"It will enable us to generate a force of the ninth magnitude--that much power is necessary to set up what you have so aptly named a zone of force--and will give us a source of fourth, fifth, and probably higher orders of rays which, if they are generated in space at all, are beyond our present reach. The zone of force is necessary to shield certain items of equipment from ether vibrations; as any such vibration inside the controlling fields of force renders observation or control of the higher orders of rays impossible." "Hm ... m, I see--I'm learning something," Seaton replied cordially. "Just as the higher-powered a radio set is, the more perfect must be its shielding?" "Yes. Just as a trace of any gas will destroy the usefulness of your most sensitive vacuum tubes, and just as imperfect shielding will allow interfering waves to enter sensitive electrical apparatus--in that same fashion will even the slightest ether vibration interfere with the operation of the extremely sensitive fields and lenses of force which must be used in controlling forces of the higher orders." "You haven't tested the theory of the fourth order yet, have you?" "No, but that is unnecessary. The theory of the fourth order is not really theory at all--it is mathematical fact. Although we have never been able to generate them, we know exactly the forces you use in your ship of space, and we can tell you of some thousands of others more or less similar and also highly useful forces which you have not yet discovered, but are allowing to go to waste. We know exactly what they are, how to liberate and control them, and how to use them. In fact, in the work which we are to begin today, we shall use but little ordinary power: almost all our work will be done by fourth-order forces, liberated from copper by means of the Rovolon you have given me. But here we are at my laboratory. You already know that the best way to learn is by doing, and we shall begin at once." * * * * * The flier alighted upon a lawn quite similar to the one before the observatory of Orlon, and the scientist led his Earthly guest through the main entrance of the imposing structure of vari-colored marble and gleaming metal and into the vast, glass-lined room that was his laboratory. Great benches lined the walls, and there were hundreds of dials, meters, tubes, transformers and other instruments, whose uses Seaton could not even guess. Rovol first donned a suit of transparent, flexible material, of a deep golden color, instructing Seaton to do the same; explaining that much of the work would be with dangerous frequencies and with high pressures, and that the suits were not only absolute insulators against electricity, heat, and sound, but were also ray-filters proof against any harmful radiations. As each helmet was equipped with radiophones, conversation was not interfered with in the least.