The air of the planet seemed thick with traffic, mighty half-million ton lift freighters and passenger ships setting out toward Earth, smaller private machines, but none were slower nor faster than the others, for all were limited only by the acceleration they could stand. There was only one speed limit, that of economical, safe operation, for with all space to move in, there was no need of speed laws. Yet it seemed impossible to make any more than two thousand miles an hour through this slow moving air traffic—then there shone a little emblem on the bow of the little iridescent metal ship, and a huge freighter swerved respectfully aside. As by magic a lane opened through the thick traffic as the sign of the System President shone out.

The little ship darted along the ground a short way, then rose vertically, only to settle lightly on the roof of the great System Capitol. Two men came out and walked quickly to the elevator entrance, where three guards, armed with disintegration ray projectors, greeted them with a stiffly military salute. The larger of the men responded with a smile, and a brief salutation in the common language of the System, for these great men were Martians, each well over eight feet tall. They entered the lift, and quickly sank down one hundred and fifty stories to the Governmental Offices. They proceeded directly to the great Cabinet chamber, down through the long halls, lined on each side by huge murals depicting scenes in the history of the three planets. Then they came to the cabinet room and entered.

Thirty-nine men were seated there now, but as the two entered, they rose, and waited for the President to be seated. The forty greatest living men were in that room that day and all worked together, for they were scientists who had learned the value of cooperation. There was no rivalry, for each was the greatest in his own field and had no aspirations toward any other branch of science. And none but conceded the power of the Presidency gladly to the greatest of them, Steven Waterson of Earth.

"Gentlemen of the Cabinet, I am beginning to believe it is time we had something added to the Constitution forbidding Members of the Cabinet to rise on the entry of the President." Waterson deeply appreciated that compliment, as they all knew, but he could not feel at home in an atmosphere of diffidence. He was a scientist, a planner, not a diplomat. "I am sorry I was forced to make you gentlemen wait for me, but as you see," he continued, pointing to the great map of the System on the ceiling of the Cabinet chamber, where the slow motion of the planets in their orbits was being accurately traced, "Earth is in superior conjunction at present, and I could not make better time.

"I see from this memorandum that has been prepared for me that Mansol Korac, Martian Astro-physicist, is to be our first speaker. I take it you have had no official discussion as yet?"

He was correct in this assumption for the men had convened shortly before at his radio announcement that he would land within an hour.

Some years before there had been some agitation to have the Cabinet meetings carried on by Radio-vision plates, but the low speed of light had made the speeches a terrible failure, as they would frequently have to wait ten or even fifteen minutes while the radio messages were reaching them. Over short distances that method was practicable, but between planets light is too slow, it cannot be used.

"Some time ago our radio engineers developed a new instrument for detecting exceptionally short waves. They really came under the category of the longer heat radiations, but were detected electrically. While experimenting with this device they have been consistently picking up signals apparently originating in free space. At first these signals were exceedingly weak, but their intensity has grown uniformly and rapidly, and from the results some amazing conclusions have been drawn.

"They are originating at some source or sources out in space in the direction of the sun Sirius. I was asked to help the radiation engineers under Horus Mal in the calculation of the Astro-physical aspect of the problem. I believe that there are some man-made vehicles out there in space sending those signals. No man of the System has ever had reason to venture beyond the orbit of Neptune for any great distance; there would be no reason for it, as none of the outer planets are habitable. The rate of increase of the signal strength, coupled with observations made from Earth, Mars and Venus, have made it evident that they are at present about one and a quarter billion miles away, but approaching us at the rate of 1000 miles a second. This means that in approximately two weeks they will reach our planets.