"I believe this will be large enough. Besides, I have an idea that the X has other and even more remarkable powers. I don't want to use it all up in this device." [Illustration: "We Can Make a Larger Disk!"] A gang of men had been employed to clear a trail up the side of the mountain in the Adirondacks and construct a road to the summit as none ever had been made to the spot Tom intended to use. A specially large motor truck was built to carry first the telescope, then the giant green disk. It may well be supposed that all these preparations ran into money. Many a groan did Ned give when he studied the mounting cost sheets. Tom, however, was deaf to all his chum's protestations. [Illustration: A Special Truck Was Built] "I had hoped your new bendable glass would more than repay the cost of your telescope," grumbled Ned. "That's gone, and it looks to me as though everything else'll go too. The Swift Construction Company will soon be bankrupt, Tom Swift, if you don't slow down!" "What do you mean, my flexible glass is gone? Why, I've had an application on file in the Patent Office for several months." "Well, for Pete's sake, why didn't you tell me? Here I've been worrying my head off for nothing!" [Illustration: "You'll Be Bankrupt!" Warned Ned] "Sorry, old man. But you know I've had a lot on my mind. However, we must get back the papers, for the thief can make things pretty uncomfortable if he chooses to." As Tom had found out, X would be useful only in an absolutely pure state. To refine it to the proper degree was a painfully slow process, taking in this case a full six weeks. While his chemists labored away under the young inventor's supervision, everything else had been made ready. At last the new element was prepared. The tons of yellow powder were dumped into the heated furnace. [Illustration: His Chemists Worked Away] Three days later the stuff had cooled sufficiently for an inspection to be made. A traveling crane slowly hoisted the massive iron lid of the electric furnace. Tom climbed a ladder and peered down. "It's perfect!" he shouted a moment later. Mr. Damon and Barton Swift were standing anxiously with Ned and the workmen to hear the verdict. At the young inventor's words the group gave a cheer. [Illustration: Tom Peered Down at the Disk] "Bless my stars and planets!" cried Mr. Damon, capering about like a boy. "I can hardly wait till you have your big glass set up!" "It won't be long now," promised Tom, much pleased himself. While the giant disk was being given a final electrical treatment, the youthful inventor was called to the police station. The fugitive crook, Hammer, had finally been nabbed, still with the formula for the bendable glass in his possession. Tom was glad to get this back, even though patent proceedings were under way, for anyone holding the papers could have instituted a costly legal contest. [Illustration: Hammer Had Been Nabbed]