The notions of the penumbra and umbra are important in considering eclipses (q.v.).
Among Lockyer's other works are - The Dawn of Astronomy (1894), to which Stonehenge and other British Stone Monuments astronomically considered (1906) may be considered a sequel; Recent and coming Eclipses (1897); and Inorganic Evolution (1900).
Further, we know that in the 8th century B.C., there were observatories in most of the large cities in the valley of the Euphrates, and that professional astronomers regularly took observations of the heavens, copies of which were sent to the king of Assyria; and from a cuneiform inscription found in the palace of Sennacherib at Nineveh, the text of which is given by George Smith,5 we learn that at that time the epochs of eclipses of both sun and moon were predicted as possible - probably by means of the cycle of 223 lunations or Chaldaean Saros - and that observations were made accordingly.
It is remarkable that no records of eclipses are known from Egyptian documents.
But that native land was too far off, and for a man going a thousand miles it is absolutely necessary to set aside his final goal and to say to himself: "Today I shall get to a place twenty-five miles off where I shall rest and spend the night," and during the first day's journey that resting place eclipses his ultimate goal and attracts all his hopes and desires.