Here is a symbol of tremendous antiquity which is
worthy of notice. It is borne on the Korean ensign and merchant flag,
and has been adopted as a trade sign by the Northern Pacific Railroad
Company, though probably few are aware that it is the Great Monad, as
shown in the sketch below. This sign is to the Chinaman what the cross
is to the Christian. It is the sign of Deity and eternity, while the
two parts into which the circle is divided are called the Yin and the
Yan—the male and female forces of nature. A writer on the
subject more than three thousand years ago is reported to have said in
reference to it: "The illimitable produces the great extreme. The great
extreme produces the two principles. The two principles produce the
four quarters, and from the four quarters we develop the quadrature of
the eight diagrams of Feuh-hi." I hope readers will not ask me to
explain this, for I have not the slightest idea what it means. Yet I am
persuaded that for ages the symbol has had occult and probably
mathematical meanings for the esoteric student.

I will introduce the Monad in its elementary form.
Here are three easy questions respecting this great symbol:—

(I.) Which has the greater area, the inner circle
containing the Yin and the Yan, or the outer ring?

(II.) Divide the Yin and the Yan into four pieces
of the same size and shape by one cut.

(III.) Divide the Yin and the Yan into four pieces
of the same size, but different shape, by one straight cut.

See answer