On the first day one of Tommy's friends drove in in answer to a telegram. It was Peter Dalzell, with men in uniform apparently festooned about his car. He announced that a placard warning passersby of smallpox within, had been added to the decorative signs upon the gate, and stared incredulously at the interior of the big brick barn. Tommy grinned at him and gave him plans and specifications of a light steel globe in which two men might be transported into the fifth dimension by a suitably operating device. Tommy had sat up all night drawing those plans. He told Dalzell just enough of what he was up against to enlist Dalzell's enthusiastic cooperation without permitting him to doubt Tommy's sanity. Dalzell had known Tommy as an amateur tennis player, but not as a scientist. He marveled, refused to believe his eyes when he looked through the dimensoscope, and agreed that the whole thing had to be kept secret or the rescue expedition would be prevented from starting by the incarceration of both Tommy and Smithers in comfortable insane asylums. He feigned to admire Von Holtz, deathly white and nearly frantic with a corroding rage, and complimented Tommy on his taste for illegality. He even asked Von Holtz if he wanted to leave, and Von Holtz snarled insults at him. Von Holtz was beginning to work at the manufacture of metallic ammonium. * * * * * 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 drily 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.