[Figure 73: A DARK NEBULA (S-SHAPED) IN OPHIUCHUS. Photograph by Mount Wilson Observatory through the 100-inch Hooker telescope.] There is also a Cross on the Milky Way with a dark nebula beside it in a conspicuous position in the southern hemisphere, although there the cross is not quite as perfect as our cross in the north, for it is formed of only four bright stars instead of five. Even our cross is not quite perfect, for one star, the "diamond-studded nail" holding it together, is just a little out of line. Julia E. Rogers in "Earth and Sky" has said that her fingers fairly "itch to put it where it belongs." Imagine! And since she has so aptly expressed it, we now all feel that way. This outlined figure of the great Northern Cross forms the basis of a constellation called Cygnus, the Swan. [Figure 74] The bill of the Swan lies on Albireo, the double star at the foot of the Cross, while its wings curve gracefully back from the armpiece. According to the story of Phæthon and Cycnus, Phæthon, after his hectic ride in the sun-chariot, fell a "charred fragment" into the river Eridanus. Jupiter's thunderbolt had hit its mark: "And Phæthon caught in mid-career, And hurled from sun to utter sunlessness, Like a flame-bearded comet, with ghastliest hiss, Fell headlong in the amazed Eridanus." --_Worsley._ Phæthon's three sisters, the Heliades, wept so bitterly on the banks of the Eridanus that the compassionate gods changed them into poplar trees and their tears into amber. Ovid pictures their terrible grief-- "All the night long their mournful watch they keep, And all the day stand round the tomb and weep." Cycnus, Phæthon's friend, also grieved deeply and watched over the waters for many days. While watching thus his neck grew longer and longer until at last it became perfectly atrocious. The gods again looked down in pity, metamorphosed the youth into a swan and placed him on the river of the Milky Way. "For Cycnus loved unhappy Phæthon, And sung his loss in poplar groves alone, Beneath the sister shades to soothe his grief, Heaven heard his song and hastened his relief. And changed to snowy plumes his hoary hair, And winged his flight to sing aloft in air." --_Virgil._