suggestion comes from the heavenly bodies. With the increasing study
of the nebulae, many forms of these interesting bodies have been
discovered. A very common type consists of a great coherent central
mass, with two or more arms extending from opposite sides in the form
of a spiral. This is as if gaseous revolving nebulae had come into
comparatively close proximity to a passing body. The visitor, by its
attraction, drew from the nebula a wisp of gas. The revolving motion
of the nebula gave to the attracted arm the spiral form.

These twisted arms are not equally dense throughout, but have
thickened knots here and there in their course. The Planetesimal
Theory suggests that these thickened knots are embryo planets and the
central portion of the nebulae an embryo sun. After all the material in
such a body has condensed either around the knots or about the central
mass a new solar system will be complete. As before stated, neither of
these theories can be said to be demonstrated. Each of them has points
in its favor and each has its difficulties. It is pleasant to know
what men have clearly thought concerning such questions, but for a man
not a trained geologist neither will carry much conviction. He will
still rest with his own early conclusion that whichever shall prove to
be true, for him his old formula is still valid, "in the beginning God
made the heavens and the earth." He will no longer think of God as
having shaped the balls with his own hand and thrown them into space;
he will no longer dream that it all occurred within a week not more
than six thousand years ago; but still to him will come the reverent
conviction that, whatever the plan by which it was accomplished, it
was still God's plan and God carried it out.

Now that we have tried to stretch our imagination back to the origin
of our globe, the question not unnaturally comes to our mind, how long
ago did all this happen? Is there any possible means of telling when
the history of the earth began? All such attempts lead either to
indefinite or to uncertain conclusions. Each man who essays the
problem approaches it from a different side and ends with a different
result. But no matter what the method of approach, all are agreed on
at least one point, the enormous length of time, as counted in years,
through which the earth has lasted.

One great mathematician worked on the basis of the rate of the present
cooling of the earth. Counting backward to the time