Thus, too, may we form some idea of
the latitude in which the first observers lived. For in high latitudes
the southernmost of the old constellations would not have been visible
at all, and in latitudes much lower than a certain latitude, presently
to be noted, these constellations would have ridden high above the
southern horizon, other star-groups showing below them which were not
included among the old constellations.

I have before me as I write a picture of the southern heavens, drawn by
myself, in which this vacant space--eccentric in position but circular
in shape--is shown. The centre lies close by the Lesser Magellanic
cloud--between the stars Kappa Toucani and Eta Hydri of our modern maps,
but much nearer to the last named. Near this spot, then, we may be sure,
lay the southern pole of the star-sphere when the old constellations, or
at least the southern ones, were invented. (If there had been
astronomers in the southern hemisphere Eta Hydri would certainly have
been their pole-star.)

Now it is a matter of no difficulty whatever to determine the epoch when
the southern pole of the heavens was thus placed.[57] Between 2100 and
2200 years before the Christian era the southern constellations had the
position described, the invisible southern pole lying at the centre of
the vacant space of the star-sphere--or rather of the space free from
constellations. It is noteworthy that for other reasons this period, or
rather a definite epoch within it, is indicated as that to which must be
referred the beginning of exact astronomy. Amongst others must be
mentioned this--that in the year 2170 B.C. _quam proxime_, the Pleiades
rose to their highest above the horizon at noon (or technically made
their noon culmination), at the spring equinox. We can readily
understand that to minds possessed with full faith in the influence of
the stars on the earth, this fact would have great significance. The
changes which are brought about at that season of the year, in reality,
of course, because of the gradual increase in the effect of the sun's
rays as he rises higher and higher above the celestial equator, would be
attributed, in part at least, to the remarkable star-cluster coming then
close by the sun on the heavens, though unseen. Thus we can readily
understand the reference in Job to the 'sweet influences of the
Pleiades.' Again at that same time, 2170 B.C. when the sun and the
Pleiades opened the year (with commencing spring) t