marked diminution, the effect must of necessity be increased at each
return, and after only a few, possibly one or two, circuits, the
comet will be absorbed by the sun."

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