building. They may have been destined to record great Time itself, great
Time that circles forever through the circling years. There is first the
year to be recorded, with its revolving days; white winter gleaming into
spring; summer reddening and fading to autumn. Returning winter tells
that the year has gone full circle; the sun among the stars gives the
definite measure of the days. A ring of thirty-six great boulders, set
ten paces apart, would give the measure of the year in days; and of
circles like this there are more than one.

In this endless ring of days the moon is the measurer, marking the hours
and weeks upon the blue belt of night studded with golden stars. Moving
stealthily among the stars, the moon presently changes her place by a
distance equal to her own breadth; we call the time this takes an hour.
From her rising to her setting, she gains her own breadth twelve times;
therefore, the night and the day are divided each into twelve hours.
Meanwhile she grows from crescent to full disk, to wane again to a
sickle of light, and presently to lose herself in darkness at new moon.
From full moon to full moon, or from one new moon to another, the
nearest even measure is thirty days; a circle of thirty stones would
record this, as the larger circle of thirty-six recorded the solar year.
In three years there are thrice twelve full moons, with one added; a
ring of thirty-seven stones representing this would show the simplest
relation between sun and moon.

The moon, as we saw, stealthily glides among the fixed stars, gaining
her own width every hour. Passing thus along the mid belt of the sphere,
she makes the complete circuit in twenty-seven days, returning to the
same point among the stars, or, if it should so happen, to the same
star, within that time. Because the earth has meanwhile moved forward,
the moon needs three days more to overtake it and gain the same relative