John W. Campell (Jr.) used to have brainstorms: in fact, he invented _two_ of THE BEST WAYS TO GET AROUND. One, in the first of the ARCOT, MOREY, and WADE stories, "PIRACY PREFERRED", was that of molecular motion. All the little molecules in a bar of metal go madly around in every possible direction. If you could invent, as Campbell did in the story, an electro-magnetic vibration that would force all the mollecules to go in the same direction, then the bar of metals would go in that direction, since it would be them. So Mr. Campbell hooked the thing up to his ship, and off he went to Venus, or some other planet. Well, it _would_ work, wouldn't it, _provided_ (ah yes!) you could make all the mollecules go into one directional flow. And the other brainstorm was when Aarn Munro, in the MIGHTIEST MACHINE, decided that momentum and velocity were wave formations, and therefore, one should be able to _tune into them_! (Anyone should be able to think up a simple theory like that.) Not a bad WAY TO GET AROUND--in a science fiction story. Back in 1930, or some such year, Charles R. Tanner wrote THE FLIGHT OF THE MERCURY, in the old WONDER STORIES. In that story he told you just how to go ahead and make an ETHERPROPELLER, provided there is such a thing as ether, and Osmium B. The theory is: you use water screws, air propellers, and so why not an ether propeller? Put a cork in motionless water. Start a wave motion in the water with your hand. If the length of the wave is greater than the diameter of the cork, the cork just bobs up and down and stays where it is. If the lengths of the waves are shorter than the diameter of the cork, the waves go around it, and the cork still stays right where it is. If the length of the wave is exactly the diameter of the cork, tho cork rides right off, in the trough of the wave, at the same speed as that of the wave formation. Now invent an electro-magnetic vibration--by useing the metal Osmium B--exactly the length of a Copper atom. Make your ship of copper, putting the ether propeller, that which causes vibration in the ether, at the end of the ship, and presto! all the copper atoms move along in the trough of the ether waves, at the same speed as the other waves, which is the speed of light. And, Mr. Tanner is off for Mars, in a super-plausibly scientifictional way.