We now return to the western part of the sky, where we see, beyond Eridanus, the vast expanse covered by the constellation Cetus, the “Whale.” The head lies on and over the equator above the western bend of Eridanus. It is marked by a striking group of stars, of which Alpha (α), or Menkar, the “Nose,” is the chief. The star Gamma (γ) is a fine double; colors yellow and blue; distance 2″.5. Below and toward the west will be found Omicron (ο), better known by its popular title of Mira, the “Wonderful.” In some respects this is the most extraordinary of all variable stars. It excited great astonishment when its variations were first recorded in the seventeenth century. Most of the time it is entirely invisible to the naked eye; but once in about ten months it begins to brighten, and in a few weeks becomes conspicuous, sometimes equalling the second magnitude in brightness. Then it fades again, and in about three months disappears from naked-eye vision, although it is never lost to the telescope, which follows it down to the ninth magnitude, at which it remains, glowing redly, for several successive months. Its variations are more or less irregular both in period and in brightness. The causes are only conjectural. About all that we can say is that here is a sun which once every ten months blazes up to a thousand or fifteen hundred times its ordinary brilliancy. The imagination can work its will with such a star as that. The western part of Cetus is marked by a striking group of stars shaped something like the bowl of an upturned dipper and by a lone, bright star still farther west, Beta (β), or Deneb Kaitos, the “Tail of the Whale.” Above Cetus runs the long line of stars composing the constellation Pisces, now the leader of the zodiac, since it contains the Vernal Equinox. Alpha (α), or Al Rischa, the “Cord,” because it marks the ribbon imagined to bind two fishes together by their tails, is directly under the stars marking the head of Aries, to which we have already referred. It is a double of very singular colors--green and blue. The distance is about 3″.6. From Al Rischa the stars of the constellation stream northward to the figure of the Northern Fish, whose nose touches Andromeda, and westward to the Western Fish, which is situated under the Great Square of Pegasus. The extraordinary tendency of the stars of Pisces to run in streaming lines has been spoken of in Chapter III.