The nine mothers proceeded to nourish their babe on the strength of the earth, the moisture of the sea, and the heat of the sun, which singular diet proved so strengthening that the new god acquired his full growth in a remarkably short space of time, and hastened to join his father in Asgard. He found the gods proudly contemplating the rainbow bridge Bifröst, which they had just constructed out of fire, air, and water, the three materials which can still plainly be seen in its long arch, where glow the three primary colours: the red representing the fire, the blue the air, and the green the cool depths of the sea.
The Guardian of the Rainbow
This bridge connected heaven and earth, and ended under the shade of the mighty world-tree Yggdrasil, close beside the fountain where Mimir kept guard, and the only drawback to prevent the complete enjoyment of the glorious spectacle, was the fear lest the frost-giants should make their way over it and so gain entrance into Asgard.
The gods had been debating the advisability of appointing a trustworthy guardian, and they hailed the new recruit as one well-fitted to fulfil the onerous duties of the office.
Heimdall gladly undertook the responsibility and henceforth, night and day, he kept vigilant watch over the rainbow highway into Asgard.
“Bifröst i’ th’ east shone forth in brightest green;
On its top, in snow-white sheen,
Heimdal at his post was seen.”
Oehlenschläger (Pigott’s tr.).
To enable their watchman to detect the approach of any enemy from afar, the assembled gods bestowed upon him senses so keen that he is said to have been able to hear the grass grow on the hillside, and the wool on the sheep’s back; to see one hundred miles off as plainly by night as by day; and with all this he required less sleep than a bird.