. The sky was, however, illumined with shooting stars and meteors, some of which exceeded even Jupiter or Venus in brilliancy.
Number of meteors and shooting stars.—Prof. Newton, who has given much study to this subject, estimates that the average number of meteors that traverse the atmosphere daily, and which are large enough to be visible to the eye on a dark clear night, is 7,500,000; and if to these the telescopic meteors be added, the number would be increased to 400,000,000. In the space traversed by the earth there are, on the average, in each volume the size of our globe (including its atmosphere), as many as 13,000 small bodies, each one capable of furnishing a shooting star visible under favorable circumstances to the naked eye.
Annual periodicity of the star-showers.—On almost any clear night, from five to seven shooting stars may be seen per hour, but in certain months they are much more abundant. Arago names the following principal dates:
April 4^11; 17-25. October (abont) 15.
Origin.—Aerolites, meteors, and falling stars all seem to have a common origin. They are produced by small bodies—planets in miniature—which are revolving, like our earth, about the sun. Their orbits intersect the orbit of the earth, and if at any time they reach the point of crossing exactly with the earth, there is a collision. Their mass is so small, that the earth is not jarred any more than is a railway train by a pebble thrown against it.
These small bodies may come near the earth and be drawn to its surface by the power of attraction; or they may simply sweep through the higher regions of the atmosphere, and there escape its grasp; or, finally, they may, under certain conditions, be compelled to revolve many times around the earth as satellites. Indeed, a French astronomer estimates that there is one now circling, about the earth at a distance of 5,000 miles. This companion of our moon has a period of three hours and twenty minutes. The average velocity of these meteoric bodies or bolides, as they are frequently called, is thirty-six miles per second—much greater than that of Mercury itself. As they sweep through the air, the friction partly arrests their motion, and converts it into heat and light. The body thus becomes visible to us. Its size and direction determine its appearance. If very small, it is consumed in the upper regions, and leaves only the luminous trail of a shooting star. If of large size, it may sweep along at a high elevation, or plunge directly toward the ground. Becoming highly heated in its course, it sheds a vivid light, while, unequally expanding, it explodes, throwing off large fragments which fall to the earth as aerolites, or continue their separate course as meteors. The cinders of the portion consumed rain down on us as fine meteoric dust.
Meteorio Kings.—These little bodies, it is thought, do not generally revolve individually about the sun, but myriads of them are collected in several rings, and when the earth passes through one of these floating girdles, a star-shower follows. This would account for their regular appearance in certain seasons of the year. In the cut we see how one ring, intersecting the earth's orbit at two points, would account for the August and November showers. Another ring, more inclined to the earth's path, and crossing it nearer the aphelion point, would produce the April showers.
Recent investigators are inclined to the view that there are separate rings for each of the established periods, and that they are very elliptical. The November ring seems to have its perihelion near the ecliptic, and its aphelion beyond the orbit of Uranus; while the August ring extends beyond the solar system. The day of the month in which the great November shower occurs is becoming later at each re