"What can't we do? We have the Omnimobile. We have machines and tools. We have knowledge, and our hands. We can go anywhere, and do anything! But the first thing is to study, to find out what we have to deal with, and how to fight it." "I suppose so." "Mel, we must go back to that hill." "No! no! Not there! It was only a miracle--and Xenora--that saved us before!" "I've some theories. We'll be better prepared next time." A sudden thought struck me. "Say, couldn't we pay a flying visit to our own world again, and tell what we've found? Then the world would still have a chance, when we are--gone. A half-million Americans, with tanks and heavy artillery, would look mighty good down here. And it would just take a day or two to go." "No," Sam said. "The world would hardly believe it all, even if we carried out what evidence we could. And nothing could be done in time. Then, I'm not sure we could get out. In fact, I'm pretty sure we couldn't. The rockets might carry us three miles high, all right; but we could never break through that water from beneath. We would fall back. Mel, it's up to us!" During the days that followed, Sam spent most of his hours in the little laboratory. He spent much time on those great machines that controlled his forces in the ether. And he invented and developed another device that was more nearly within my understanding. "You know, Mel," he said one day, "I think I can rig up something to protect us from that--fear--that came so near getting us. Ever since you made your telepathic contact with the Green Girl, I have had the idea that the brain sets up disturbances in the ether. We know that the action of the nervous system is electrical in nature, and all electric discharges set up ether waves. It happened that you and she had great minds, created in perfect synchronism, so that each was sensitive to the vibrations of the other. Hypnotism is best explained by such electric theories. "Now, I am convinced that the 'Lord of Flame' is a brain--whether in a human body or not I cannot attempt to say. It creates such powerful etheric disturbances that it was able to affect us at a distance. If that is the case, it ought to be a fairly simple matter to provide insulation against its vibrations. You know that induction or electric action cannot penetrate a conducting cage. I ought to be able to fix a conducting helmet that will prevent the induction of neuronic currents in our brains." A short time after he showed me three helmets, as he called them. They were little more than bags of wire gauze to be put over our heads. He demonstrated that an electroscope draped with one of them remained entirely unaffected by charges brought near it; but it seemed a ridiculously inadequate protection against that terror.