Close to the star ζ, the middle star of the "tail" of Ursa Major (or handle of the "Plough"), is a small star known as Alcor, which is easily visible to good eyesight without optical aid. It is mentioned by Al-Sufi, who says the Arabians called it _al-suha_, "the little unnoticed one." He says that "Ptolemy does not mention it, and it is a star which seems to test the powers of the eyesight." He adds, however, an Arabian proverb, "I show him _al-suha_, and he shows me the moon," which seems to suggest that to some eyes, at least, it was no test of sight at all. It has, however, been suspected of variation in light. It was rated 5th magnitude by Argelander, Heis, and Houzeau, but was measured 4·02 at Harvard Observatory. It has recently been found to be a spectroscopic binary. The constellation of the Dragon (Draco) is probably referred to in Job (chap. xxvi. v. 13), where it is called "the crooked serpent." In the Greek mythology it is supposed to represent the dragon which guarded the golden apples in the Garden of the Hesperides. Some have suggested that it represented the serpent which tempted Eve. Dryden says, in his translation of Virgil-- "Around our Pole the spiry Dragon glides, And like a wand'ring stream the Bears divides." The fact that the constellation Boötis rises quickly and sets slowly, owing to its lying horizontally when rising and vertically when setting, was noted by Aratus, who says-- "The Bearward now, past seen, But more obscured, near the horizon lies; For with the four Signs the Ploughman, as he sinks, The deep receives; and when tired of day At even lingers more than half the night, When with the sinking sun he likewise sets These nights from his late setting bear their name."[397] The cosmical setting of Boötis--that is, when he sets at sunset--is stated by Ovid to occur on March 5 of each year. With reference to the constellation Hercules, Admiral Smyth says-- "The kneeling posture has given rise to momentous discussion; and whether it represents Lycaon lamenting his daughter's transformation, or Prometheus sentenced, or Ixion ditto, or Thamyrus mourning his broken fiddle, remains still uncertain. But in process of time, this figure became a lion, and Hyginus mentions both the lion's skin and the club; while the right foot's being just over the head of the Dragon, satisfied the mythologists that he was crushing the Lernæan hydra.... Some have considered the emblem as typifying the serpent which infested the vicinity of Cape Tænarus, whence a sub-genus of Ophidians still derives its name. At all events a poet, indignant at the heathen exaltation of Hevelius, has said-- "'To Cerberus, too, a place is given-- His home of old was far from heaven.'"[398] Aratus speaks of Hercules as "the Phantom whose name none can tell."