On October 10, 1880, Lewis Swift, of Rochester, New York, discovered a comet which has proved to be of peculiar interest. From its first discovery it has presented no brilliancy of appearance, for, during its period of visibility, a telescope of considerable power was necessary to observe it. Since this comet, when in close proximity to the earth, was very faint indeed, its dimensions must be quite moderate.
The illustration on page 88 gives the orbit of the earth and the orbit of this comet, and shows how closely they approached each other; when at its nearest, the comet was only distant from the earth 0.13 of the distance of the earth from the sun.
It comes back in eleven years, or in 1891.
On the 22d of June, 1881, a comet of great brilliancy flashed suddenly into view. It was unexpected, and advanced with tremendous rapidity. The illustration on page 89 will show how its flight intersected the orbit of the earth. At its nearest point, June 19th, it was distant
{p. 88}
from the earth only 0.28 of the distance of the sun from the earth.
Now, it is to be remembered that great attention has been paid during the past few years to searching for comets, and some of the results are here given. As many as five were discovered during the year 1881. But not
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ORBIT OF EARTH AND COMET
a few of the greatest of these strange orbs require thousands of years to complete their orbits. The period of the comet of July, 1844, has been estimated at not less than one hundred thousand years!