"Hold it--I'm sinking!" Nadia exclaimed. "I don't integrate at all unless it is absolutely necessary. As long as you stick to general science, I'm right on your heels, but please lay off of integrations and all that--most especially stay away from those terrible electrical integrations. I always did think that they were the most poisonous kind known. I want only a general idea--that's all that I can understand, anyway." "Sure, I forgot--guess I was getting in deeper than is necessary, especially since this whole thing of beam transmission is pretty crude yet and is bound to change a lot before long. There is so much loss that when we get more than a few hundred million kilometers away from a power-plant we lose reception entirely. But to get going again, the receptors receive the beam and from them the power is sent to the accumulators, where it is stored. These accumulators are an outgrowth of the storage battery. The theory of the accumulator is...." "Lay off the theory, please!" the listener interrupted. "I understand perfectly without it. Energy is stored in the accumulators--you put it in and take it out. That's all that is necessary." * * * * * "I'd like to give you some of the theory--but, after all, it wouldn't add much to your understanding of the working of things, and it might mix you up, as some of it is pretty deep stuff. Then, too, it would take a lot of time, and the rest of your friends would squawk if I kept you here indefinitely. From the accumulators, then, the power is fed to the converters, each of which is backed by a projector. The converters simply change the aspect of the rays, from the energy aspect to the material aspect. As soon as this is done, the highly-charged particles--or whatever they are--thus formed are repelled by the terrific stationary force maintained in the projector backing the converter. Each particle departs with a velocity supposed to be that of light, and the recoil upon the projector drives the vessel, or car, or whatever it is attached to. Still with me?" "Struggling a little, but my nose is still above the surface. These particles, being so infinitesimally small that they cannot even be detected, go right through any substance without any effect--they are not even harmful." "Exactly. Now we are in position to go ahead with the lights, detectors, and so on. The energy aspect of the rays you can best understand as simply a vibration in the ether--an extremely high frequency one. While not rigidly scientific, that is close enough for you and me. Nobody knows what the stuff really is, and it cannot be explained or demonstrated by any model or concept in three-dimensional space. Its physical-mathematical interpretation, the only way in which it can be grasped at all, requires sixteen coordinates in four dimensions, and I don't suppose you'd care to go into that." "I'll say I wouldn't!" she exclaimed, feelingly.