It was an electrolytic process, of course. Ordinarily, when-say- ammonium chloride is broken down by an electric current, ammonium is deposited at the cathode and instantly becomes a gas which dissolves in the water or bubbles up to the surface. With a mercury cathode, it is dissolved and becomes a metallic amalgam, which also breaks down into gas with much bubbling of the mercury. But Denham had worked out a way of delaying the breaking-down, which left him with a curiously white, spongy mass of metal which could be carefully melted down and cast, but not under any circumstances violently struck or strained.
Von Holtz was working at that. On the second day he delivered, snarling, a small ingot of the white metal. He was imprisoned in the lean-to shed in which the electrolysis went on. But Tommy had more than a suspicion that he was in communication with Jacaro.
«Of course,» he said dryly to Smithers, who had expressed his doubts, «Jacaro had somebody sneak up and talk to him through the walls, or maybe through a bored hole. While there’s a hope of finding out what he wants to know through Von Holtz, Jacaro won’t try anything. Not anything rough, anyhow. We mustn’t be bumped off while what we are doing is in our heads alone. We’re safe enough-for a while.»
Smithers grumbled.
«We need that ammonium,» said Tommy, «and I don’t know how to make it. I bluffed that I could, and in time I might, but it would need time and meanwhile Denham needs us. Dalzell is going to send a plane over today, with word of when we can expect our own globe. We’ll try to have the big catapult ready when it comes. And the plane will drop some extra supplies. I’ve ordered a submachine gun. Handy when we get over there in the tree-fern forests. Right now, though, we need to be watching…»
Because they were taking turns looking through the dimensoscope. For signs of Denham and Evelyn. And Tommy was finding himself thinking wholly unscientific thoughts about Evelyn, since a pretty girl in difficulties is, of all possible things, the one most likely to make a man romantic.
In the four days of their hardest working, he saw her three times. The globe was wrecked and ruined. Its glass was broken out and its interior ripped apart. It had been pillaged so exhaustively that there was no hope that whatever device had been included in its design, for its return, remained even repairably intact. That device had not worked, to be sure, but Tommy puzzled sometimes over the fact that he had seen no mechanical device of any sort in the plunder that had been brought out to be demolished. But he did not think of those things when he saw Evelyn.
The Ragged Men’s encampment was gone, but she and her father lingered furtively, still near the pillaged globe. The first day Tommy saw her, she was still blooming and alert. The second day she was paler. Her clothing was ripped and torn, as if by thorns. Denham had a great raw wound upon his forehead, and his coat was gone and half his shirt was in ribbons. Before Tommy’s eyes they killed a nameless small animal with the truncheon-like weapon Evelyn carried. And Denham carted it triumphantly off into the shelter of the tree-fern forest. But to Tommy that shelter began to appear extremely dubious.
That same afternoon some of the Ragged Men came suspiciously to the globe and inspected it, and then vented a gibbering rage upon it with blows and curses. They seemed half-mad, these men. But then, all the Ragged Men seemed a shade less than sane. Their hatred for the Golden City seemed the dominant emotion of their existence.
And when they had gone, Tommy saw Denham peering cautiously from behind a screening mass of fern. And Denham looked sick at heart. His eyes lifted suddenly to the heavens, and he stared off into the distance again, and then he regarded the heavens again with an expression that was at once of the utmost wistfulness and the uttermost of despair.
Tommy swung the dimensoscope about and searched the skies of that other world. He saw the flying machine, and it was a swallow-winged device that moved swiftly, and now soared and swooped in abrupt short circles almost overhead. Tommy could see its pilot, leaning out to gaze downward. He was no more than a hundred feet up, almost at the height of the tree-fern tops. And the pilot was moving too swiftly for Tommy to be able to focus accurately upon his face, but he could see him as a man, an indubitable man in no fashion distinguishable from the other men of this earth. He was scrutinizing the globe as well as he could without alighting.
He soared upward, suddenly, and his plane dwindled as it went toward the Golden City.
And then, inevitably, Tommy searched for the four Ragged Men who had inspected the globe a little while since. He saw them, capering horribly behind a screening of verdure. They did not shake their clenched fists at the flying machine. Instead, they seemed filled with a ghastly mirth. And suddenly they began to run frantically for the far distance, as if bearing news of infinite importance.
And when he looked back at Denham, it seemed to Tommy that he wrung his hands before he disappeared.
But that was the second day of the work upon our own world, and just before sunset there was a droning in the earthly sky above the laboratory, and Tommy ran out, and somebody shot at him from a patch of woodland a quarter of a mile away from the brick building. Isolated as Denham’s place was, the shot would go unnoticed. The bullet passed within a few feet of Tommy, but he paid no attention. It was one of Jacaro’s watchers, no doubt, but Jacaro did not want Tommy killed. So Tommy waited until the plane swooped low- almost to the level of the laboratory roof-and a thickly padded package thudded to the ground. He picked it up and darted back into the laboratory as other bullets came from the patch of woodland.
«Funny,» he said dryly to Smithers, inside the laboratory again; «they don’t dare kill me-yet-and Von Holtz doesn’t dare leave or refuse to do what I tell him to do; and yet they expect to lick us.»
Smithers growled. Tommy was unpacking the wrapped package. A grim, blued-steel thing came out of much padding. Boxes tumbled after it.
«Submachine gun,» said Tommy, «and ammunition. Jacaro and his little pals will try to get in here when they think we’ve got the big solenoid ready for use. They’ll try to get it before we can use it. This will attend to them.»
«An’ get us in jail,» said Smithers calmly, «for forty-’leven years.»
«No,» said Tommy, and grinned. «We’ll be in the fifth dimension. Our job is to fling through the catapult all the stuff we’ll need to make another catapult to fling us back again.»
«It can’t be done,» said Smithers flatly.
«Maybe not,» agreed Tommy, «especially since we ruin all our springs and one gimbal ring every time we use the thing. But I’ve got an idea. I’ll want five coils with hollow iron cores, and the whole works shaped like this, with two holes bored so…
He sketched. He had been working on the idea for several days, and the sketch was ready in his mind to be transferred to paper.
«What you goin’ to do?»
«Something crazy,» said Tommy. «A mirror isn’t the only thing that changes angles to right ones.»
«You’re the doctor,» said the imperturbable Smithers.
He set to work. He puzzled Tommy sometimes, Smithers did. So far he hadn’t asked how much his pay was going to be. He’d worked unintermittently. He had displayed a colossal, a tremendous calmness. But no man could work as hard as Smithers did without some powerful driving-force. It was on the fourth day that Tommy learned what it was.
The five coils had been made, and Tommy was assembling them with an extraordinary painstaking care behind a screen, to hide what he was doing. He’d discovered a peep-hole bored through the brick wall from the lean-to where Von Holtz worked. He was no longer locked in there. Tommy abandoned the pretense of imprisonment after finding an automatic pistol and a duplicate key to the lock in Von Holtz’s possession. He’d had neither when he was theoretically locked up, and Tommy laughed.