ectar had reached thus far, it was immortal, and rose to
the sky. "From that time hath arisen a long-standing quarrel between
Rahu's head and the sun and moon," and the head swallows them from time
to time, causing eclipses. Rahu's head marks the ascending, Ketu, the
tail, the descending node.

This myth is very instructive. Before it could have arisen, not only
must the constellations have been mapped out, and the equator and
ecliptic both recognized, but the inclination of the moon's orbit to
that of the sun must also have been recognized, together with the fact
that it was only when the moon was near its node that the eclipses,
either of the sun or moon, could take place. In other words, the cause
of eclipses must have been at one time understood, but that knowledge
must have been afterwards lost. We have seen already, in the chapter on
"The Deep," that the Hebrew idea of _teh[=o]m_ could not possibly have
been derived from the Babylonian myth of _Tiamat_, since the knowledge
of the natural object must precede the myth founded upon it. If,
therefore, Gen. i. and the Babylonian story of Creation be connected,
the one as original, the other as derived from that original, it is the
Babylonian story that has been borrowed from the Hebrew, and it has
been degraded in the borrowing.

So in this case, the myth of the Dragon, whose head and tail cause
eclipses, must have been derived from a corruption and misunderstanding
of a very early astronomical achievement. The myth is evidence of
knowledge lost, of science on the down-grade.

Some may object that the myth may have brought about the conception of
the draconic constellations. A very little reflection will show that
such a thing was impossible. If the superstition that an eclipse is
caused by an invisible dragon swallowing the sun or moon had really been
the origin of the constellational dragons, they would certainly have all
been put in the zodiac, the only region of the sky where sun or moon can
be found; not outside it, where neither can ever come, and in
consequence where no eclipse can take place. Nor could such a
superstition have led on to the discoveries above-mentioned: that the
moon caused eclipses of the sun, the earth those of the moon; that the
moon's orbit was inclined to the ecliptic, and that eclipses took place
only near the nodes. The idea of an unseen spiritual agent being at work
would prevent any search for a physical explanation, since polytheism