for this unsettling opinion, and for maintaining that the moon is an
inhabited earth. He was defended by Pericles (432 B.C.).

Solon dabbled, like many others, in reforms of the calendar. The
common year of the Greeks originally had 360 days--twelve months of
thirty days. Solon's year was 354 days. It is obvious that these
erroneous years would, before long, remove the summer to January and
the winter to July. To prevent this it was customary at regular
intervals to intercalate days or months. Meton (432 B.C.) introduced a
reform based on the nineteen-year cycle. This is not the same as the
Egyptian and Chaldean eclipse cycle called _Saros_ of 223
lunations, or a little over eighteen years. The Metonic cycle is 235
lunations or nineteen years, after which period the sun and moon
occupy the same position relative to the stars. It is still used for
fixing the date of Easter, the number of the year in Melon's cycle
being the golden number of our prayer-books. Melon's system divided
the 235 lunations into months of thirty days and omitted every
sixty-third day. Of the nineteen years, twelve had twelve months and
seven had thirteen months.

Callippus (330 B.C.) used a cycle four times as long, 940 lunations,
but one day short of Melon's seventy-six years. This was more correct.

Eudoxus (406-350 B.C.) is said to have travelled with Plato in
Egypt. He made astronomical observations in Asia Minor, Sicily, and
Italy, and described the starry heavens divided into constellations.
His name is connected with a planetary theory which as generally
stated sounds most fanciful. He imagined the fixed stars to be on a
vault of heaven; and the sun, moon, and planets to be upon similar
vaults or spheres, twenty-six revolving spheres in all, the motion of