"Velocity is really 'units of travel through space per unit of travel through time.' Now if we make the time unit twice as great, and the units traveled through space are not changed, the velocity is twice as great. That is, if we are moving five light years per second, make the second twice as long and we are moving ten light years per double-second. Make it ten thousand times as long, and we are traveling fifty thousand light years per ten-thousand-seconds. This is the principle—but there is a drawback. We might increase the velocity by slowing time passage, that is, if it takes me a year for one heartbeat, two years to raise my arm thus, and six months to turn, my head, if all my body processes are slowed down in this way, I will be able to live a tremendous length of time, and though it takes me two hundred years to go from one star to another, so low is my time rate that the two hundred years will seem but a few minutes. I can then make a trip to a distant star—one five light years distant, let us say, in three minutes to me. I then will say, looking at my chronometer (which has been similarly slowed) 'I have gone five light years in three minutes, or five thirds light years per minute. I have exceeded the speed of light.'
"But people back on Earth would say, he has taken two hundred years to go five light years, therefore he has gone at a speed one fortieth of that of light, which would be true—for their time rate.
"But suppose I can also speed up time. That is, I can live a year in a minute or two. Then everyone else will be exceedingly slow. The ideal thing would be to combine these two effects, arranging that space about your ship will have a very rapid time rate, ten thousand times that of normal space. Then the speed of radiation through that space will be 1,860,000,000 miles per second, and a speed of 1,000,000,000 miles per second would be possible, but still you, too, will be affected, so that though the people back home will say you are going far faster than light, you will say 'No, I am going only 100,000 miles per second.'
"But now imagine that your ship and surrounding space for one mile is at a time rate 10,000 times normal, and you, in a space of one hundred feet within your ship, are affected by a time rate 1/10,000 that, or normal, due to a second, reversing field. The two fields will not fight, or be mutually antagonistic; they will merely compound their effects. Result: you will agree that you are exceeding the speed of light!
"Do you understand? That is the principle on which your ship operated. There were two time-fields, overlapping time-fields. Remember the terrible speed with which your ship landed, and yet there was no appreciable jar according to the men? The answer of course was, that their time rate had been speeded enough, due to the fact that one field had been completely shut off, the other had not.
"That is the principle. The system is so complex, naturally, that we have not yet learned the actual method of working the process. We must do a great deal of mathematical and physical research.
"Wish we had it done—we could use it now," mused the terrestrian.
"We have some other weapons, none as important, of course, as the molecular ray and the heat ray. Or none that have been. But, if the enemy have ray shields, then perhaps these others also will be important. There are molecular motion guns, metal tubes, with molecular director apparatus at one end. A metal shell is pulling the power turned on, and the shell leaps out at a speed of about ten miles per second—since it has been super-heated—and is very accurately aimed, as there is no terrific shock of recoil to be taken up by the gun.
"But a more effective weapon, if these men are as I expect them to be, will be a peculiarly effective magnetic field concentrator device, which will project a magnetic field as a beam for a mile or more. How useful it will be—I don't know. We don't know what the enemy will turn against us!"