We may feel tolerably sure that the period when the old southern constellations were formed must have been between 2400 and 2000 years before the present era, a period, by the way, including the date usually assigned to the deluge,--which, however, must really occupy our attention no further. In fact, let us leave the watery constellations lying below the equator of those remote times and seek at once the highest heavens above them. Here, at the northern pole of these days, we find the great Dragon, which in any astrological temple of the time must have formed the highest or crowning constellation, surrounding the very key-stone of the dome. He has fallen away from that proud position since. In fact, even 4000 years ago he only held to the pole, so to speak, by his tail, and we have to travel back 2000 years or so to find the pole situate in a portion of the length of the Dragon which can be regarded as central. One might almost, if fancifully disposed, recognise the gradual displacement of the Dragon from his old place of honour, in certain traditions of the downfall of the great Dragon whose 'tail drew the third part of the stars of heaven.' The central position of the Dragon, for even when the pole-star had drawn near to the Dragon's tail the constellation was still central, will remind the classical reader of Homer's description of the Shield of Hercules-- The scaly horror of a dragon, coil'd Full in the central field, unspeakable, With eyes oblique retorted, that ascant Shot gleaming fire. (_Elton's translation._) I say Homer's description, for I cannot understand how any one who compares together the description of the Shield of Achilles in the Iliad and that of the Shield of Hercules in the fragmentary form in which we have it, can doubt for a moment that both descriptions came from the same hand. (The theory that Hesiod composed the latter poem can scarcely be entertained by any scholar.) As I long since pointed out in my essay 'A New Theory of Achilles' Shield' ('Light Science,' first series), no poet so inferior as actually to borrow Homer's words in part of the description of the Shield of Hercules could have written the other parts not found in the Shield of Achilles. 'I cannot for my own part entertain the slightest doubt'--that is to say, I think it altogether probable--that Homer composed the lines supposed to describe the Shield of Hercules long before he introduced the description, pruned and strengthened, into that particular part of the Iliad where it served his purpose best. And I have as little doubt that the original description, of which we only get fragments in either poem, related to something far more important than a shield. The constellations are not suitable adornments for the shield of fighting man, even though he was under the special care of a celestial mother and had armour made for him by a celestial smith. Yet we learn that Achilles' shield displayed--