"You know as much as I do, of course, but I'm sure they must break up matter for its energy. As for the condensation problem, I think I have a possible solution of that too--it's the key to the problem of release. There's a lot we don't know now--but we'll have a bigger store of knowledge before this war is over--if we have anything at all!" he added grimly. "It's possible that man may lose knowledge, life, his planets and sun--but there's still plenty of hope. We're not finished yet." "How do you think they got their energy loose?" asked Wade. "Do you think those big blocks of what appeared to be silver were involved in the energy release?" "Yes, I do. Those blocks were probably designed to carry away the power once it was released. How the release was accomplished, though, I don't know. They couldn't use material apparatus to start their release of material energy; the material of the apparatus might 'catch fire' too. They had to have the disintegrating matter held apart from all other matter. This was quite impossible, if you are going to get the energy away by any method other than by the use of fields of force. I don't think that is the method. My guess is that a terrific current of electricity would accomplish it if anything would. "How then are we going to get the current to it? The wires will be subject to the same currents. Whatever they do to the matter involved, the currents will do to the apparatus--except in one case. If that apparatus is made of _some other kind of matter_, then it wouldn't be affected. The solution is obvious. Use some of the light-matter. What will destroy light-matter, won't destroy electricity-matter, and what will destroy electricity-matter, won't disturb light-matter. "Do you remember the platform of light-metal, clear as crystal? It must have been an insulating platform. What we started as our assumptions in the case of the light-metal, we can now carry further. We said that electricity-metals carried electricity, so light-metals would carry or conduct light. Now we know that there is no substance which is transparent to light, that will carry electricity by metallic conduction. I mean, of course, that there is no substance transparent to light, and at the same time capable of carrying electricity by electronic transmission. True, we have things like NaCl solutions in ordinary H_{2}O which will carry electricity, but here it's ionic conduction. Even glass will carry electricity very well when hot; when red hot, glass will carry enough electricity to melt it very quickly. But again, glass is not a solid, but a viscous liquid, and it is again carried by ionic conduction. Iron, copper, sodium, silver, lead--all metals carry the current by means of electron drift through the solid material. In such cases we can see that no transparent substance conducts electricity.