Takoorch admitted the justice of this with an acquiescent gesture. and silence fell while the ice grew a fraction of an inch nearer.

Beetchermarlf had the next constructive thought.

“These lights must give off some heat, even if we can’t feel it through the suits,” he suddenly exclaimed. “Why shouldn’t they the ice from forming near them and even let us melt our way to the outside?”

“Worth trying,” was Takoorch’s laconic answer.

Together they approached the frosty barrier. Beetchermarlf built a small cairn of stones leaning against the ice, and set the light, adjusted for full brightness, at its top. They both crowded close, their front ends part way up the heap of pebbles, and watched the space between the lamp and the ice.

“Come to think of it,” Takoorch remarked as they waited, “our bodies give off heat, don’t they? Shouldn’t our just being here help melt this stuff?”

“I suppose so.” Beetchermarlf was dubious. “We’d better watch to make sure that it doesn’t freeze at each side and around behind us while we’re waiting here.”

“What will that matter? If it does, it means that we and the light together are enough to fight the freezing, and we should be able to melt our way out.”

“That’s true. Watch, though, so we’ll know if that’s happening.” Takoorch gestured agreement, and they fell silent again.

The older helmsman, however, was not the type to endure in silence indefinitely, and presently he gave utterance to another idea.

“I know our knives didn’t make much impression on the ice, but shouldn’t it help if we did some scraping right here where it’s nearest the light?” He unclipped one of the blades they carried for general use and reached toward the ice.

“Wait a minute!” exclaimed Beetchermarlf. “If you start working there, how are we ever going to know whether the heat is having any effect?”

“If my knife gets us anywhere, who cares whether it’s the heat or the work?” retorted Takoorch. Beetchermarlf found no good answer ready, so he subsided, muttering something about “controlled experiments” while the other Mesklinite went to work with his tiny blade.

As it happened, his interference did not spoil the experiment, though it may have delayed slightly the appearance of observable results. Body heat, lamp heat, and knife all together proved unequal to the job; the ice continued to gain. They had to remove the lamps from the cairn at last, and watch the latter slowly become enveloped in the crystalline wall.

“It won’t be long now,” Takoorch remarked as he swung the lights around them. “Only two of the power units are free, now. Should we charge up the lights again before they go, or isn’t it worth the trouble?”

“We might as well,” answered Beetchermarlf. “It seems a pity that that’s the only use we can get out of all that power — four of those things can push the Kwembly around on level ground, and I once heard a human being say that one could do it if it could get traction. That certainly could chip ice for us if we could find a way to apply it.”

“We can take the power box out easily enough, but what we’d do afterward beats me. The units put out electric current as once choice, but I don’t see how we could shock the ice away. The mechanical torque you can get from them works only on the motor shafts.”

“We’d be more likely to shock ourselves away if we used the current. I don’t know very much about electricity — it was mostly plain mechanics I got in the little time I was at College — but I know enough of it can kill. Think of something else.”

Takoorch endeavored to comply. Like his young companion, he had had only a short period of exposure to alien knowledge; both had volunteered for the Dhrawn project in preference to further classwork. Their knowledge of general physics might have compared fairly well with that of Benj Hoffman when he was ten or twelve years old. Neither was really comfortable in thinking about matters for which no easily visualized model could be furnished.

They were not, however, lacking in the ability to think abstractly. Both had heard of heat as representing the lowest common denominator of energy, even if they didn’t picture it as random particle motion.

It was Beetchermarlf who first thought of another effect of electricity.

“Tak! Remember the explanations we got about not putting too much power into the trucks until the cruiser got moving? The humans said it was possible to snap the treads or damage the motors, if we tried to accelerate too fast.”

“That’s right. Quarter power is the limit below a hundred cables per hour.”

“Well, we have the power controls here where we can get at them, and those motors certainly aren’t going to turn. Why not just turn on the power on this truck and let the motor get as hot as it wants to?”

“What makes you think it will get hot? You don’t know what makes those motors go any more than I do. They didn’t say it would make them hot, just that it was bad for them.”

“I know, but what else could it be. You know that any sort of energy that isn’t used up some other way turns into heat.”

“That doesn’t sound quite right, somehow,” returned the older sailor. “Still, I guess anything is worth trying now. They didn’t say anything about the motor’s wrecking the rest of the ship, too; and if it ruins us — well, we won’t be much worse off.”

Beetchermarlf paused; the thought that he might be endangering the Kwembly hadn’t crossed his mind. The more he thought of it, the less he felt justified in taking the chance. He looked at the relatively tiny power unit nestling between the treads of the nearby truck, and wondered whether such a minute thing could really be a danger to the huge bulk above them. Then he remembered the vastly greater size of the machine which had brought him and his fellows to Dhrawn, and realized that the sort of power which could hurl such immense masses through the sky was not to be handled casually. He would never be afraid to use such engines, since he had been given a chance to become familiar with their normal and proper handling; but deliberately misusing one of them was a different story.

“You’re right,” he admitted somewhat inaccurately — Takoorch had been, after all, willing to take the chance. “We’ll have to work it differently. Look, if the tracks are free to turn, then we can’t damage the motor or the power box; and just stirring up water will warm it.”

“You think so? I remember hearing something like that, but if I can’t break up this ice with my own strength it’s hard to see how simply stirring water is going to do it. Besides, the trucks aren’t free; they’re on the bottom with the Kwembly’s weight on them.”

“Right. You wanted to dig. Start moving rocks; that ice is getting close.”

Beetchermarlf set the example and began prying the rounded cobbles from the edges of the treads. It was a hard job even for Mesklinite muscles. Smooth as they were, the stones were tightly packed; and when one was moved, there was not too much room in which to put it. The two labored furiously to clear a ditch around the truck, and were frightened at the time it took.

When the ditch was deep enough they tried to pry stones from under the treads, and this was even more discouraging.

The Kwembly had a mass of about two hundred tons. On Dhrawn, this meant a weight of sixteen million pounds to distribute among the fifty-six remaining trucks, and the mattress did a good job of distributing. Three hundred thousand pounds, even if it is a rather short three hundred thousand, is rather too much even for a Mesklinite — whose weight at even Mesklin’s pole is little over three hundred. It is a great deal even for some eight square feet of caterpillar tread; if Dhrawn’s gravity had not done an equally impressive job of packing its surface materials, the Kwembly and her sister vehicles would probably have sunk to their mattresses before travelling a yard.