"Others have examined it before me, Xax. I have not heard that their examinations saved them. Besides, if the death that lurks in the tower of Zut still lives, I have no need to fear Guantra."

They were quite close to the doorway now, and looking in they glimpsed something white and shining on the tiled floor. As they drew nearer, the heaps of white stuff grew plainer.

They were bones. Human bones: what was left of the skeletons of many men.

Kortha lifted his head to survey the doorway. His green eyes blazed with challenge, but their fire was controlled, and alert. He saw the entrance plain and severe in style, affording no clue as to the manner of its deadliness. From the way in which the walls shone, so clearly translucent with the hint of inner fires deep within them, he knew that the tower was built of transvaline, that rare building material whose secret was lost with so many others during the Great War.

In the walls two tall, faint strips of black shone dully: the doors of this queer adit.

Kortha swung his hammer in his hand and tossed it through the opening. The doors remained open, and the bolt of force that he half expected to sweep from somewhere at the hammer, remained hidden.

He grunted to Xax, "Come on. No sense wasting time out here, like dogs fretting before a bear's cave."

They passed the threshold together, and stood in a domed chamber, circular in shape, with another doorway beyond and opposite the entrance. There were words on the lintel above its arch.

"Science chamber," whispered Kortha, and started toward it.

Behind them was a metallic whisper, susurrating in the stillness. Kortha whirled and cursed and leaped. The doors closed before his shoulder struck their smooth black surface. He hit and bounced slightly, jarred. Kortha swore slowly, fluently, looking at the doors.