III.  Luminous gases surround the nucleus.

IV.  The drift-clays are the result of the grinding up of granitic rocks.

V. No such deposits, of anything like equal magnitude, could have been formed on the earth.

[1.  “The Great Ice Age,” p. 13.]

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VI.  No such clays are now being formed under glaciers or Arctic ice-sheets.

VII.  These clays were ground out of the substance of the comet by the endless changes of position of the material of which it is composed as it flew through space, during its incalculable journeys in the long reaches of time.

VIII.  The earth-supplies of gravel are inadequate to account for the gravel of the drift-deposits.

IX.  Neither sea-beach nor rivers produce stones like those found in the Drift.

I pass now to the next question.

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CHAPTER III.

COULD A COMET STRIKE THE EARTH?

READER, the evidence I am about to present will satisfy you, not only that a comet might have struck the earth in the remote past, but, that the marvel is that the earth escapes collision for a single century, I had almost said for a single year.

How many comets do you suppose there are within the limits of the solar system (and remember that the solar system occupies but an insignificant portion of universal space)?

Half a dozen-fifty-a hundred-you will answer.

Let us put the astronomers on the witness-stand: 

Kepler affirmed that “COMETS ARE SCATTERED THROUGH THE HEAVENS WITH
AS MUCH PROFUSION AS FISHES IN THE OCEAN.”

Think of that!

“Three or four telescopic comets are now entered upon astronomical records every year.  Lalande had a list of seven hundred comets that had been observed in his time.”

Arago estimated that the comets belonging to the solar system, within the orbit of Neptune, numbered seventeen million five hundred thousand!

Lambert regards five hundred millions as a very moderate estimate![1]

[1.  Guillemin, “The Heavens,” p. 251.]

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And this does not include the monstrous fiery wanderers who may come to visit us, bringing their relations

###

ORBITS OF THE PERIODIC COMETS.

along, from outside the solar system—­a sort of celestial immigrants whom no anti-Chinese legislation can keep away.

Says Guillemin: 

“Leaving mere re-appearances out of the question, new comets are constantly found to arrive from the depths of space, describing around the sun orbits which testify to the attractive power of that radiant body; and, for the

{p. 84}

most part, going away for centuries, to return again from afar after their immense revolutions."[1]

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