Ragnarok : the age of fire and gravel

84 THE COMET.

most part, going away for centuries, to return again from afar after their immense revolutions.” *

But do these comets come anywhere near the orbit of the earth ?

Look at the map on the preceding page, from Amédée Guillemin’s great work, “The Heavens,” page 244, and you can answer the question for yourself.

Here you see the orbit of the earth overwhelmed in a complication of comet-orbits. The earth, here, is like a lost child in the midst of a forest full of wild beasts.

And this diagram represents the orbits of only six comets out of those seventeen millions or five hundred millions !

It is a celestial game of ten-pins, with the solar sys-

tem fora bowling-alley, and the earth waiting for a tenstrike. In 1832 the earth and Biela’s comet, as I will show more particularly hereafter, were both making for the same spot, moving with celestial rapidity, but the comet reached the point of junction one month before the earth did; and, as the comet was not polite enough to wait for us to come up, this generation missed a reyelation. “Tn the year 1779 Lexell’s comet approached so near to the earth that it would have increased the length of the sidereal year by three hours if its mass had been equal to the earth’s.” +

And this same comet did strike our fellow-planet, Jupiter.

* “The Heavens,” p. 251. + “Edinburgh Review,” October, 1874, p. 205.