"Well, sound recording has come a long way from the tinfoil cylinder that scratched out: 'Mary had a little lamb!' And transportation has come along swell from the days of sliding sledges. You may have the nucleus of an idea, Walt. But I meant its operation instead of its efficiency."
"We have an electron gun of super size," explained Walt. "The cathode is a big affair six feet in diameter and capable of emitting a veritable storm of electrons. We accelerate them by means of properly spaced anodes of the proper voltage level, and we focus them into a nice bundle by means of electrostatic lenses—"
"Whoah, Tillie, you're talking like the venerable Buck Rogers himself. Say that in words of one cylinder, please," chuckled Arden.
"Well, any voltage gradient between electrodes of different voltage acts as a prism, sort of. When you have annular electrodes of the proper size, shape, and voltage difference, they act as a lens."
"In other words, the ring-shaped electrodes are electrostatic lenses?"
"Nope. It is the space between them. With light or electrons a convex lens will converge the light no matter which direction the light is coming from."
"Uh-huh. I see in a sort of vague manner. Now, fellows, go on from there. What's necessary to make this dingbat tick?"
"I want to think out loud," said Channing.
"That's nothing unusual," said Arden. "Can't we go into Joe's? You can't think without a tablecloth, either."
"What I'm thinking is this, Walt. You've been trying to squirt electrons like a fireman runs a hose. Walt, how long do you suppose a sixteen-inch rifle would last if the explosives were constantly replaced and the fire burned constantly?"