They arose next day to find the Sun shining as brightly as before. Donning their space suits and releasing the pressure in their abandoned landing boat, Billingsley, Gudunek and Woolf stamped their way through the powdery snow to the Panther, Holt’s caterpillar, which was to head the column moving northwards. The driver was Sergeant Regand, a tough farmer from North Dakota, Brooks, Oberth’s radio man, would attend to communications. Holt himself would man the forward gun if things got tough, while Brooks would take the after one.
The Jaguar, under Glen Hubbard, was manned by Clark Winslow and four soldiers, while Leopard was to bring up the rear under Lieutenant Hampstead and the remaining five men of his guard.
After each caterpillar had picked up its trailer, Holt sent Winslow back to assure himself that the abandoned landing boat was as well moored as circumstances permitted, lest she capsize in some storm or blow away across the limitless wilderness of snow. The thought of burning the boat as Cortez had done with his ships ran through Holt’s head. Both the lack of propellants in her tanks and her station near the pole effectively prohibited any return to the orbit where their friends still circled Mars. But finally Holt’s natural conservatism prevailed upon him to preserve what few material possessions he had brought to this distant goal.
As the caterpillars rattled and snorted northward with their trailers, Holt stood in the gun turret of the Panther and surveyed the vast snow field ahead. In the pressurized interior, he had removed his helmet and laid it upon the breech of the gun. Like the others, he still wore his pressure suit. As the mileages were called up to him from below, he entered each odometer reading on the chart where he kept track of their progress along the 190th meridian to which the gyrocompass held their course. If he had estimated correctly, some 25 miles should bring them to the mysterious, concrete Quonset hut which had so attracted his attention during the landing approach.
Tom Knight, whirling around Mars high overhead, had been kept closely in touch by radio with all that occurred. He had returned a description of the joy of the Mars-circlers at the successful landing on the 82nd parallel of latitude, and was fully aware of their course towards the mysterious building Holt had described. Shortly before, he reported that he was able to make out the three dark spots of the caterpillars on the blind snow through Bergmann’s great telescope, and that he had located the mysterious gray building during the half hour that his vessels were able to view the region where the landing party was making its slow progress.
The northward trek had continued for two hours at 12 mph when Holt saw the previously clear horizon become misty and blurred. This he took to be the effect of the melting zone and the haze which would naturally form above it. He turned to look astern. The tracks left by their caterpillars, which had theretofore been almost indistinguishable in the mixture of hoar frost and powder snow, were now clear and distinct, indicating that the snow must be growing stiff and sticky. Sure enough, the thermometer outside his glass dome showed 30° Fahrenheit: just under freezing.
As he meditated upon the rapid increase in temperature, a rounded silhouette rose out of the haze ahead. It could only be the mysterious building!
Quickly he called Jaguar and Leopard with orders to man the guns, again bracketing his binoculars on the projection above the monotonous expanse of snow. There was no movement, no sign of life. But with surprise, he beheld at each end of the strange structure two small turrets protruding from its smoothly rounded roof. Had there been smoke, he would have taken them for chimneys. The heavy machines clattered towards the mystery and stopped 200 yards away at Holt’s radioed command.
The lenses of his glasses revealed nothing. There was no path nor road leading to the building. Around it, crevices in the now melting snow showed green vegetation, apparently thick and mossy. There were no windows nor other apertures in the great, gray block 300 by 100 yards square. The rounded roof met the ground hemispherically at either end. Nor did the two turrets help to uncover the mystery. Their twelve feet of height and nine or ten of diameter were topped off by hemispherical, smooth caps. They could not be chimneys.
No snow was on the rounded roof, but the light northerly wind bringing the haze towards them might have blown it away. That was quite possible… Could there be heat inside?
Staring through the glasses, Holt’s eyes burned with curiosity and concern. Now they seemed to tell him that the upper portion was more lightly shaded than the gray of the lower. Sure enough, he detected a marked line of separation running horizontally around the roof at mid-height. Where the building ended hemispherically, the line ran upward and across the rotund gable. The central portion of the roof was unmistakably of a different material and seemed to have been let into the main structure.
Holt ordered the caterpillars to disperse, one at each end of the weird building, while he with the Panther took position fifty yards from the long, curved southern wall. Useless as they seemed, the tiny gun barrels swung around toward the giant mass.