This section is from the book "Myths And Folk-Tales Of The Russians, Western Slavs, And Magyars", by Jeremiah Curtin. Also available from Amazon: Myths and Folk-Tales of the Russians, Western Slavs, and the Magyars.
The king's son gave heartfelt thanks for the kindness shown him, then went up on the great unclimb-able mountain that supported the heavens. When he had reached the top he took out the three golden hairs and struck them three times with the old latch-string. Behold, a fiery cloud rushed towards him like a shot arrow, with a fearful rumbling and cracking as if a whole stud of horses were before it. and then stood still above his head. All at once he heard from the fiery cloud a triple neighing, at the sound of which, as of a bell, the earth trembled three times. The magic steed rushed out, and like a flood, like a cloud-burst, plunged down by his side, blowing from its nostrils varied flames, - red, blue, and green. The latch-string became such a saddle that for the fur and diamond buttons, and silver and gold embroidery, the earth could not be seen.
"Hip, hop! here am I, dear master! That there be no delay in thy affair, wilt thou not sit on my back that I may be off with thee? Shall I go like the swiftest whirlwind, or like thought, or as a bird can fly?"
"Go, my dear steed, in such fashion that there may be no fault in thee or me".
"But before we set out on the long road," said the magic steed, "I wish to say this: Since such dense darkness reigns in the islands that a spoon might stand straight in it, we must first go to the bright antechamber of the Sun, and take thence one burning ray".
When the steed had thus ended the speech, he rose in the airy heavens. They journeyed and travelled across forty-nine kingdoms till they came to the portals of the earth, 'where two bearded wolves stood on guard. These wolves stood on the road and demanded toll. The toll was no other than two pounds of flesh from the good steed. Now, if two pounds of flesh were taken from the steed, it would be but half magic, and so would never reach the end of the road. Whatever the king's son did not do, he took his gleaming clasp-knife and cut out two pounds of his own flesh; then he threw it to the bearded wolves, and only on this condition did they let him pass.
The king's son pursued his way till he came to the Sun's bright antechamber, where he tied his steed to a diamond pillar; then he bathed in the fire-bath, and rubbed with fire-towels; looking at himself from head to foot in the shining wall of the antechamber as in a mirror, he combed his hair with a golden comb. Here, 'pon my soul, what came of the affair, or what did not, a subject-spirit in the service of the Sun became enraged in good earnest (for his eyebrows struggled with each other), - no doubt it was at the king's son, - and with a single breath, which the son of the hurricane could not withstand, blew straight ahead, so that the king's son did not feel the ground under his feet for seventy-seven miles. Then he fell into a terribly dark opening, and groped along in this cavern, feeling his way like a blind man. If he made a step, he trod on a serpent; if he felt with his hand, he grasped a warty toad; if he looked around, he saw only red-eyed worms, - creeping, crawling things. He went on and on till he heard the plash of seething water. The beating of iron hammers struck his ear-drum, and so struck as almost to break it. This is the place where thunderbolts are made. He went on till he came to a great iron gate, standing open just then; but a tremendous, cursed, hundred-headed dragon, who let no one pass, kept guard there. What could the king's son take hold of? What could he do with his life? Here, upon my soul! what he did, or what he did not do, he took out a sweet-speaking, magic flute, and blew on it so sadly that his tears rolled down. Such touching notes did he draw from the flute that the great powerful beast - the hundred-headed dragon - became as a lamb, lowered his bloody crest; his bristling scales dropped smoothly, one on the other; he stretched on the ground, and cowered, whining like a dog when he beholds his master after an absence. Seeing this, the king's son grew bold, and going straight to the dragon, stepped upon him, walked on his back, and the terrible wild beast did not mind it; he only licked his foot, wagged his tail, and let the king's son pass over.
After he had gone through the gate the darkness began to part; and no wonder, for a charm-given, lovely maiden, in a purple velvet robe, stepped before him. She was no other than Dawn, the dearest and best-beloved daughter of the Sun. Now, the splendid young prince pleased this flower of the skies. She placed him by her side on her winged steed, and flew across the vault of heaven, and they swept on till they reached the razor bridge. When they touched the bridge, their horse became as if he were not; and they crossed so that the horse's feet were not injured, and the razor's edge was not dented. Having passed the razor bridge they came to the copper forest, where were working at that moment the woodcutters of the Sun, who on iron wagons were taking wood to the kitchen, with a terrible rattling and pounding. Thence they rode to the silver forest, where silver-white birds cheered every wanderer. Two of the birds came and sang the sweetest notes. The silver-trees inclined thrice to the daughter of the Sun. Next they reached the golden forest, where sweet-voiced, golden-yellow birds enlivened the visitors, and threw down golden nuts here and there from the trees. The golden forest bent thrice to the daughter of the Sun.
In the middle of the golden forest was Dawn's garden; in the garden her copper-roofed mansion. When the Beauty of the Skies came home the pearly flowers shook their bells, and began to sound. On hearing this, the stars swept forth like a swarm, and glittered round about. The maiden nodded but once, and behold! purple clouds swam before her like so many sky-sacks, which serve on the extended firmament as boats. Dawn took her seat, but first she spread her mantle and seated the king's son at her side. Lest his part of the boat might be heavier, she drew him nearer to her with an embrace; but he dared not embrace in return.