"Can't be done, I guess, Mart," he confessed, ruefully. "You see, it works fine up to a certain point; but beyond that, nothing doing. I've just found out why--and in so doing, I think I've made a contribution to science. At velocities well below that of light, light-waves are shifted a minute amount, you know. At the velocity of light, and up to a velocity not even approached by the Fenachrone vessels on their longest trips, the distortion is still not serious--no matter how fast we want to travel in the _Skylark_, I think I can guarantee that we will still be able to see things. That is to be expected from the generally-accepted idea that the apparent velocity of any ether vibration is independent of the velocity of either source or receiver. However, that relationship fails at velocities far below that of fifth-order rays. At only a very small fraction of that speed the tracers I am following are so badly distorted that they disappear altogether, and I have to distort them backwards. That wouldn't be too bad, but when I get up to about one per cent of the velocity I want to use, I can't calculate a force that will operate to distort them back into recognizable wave-forms. That's another problem for Rovol to chew on, for another hundred years." "That will, of course, slow up the work of clearing the Galaxy of the Fenachrone, but at the same time I see nothing about which to be alarmed," Crane replied. "You are working very much faster than you could have done by waiting for the torpedoes to arrive. The present condition is very satisfactory, I should say," and he waved his hand at the galactic model, in nearly three-fourths of whose volume the green lights had been replaced by pink ones. "Yeah, pretty fair as far as that goes--we'll clean up in ten days or so--but I hate to be licked. Well, I might as well quit sobbing and get busy!" In due time the nine hundred and sixth Fenachrone vessel was checked off on the model, and the two Terrestrials went in search of Drasnik, whom they found in his study, summing up and analyzing a mass of data, facts, and ideas which were being projected in the air around him. "Well, our first job's done," Seaton stated. "What do you know that you feel like passing around?"