The Writings of Thomas Jefferson: Library Edition - Vol. 6 (of 20)Jefferson, Thomas
History
The Writings of Thomas Jefferson: Library Edition - Vol. 6 (of 20)
Jefferson, Thomas
United States -- Politics and government -- 1775-1783; United States -- Politics and government -- 1783-1789
the millions of ages necessary to form itself? That when it had done
this, he stepped in a second time, to create the animals and plants
which were to inhabit it? As the hand of a creator is to be called in,
it may as well be called in at one stage of the process as another. We
may as well suppose he created the earth at once, nearly in the state
in which we see it, fit for the preservation of the beings he placed on
it. But it is said, we have a proof that he did not create it in its
present solid form, but in a state of fluidity; because its present
shape of an oblate spheroid is precisely that which a fluid mass
revolving on its axis would assume.
I suppose that the same equilibrium between gravity and centrifugal
force, which would determine a fluid mass into the form of an oblate
spheroid, would determine the wise creator of that mass, if he made it
in a solid state, to give it the same spheroidical form. A revolving
fluid will continue to change its shape, till it attains that in which
its principles of contrary motion are balanced. For if you suppose them
not balanced, it will change its form. Now, the same balanced form is
necessary for the preservation of a revolving solid. The creator,
therefore, of a revolving solid, would make it an oblate spheroid, that
figure alone admitting a perfect equilibrium. He would make it in that
form, for another reason; that is, to prevent a shifting of the axis of
rotation. Had he created the earth perfectly spherical, its axis might
have been perpetually shifting, by the influence of the other bodies of
the system; and by placing the inhabitants of the earth successively
under its poles, it might have been depopulated; whereas, being
spheroidical, it has but one axis on which it can revolve in
equilibrio. Suppose the axis of the earth to shift forty-five degrees;
then cut it into one hundred and eighty slices, making every section in
the plane of a circle of latitude, perpendicular to the axis: every one
of these slices, except the equatorial one, would be unbalanced, as
there would be more matter on one side of its axis than on the other.
There could be but one diameter drawn through such a slice, which would
divide it into two equal parts. On every other possible diameter, the
parts would hang unequal. This would produce an irregularity in the
diurnal rotation. We may, therefore, conclude it impossible for the
poles of the earth to shift, if it was made spheroidically; and that it
would be made spheroidical, though solid, to obtain this end. I use
this reasoning only on the supposition that the earth has had a
beginning. I am sure I shall read your conjectures on this subject with
great pleasure, though I bespeak, beforehand, a right to indulge my
natural incredulity and scepticism. The pain in which I write awakens
me here from my reverie, and obliges me to conclude with compliments to
Mrs. Thompson, and assurances to yourself of the esteem and affection
Public-domain text, read in full here on John Shaqi.
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