"In the projected space-vessel we shall install converters to utilize all the energy, so that there will be no loss whatever. Since such converters must be designed and built especially for each installation, and since they require a high degree of precision, it is not worth while to construct them for a purely temporary mechanism, such as this one." * * * * * The walls of the laboratory were opened, ventilating blowers were built, and refrigerating coils were set up everywhere, even in the tubular structure and behind the visiplates. After assuring themselves that everything combustible had been removed, the two scientists put on under their helmets, goggles whose protecting lenses could be built up to any desired thickness. Rovol then threw a switch, and a hemisphere of flaming golden radiance surrounded the laboratory and extended for miles upon all sides. "I get most of the stuff you've pulled so far, but why such a light?" asked Seaton. "As a warning. This entire area will be filled with dangerous frequencies, and that light is a warning for all uninsulated persons to give our theater of operations a wide berth." "I see. What next?" "All that remains to be done is to take our lens-material and go," replied Rovol, as he took from a cupboard the largest faidon that Seaton had ever seen. "Oh, that's what you're going to use! You know, I've been wondering about that stuff. I took one back with me to the Earth to experiment on. I gave it everything I could think of and couldn't touch it. I couldn't even make it change its temperature. What is it, anyway?" "It is not matter at all, in the ordinary sense of the word. It is almost pure crystallized energy. You have, of course, noticed that it looks transparent, but that it is not. You cannot see into its substance a millionth of a micron--the illusion of transparency being purely a surface phenomenon, and peculiar to this one form of substance. I have told you that the ether is a fourth-order substance--this also is a fourth-order substance, but it is crystalline, whereas the ether is probably fluid and amorphous. You might call this faidon crystallized ether without being far wrong." "But it should weigh tons, and it is hardly heavier than air--or no, wait a minute. Gravitation is also a fourth-order phenomenon, so it might not weigh anything at all--but it would have terrific mass--or would it, not having protons? Crystallized ether would displace fluid ether, so it might--I'll give up! It's too deep for me!" said Seaton.