Entering, they stood before the transparent bulkhead, awaiting the Martian's next move. With some perturbation, they saw him push a button which closed behind them a semi-cylindrical sliding door of metal, confining them within a cylinder whose other half was composed of the curved pane behind which the Martian stood. A hissing sound indicated that the airlock was being filled so that they might pass into a larger pressurized compartment without major discomfort.
The three Earthlings gazed with attentive concern at the Martian's doings at a small switchboard. There was no backing out now; they could not even radio to the waiting Sam Woolf. With apparent unconcern, the Martian continued to pull switches and push buttons.
Holt's exterior pressure meter in his helmet now indicated 4 pounds per square inch; the interior of his suit held 7 psi. A glance at the gas analyzer from his pocket showed 40 % oxygen and 3 % carbon dioxide. The rest was inert gas of some unknown kind.
Should this be nitrogen, which his analyzer could not show, the prospects were good indeed. Even other noble gases such as helium or argon would offer no hindrance to satisfactory respiration. He could, however, by no means be certain that their Martian was flooding them with something safely respirable by terrestrial human lungs.
Holt's space suit inflation collapsed and the pressure gauge now showed 10 psi. This corresponded to an altitude of 25,000 feet altitude on Earth, where 40 % oxygen may be breathed with impunity without fear of intoxication. Breathing masks commonly used by aviators furnished a higher oxygen percentage than the 21 % of the terrestrial atmosphere.
As the pressures equalized, the inner glass door slid back. The Martian's face lit with a friendly smile as he pressed the palm of his right hand over the spot where his heart was — if the inner anatomy of Martians resembled that of terrestrial humans as much as did their exteriors. Holt and his companions followed suit and then stepped towards him in the elevator which he evidently occupied. Silently, the Martian pushed a button, and the lift descended to the floor of the great pump house.
On the way down, Holt removed his helmet and took a deep breath. Aside from a great feeling of relief at the presence of relatively vast quantities of breathable air of adequate oxygen content, he felt no effects. A silent prayer of gratitude that the Martians had created an artificial atmosphere suitable to their brethren from Earth arose within his heart. Few things could so favorably affect the coming effort to reach an understanding with them.
The terrestrial trio, bearing their helmets under their arms, followed the silent Martian down a long corridor lined on both sides with beautifully ornamented metal doors. The corridor glowed with a clear, warm light, although there were no lamps or other apparent sources of illumination. Holt cudgeled his brains for an understanding of this phenomenon. Then he realized that the walls themselves were luminescent, like the symbols on a watch dial, though vastly brighter! Here the ancient dream of illumination engineers had become real — light without heat! No incandescent wire nor flaming arc threw out vast heat losses while producing limited light. Martian engineers had solved the mystery of the firefly and applied the solution to practical illumination problems!
A feeling of infinite satisfaction overwhelmed Holt, for he could see that on the economic side alone, he might return to Earth with an infinite variety of technological and economic advances to be applied to the amelioration of human living conditions. The initial friendliness of their reception gave ground for hope that the Martians would not hesitate to part with their formulae and methods.
The guide stopped by one of the metal doors lining the corridor, opened it, and ushered them into a large, windowless room decorated with carmine red patterns of pleasing outline. Opposite the door sat a venerable, dignified Martian at a long, ebonite table from which he arose at their entrance and laid his hand upon his heart. When they had countered his greeting in like manner, he motioned them to be seated upon a long, cushioned bench across the table from him.
Their Martian guide thereupon intoned a melodious speech in words without significance to any of the visitors. From time to time the dignified, elderly person interrupted smoothly with what could only be questions. Gudunek listened intently to every inflection and syllable, attempting to coordinate the words with the remarkably restrained gestures accompanying them. He could not get even an inkling of the Martians' reactions to the arrival of Earthlings upon their transparent rooftop.
There was a pause in the smooth flow of language and both looked at Holt with expressions of amicable interrogation. Drawing from his briefcase a diagram prepared for the first interview with any authorities they might meet, Holt placed it upon the table before the elderly Martian.
Clearly and unmistakably portrayed was the Solar system with the five inner planets, Mercury, Venus, Earth, Mars and Jupiter. Each orbit was marked with its astronomical signs and the direction of rotation of its planet. The route of the expedition stood out in brilliant red, with an arrow marking the direction of travel. The ancient art of astronomy was surely the most likely ground upon which to base a set of semantic symbols capable of development into broader means of communication between the denizens of separate planets.
The senior of the two Martians bent over the diagram with evident interest and understanding. Holt's finger point to his own group and then to the Earth, followed the flight path; then indicated their hosts and their planets. He then arose and placed his hand upon his heart after the Martian method of greeting. The senior Martian followed suit, turning thereafter with a wry smile to a small cabinet in the wall. He opened the cabinet and adjusted two knobs within. No sooner had he done so than the blood of the visitors suffused their faces with embarrassment, for a voice in colloquial English sounded forth:
"Can you still hear me, Tom" it questioned. "If we don't get out of that building within 24 hours, the caterpillars will proceed northward along the 190th meridian to the equator where they'll start preparing the landing strip."
It was Holt's own voice, evidently intercepted and recorded by the Martian radio system. While it was likely that the significance of the words entirely escaped their hosts, it was at least entirely clear that the latter were anything but ignorant of what was going on in an interplanetary way. It would be well to be careful in dealing with people of that sort…
The Martian shut off the record and smiled tolerantly at Holt and his party whose answering grins held no small portion of embarrassment. Holt felt that matters were progressing rather better than expected, despite the evident lack of privacy of their communications.
The elderly Martian now extracted a large sheet from a drawer in the wall and spread it before Holt. It seemed an organization chart, being covered with circles arranged in pyramidal form and containing mysterious symbols.
The Martian selected one of the small circles in the bottom row and placed his finger upon it. He put a finger of his other hand upon his breast and nodded as much as to say, "This is where I am." Then, with a finger on the larger circle at the top of the pyramid, he gestured into the room and said something which sounded like "Ahla."
"By Jove," spoke Billingsley with a perfectly straight face but with a trace of roguishness in his voice, "Looks rather as though the British Labor Party had gotten here before us! Mars seems almost as bureaucratic as jolly Old England!"
Holt produced his map of the Red Planet, showing the mark he had made to locate the pumping station in which they were being entertained. Then he pointed at the ground below them. Saying "Ahla" in a rising and questioning inflection, he offered the Martian his pencil. Accepting it promptly, the latter poised it above the circular, vegetal area over which they had flown when approaching the landing and made a cross in the center. It was Lacus Solis, and the repetition of the word "Ahla" convinced the visitors that here must be the center of Martian civilization.