As the notes of the song arose, the prismatic colors ceased in the dome. The prisms disappeared. Doors glided back in the golden roof, and an immense circular plate, or lens, of crystal made its appearance. So high was the arch of the dome where the crystal lens was hung, that it was impossible from the floor to judge its size; but it must have been at least thirty feet in diameter. It was set in a metal rim, and the whole was swung into place by chains, the mechanism doubtless operated by servants of Rhaen concealed in the vault of the dome.
Tilted slightly to the east, the crystal hung. Above it a round aperture suddenly appeared in the roof. Through that opening shot a splendid shaft of sunshine that pierced the gloom of the temple-hall like an arrow of light. Blinding in its radiance, it cut downward and struck on the basalt altar, full on the head of the bull.
Immediately arose the stench of burning hair and sizzling flesh. The power of the crystal lens so condensed the light-ray that where it fell its heat was all-consuming. Within half a minute naught was left of the head of the sacred bull save a few cinders and bits of calcined bone and charred tips of the horns.
Where the head had been, the basalt rock glowed ruby-red in the path of that awful lance of fire. Inch by inch, and very slowly, the consuming ray crept along the altar toward the head of the girl.
Rose had been nearly blinded, even through her closed lids, by the flash of light from the dome. Although she could not turn her head to see, she could smell the scorching flesh of the bull, and could guess what was coming.
"Good-by, my love, good-by," she said in her heart. Then He to whom she had prayed made answer, and she fainted.
Louder rose the chant of the priests. The merciless finger of their god moved on. Bel-Ar strained forward in his stone seat and stared at the sacrifice as though fascinated.
Some five feet were yet to be traversed by the ray before it would reach the girl, when a soldier ran up the southern steps of the temple and hurled himself through the kneeling ranks of the priests. Behind him a wild clamor of battle arose in the street.
"Adlaz is lost!" shouted the soldier, as he broke into the open space before the king. "Already is the foe at the very gates of Shamar!"
Without stirring in his seat, hardly removing his eyes from the altar, Bel-Ar gave an order to the captains behind him. The silent files of the palace-guard came from behind the pillars and ranged themselves before the four entrances of the temple.