the Earth and all the planets are only as atom. But the fourth dimension!"
La Rue picked up a minute speck of dust from the table and regarded it a moment in silence, then, he went on: "Who knows but that this tiny particle of matter which I hold may contain a universe in that infra-world, and that during our conversation eons may have passed to the possible inhabitants of the planets therein? So we come to the fact that time is the fourth dimension. Let me read you what a scientist of an earlier day has written, a man who was so for ahead of his time that he was wholly unappreciated:
"'If you lived on a planet infinitesimally small, or infinitely big, you would not know the difference. Time and space are, after all, purely relative. If at midnight tonight, all things, including ourselves and our measuring instruments, were reduced in size one thousand times, we should be left quite unaware of any such change.'
"But I wish to read you a message which I received at my radio station on the Eiffel Tower at Paris."
La Rue produced a paper from a pocket and read the following radiogram from Mars:
"'A most horrible catastrophe is befalling us. We are leaving the solar system! The sun grows daily smaller. Soon we shall be plunged in eternal gloom. The cold is becoming unbearable'!"
When the Frenchman had finished reading he continued addressing the physicist: "A few astronomers are aware of the departure of Mars from the system, but are keeping it from the public temporarily. What do you think of this whole business, Shipley?"
"The phenomenon is quite clear,” the latter replied. "Some intelligent beings in this vaster cosmos or supra-universe, in which we are but a molecule, have began an experiment which is a common one in chemistry, an experiment in which one or two electrons in each atom are torn away, resulting, as you already know, in the formation of a new element. Their experiment will cause a rearrangement in our universe."
"Yes," smiled La Rue significantly, "every time we perform a similar experiment, millions of planets leave their suns in that next smaller cosmos or infra-world. But why isn't it commoner even around us?"
"There is where the time element comes in," answered his friend. "Think of the rarity of such an experiment upon a particular molecule or group of molecules, and you will plainly see why it has never happened in all the eons of time that our universe has passed through."
There was a moment's silence as both men realized their human inability to grasp even a vague conception of the idea of relativity. This silence was broken by the foreigner, who spoke in eager accents: "Will you not, my friend, return with me to Paris? And together at my radio station, we will listen to the messages from the truant Mars."
2
The radio station of La Rue was the most interesting place Shipley had ever visited. Here were perfected instruments of television. An observer from this tower could both see and hear any place on the globe. As yet, seeing beyond our Earth had not been scientifically perfected.
La Rue had been eager to hear from his assistant any further messages from Mars. These could have been forwarded to him when he was in the States, but he preferred to wait until his return to his beloved station. There was nothing startlingly new in any of the communications. All showed despair regarding the Martians' ability to survive, with
