The jealous and vengeful Juno was always on the watch whenever her lord took a fancy to go wandering about the earth; so to woo the gentle Io unseen by his wife required some diplomacy on Jupiter's part. Accordingly he spread a thick cloud over the meadow where he was wont to meet the maiden, and trusted that its appearance would not arouse Juno's suspicions. He also took the precaution to visit Io at the time when the watchful queen of heaven was accustomed to sleep; but one day Juno awoke sooner than usual, and finding Jupiter absent, she at once surmised that he was adventuring again in some love-affair. When she looked down at the earth, she saw the thick cloud that hung over the meadow and noticed that it never altered its position, no matter how the winds blew. Feeling sure that this was some trick intended to deceive her, the wrathful goddess glided down to the earth and appeared at the astonished Jupiter's side--but not before he had had time to change Io into a heifer. "Golden-sandaled" Juno walked about the meadow gathering flowers, then she asked her husband why he was lingering there, so far from bright Olympus. Jupiter answered that he was amusing himself by creating a heifer. This explanation did not deceive Juno; but she pretended to be satisfied, and praised the beautiful creature's glossy skin and large soft eyes. Then she demanded it of Jupiter as a gift, and the ruler of the gods, not knowing how to refuse, consented. The triumphant goddess led away the heifer and put her in charge of Argus. Now Argus had a hundred eyes, and though he often went to sleep, some of his eyes always kept awake; so Juno felt sure that no device of Jupiter's could enable Io to escape from the watchful guardian who never wholly slept. Meanwhile Jupiter was in despair over this unhappy ending to his wooing, and sought the help of Mercury, who often lent his ready wits to gods and mortals in distress. Laying aside his cap and sandals and snake-entwined wand, by which he might easily be recognized, Mercury went down to the earth in the disguise of a shepherd. With his pipes in his hand he strolled through the country until he came to the mountain-side, where Argus sat watching the heifer; and when he began to play, the music was so sweet that Argus begged him to stop awhile that he might listen longer to the wonderful playing. The wily god consented, and as he piped on, some of the hundred eyes grew drowsy with sleep, but some of them stayed open and watchful.