Page:Popular Science Monthly Volume 18.djvu/558
from which he would gladly escape—when we see these things, are we not reminded of the phylloxera which can taint the goblet in the hand of a king, of the secret foe which silently saps the health of cities, and that confusion of life and death, which, flying upon the wings of the wind, affronts the stablest security and makes a jest of human conservatism?
By Professor DANIEL KIRKWOOD.
WHEN the coincidence between the orbits of the November meteors and the comet of 1866 was first clearly established a few years since, it was supposed by astronomers that the so-called Leonids formed a single cluster, diffused through an arc of such length as to require three or four years to make its perihelion passage. The meteoric period was shown by Professor Newton, of Yale College, and J, C, Adams, of Cambridge University, to be thirty-three and one fourth years. Consequently, no further displays were expected from this stream till about the close of the century. But in "Nature" for June 3, 1875, numerous facts were given, all indicating the existence of a second group, less dense in its structure, and preceding the principal swarm by twelve or thirteen years. Again, the large number of meteors seen in 1879, taken in connection with the fact that, according to Humboldt, meteors were seen in unusual abundance just thirty-three years before, viz., in 1846, suggested the probable existence of a third and perhaps still smaller cluster, passing its perihelion about 1879-'80. It was felt to be important, therefore, that in case any considerable number of meteors should be visible this year at the November epoch, the shower should be observed and the facts recorded. Accordingly, I requested Professor D. E . Hunter, Principal of the Washington (Indiana) High School, to keep watch on the mornings of November 13th, 14th, and 15th. Professor Hunter has made a comprehensive report, which I have somewhat abridged in the following statement. The morning of the 13th was cloudy, and on the 15th the moon shone brightly till daybreak. The watch was consequently restricted to the morning of the 14th. Four observers were occupied from 3h 45m to 5h 45m—precisely two hours. The position was on a hill south of Washington, where the view was unobstructed, except on the south. One hundred and sixteen meteors were counted, ninety-one of which were conformable to the radiant in Leo. During the first hour the atmosphere was hazy and the moon interfered with the observations. The second hour was clear and moonless. The following table includes only Leonids, giving the number counted in every five minutes: