The first of the strangers made a sharp movement which revealed that they had two arms and two legs. The white ship swung around and when its nose was pointed directly at the Tellur it projected a red metal framework to a distance of more than twenty metres.
There was a gentle bump and the two ships were in contact. But there was no blinding flash of atomic disintegration: the two ships that had met consisted of identical matter.
Afra, Yas and Kari heard a low chuckle in their helmet telephones. It was the captain. They exchanged question ing glances.
“I can assure you all, and especially Afra,” Moot Ang said. “Just imagine what we must look like to them. Bulbous dummies with articulated limbs and huge round heads that are three-quarters empty!”
Afra laughed.
“Everything depends on what’s inside the space suits. The outside doesn’t matter.”
“At least they’ve got the same number of legs and arms as we have,” observed Kari.
An accordion-pleated white covering appeared around the metal framework the white ship had projected. Its end reached out toward the Tellur.
The first of the figures on the platform — Moot Ang was certain it was the commander — made inviting gestures that left no doubt as to their meaning, and in response the closed gallery which the crew of the Tellur used to communicate with other ships lying alongside in outer space was ejected from its nest in the lower part of the hull. But the gallery of the Tellur was round, whereas the strangers’ was elliptical in shape. To make it possible to connect the two, the Earth ship’s technicians quickly made a new frame of soft wood, which became stronger than steel as soon as it was exposed to the intense cold of outer space, for the low temperature changed its molecular structure. In the meantime a cube-shaped red-metal box with a black screen in front appeared on the platform of the white ship. Two of the crew members bent over it, then straightened up and backed away. A figure resembling the human body in outline appeared on the screen. Its upper part expanded and contracted while tiny white arrows either flowed into it or were expelled in rhythm with the expansion and contraction.
“Ingenious!” cried Afra. “That’s breathing! Now they’re bound to tell us the composition of their atmosphere. But how?”
As if in answer to her question, the figure on the screen was replaced by a black spot in a greyish annular cloud — evidently the nucleus of an atom surrounded by electrons in orbit. Moot Ang’s throat contracted. He wanted to cry out in amazement, but he couldn’t utter a sound. For now there were four figures on the screen — two, one above the other — in the centre with a thick white connecting line in between, and one on each side with black arrows pointing to them.
With fast-beating hearts, Moot Ang and his companions counted the electrons. The bottom figure probably represented the principal element in the unknown world’s oceans; it showed one electron spinning around the nucleus — hydrogen. The uppermost was by the same token the principal element of their atmosphere — nine electrons in orbit around the nucleus meant fluorine!
“Fluorine!” Afra cried out in despair.
“Keep on counting!” snapped Moot Ang. “Top left — six electrons, that means carbon. Right — seven, meaning nitrogen. Couldn’t be clearer. Pass on the word to draw up a similar table of our atmosphere and metabolism. It’ll be the same as theirs except for the top centre figure, which will be oxygen with its eight electrons instead of fluorine. What a pity!”
When the table was displayed, the astronauts on the observation platform of the Tellur saw the foremost of the white figures on the other space ship start and raise his hand to his helmet in a gesture that made it clear he was no less, if not more, disappointed than the Earthmen.
Bending over the railing of the platform, the captain of the ship from the unknown planet made a sharp movement with his arm as if severing some invisible bond. The spines on his helmet seemed to bristle menacingly at the Tellur, which was then several metres below the level of his ship. Then he raised his arms and brought them down as if trying to indicate two parallel planes.
Moot Ang repeated the gesture, whereupon the other raised one arm high in wordless greeting, turned round and disappeared into the black maw behind him. His companions followed him.
“Let us go down too,” Moot Ang said, pressing the descent lever.
The hatch closed over them before Afra had had more than a fleeting glimpse of the magnificent sight of the stars blazing in all their brilliance in the black void — a sight that never failed to delight her. The lights went on in the airlock and there was a faint hissing of the pumps — the first indication that the air pressure had reached that at the Earth’s surface.
“Shall we set up a dividing wall before joining the galleries?” Yas Tin asked as soo nas he had got his helmet off.
“Yes,” Moot Ang replied. “That’s what the captain of the other ship was trying to tell us. It’s a tragedy that they can’t exist without fluorine, which happens to be deadly to us. Oxygen would be just as lethal for them. Besides, many of our materials, paints and metals which are durable enough in an oxygen atmosphere would corrode from their breathing. Instead of water they have hydrofluoric acid which eats away into glass and attacks all silicates. We will have to put up a transparent partition that is not affected by oxygen while they will have to make another of some substance resistant to fluorine. But we must hurry. We can talk things over while the partition is being made.”
The quenching chamber which separated the crew’s quarters from the engine room of the Tellur was turned into a chemical laboratory. Here a heavy plate of crystallike transparent plastic was cast of ready components brought from Earth and left to set.
In the meantime the white space ship showed no signs of life although it was kept under constant observation.
In the library of the Tellur work was in full swing. The members of the expedition were busy selecting stereofilms and magnetic recordings of photographs of the Earth and its finest works of art. Diagrams and drawings illustrating mathematical functions and the crystal structure of the most common substances on Earth, other planets of our solar system and the Sun were being hurriedly prepared. A large stereoscopic screen was being adjusted and an overtone sound unit which reproduced the sound of the human voice without the slightest distortion was being encased in a fluorine-proof jacket.
During the brief intervals for food and rest, the crew of the Tellur discussed the unusual atmosphere of the planet from which the others had come.
The processes on the unknown planet set in motion by the energy radiated by its sun which made it possible for life to exist and accumulate energy to offset the dissipation of energy, must follow a general pattern similar to that on Earth. A free active gas — oxygen, fluorine or any other — could accumulate in the atmosphere only as a result of the vital functions of plants. Under all circumstances animal life, human beings included, must use up this gas, combining it with carbon, the basic component of both animals and plants.