"No," mused Arcot. "That's the funny thing. They don't seem to be bothered by the acceleration. They actually jumped a little off the floor when we started, and didn't seem to experience much difficulty when we stopped." He looked thoughtful for a moment. "You know, when Torlos was bending that crowbar back there in the ship, I picked up a curious thought—I wonder if—" He turned to the giant alien. "Torlos, you once gave me the thought-idea 'bone metal'; what is that?"
Torlos looked at him in surprise and then pointed mutely to a heavy belt he wore—made of closely woven links of iron wire!
"I was right, Morey!" Arcot exclaimed. "These men have iron bones! No wonder he could bend that crowbar! It would be as easy as it would for you or me to snap a human arm bone!"
"But, wait a minute!" Morey objected. "How could iron grow?"
"How can stone grow?" countered Arcot. "That's what your bones are, essentially—calcium phosphate rock! It's just a matter of different body chemistry. Their body fluids are probably alkaline, and iron won't rust in an alkaline solution." Arcot was talking rapidly as they followed the aliens down the long corridor.
"The thing that confirms my theory is that elevator. It's merely an iron cage in a magnetic beam, and it's pulled up with a terrific acceleration. With iron bones, these men would be similarly influenced, and they wouldn't notice the acceleration so much."
Morey grinned. "I'll be willing to bet they don't use cells in their prisons, here! Just magnetize the floor, and the poor guy could never get away!"
Arcot nodded. "Of course, the bones must be pure iron; their bones evidently don't retain any of the magnetism when they leave the field."
"We seem to be here," Morey interrupted. "Let's continue the discussion later."
Their party had stopped just outside a large, elaborately carved door, the first sign of ornamentation the Earthmen had seen. There were four guards armed with pistols, which, they discovered later, were powered by compressed air under terrific pressure. They hurled a small metal slug through a rifled barrel, and were effective over a distance of about a mile, although they could only fire four times without reloading.