"The batteries are nothing extraordinary, except in strength," he told Jack, "and as near as I can make out the instrument is like any other. It must be some modification in the sending apparatus, some system of 'tuning', perhaps--it's only a surmise. We'll just disconnect the batteries," he concluded, "before we go to monkeying." He proceeded carefully and methodically to carry out his expressed intention. When he had finished the task he heaved a deep sigh of relief. "I'm glad you feel that way, too," said Jack. "I didn't know what might not happen." "Me, either," confessed Darrow. "But now I think we're safe." He proceeded on a methodical search through the intricacies of the apparatus. For a time Jack followed him about, but after a while wearied of so profitless an occupation, and so took to smoking on the window-ledge. Darrow extended his investigations to the bookcase, and to a drawer in the deal table. For over two hours he sorted notes, compared, and ruminated, his brows knit in concentration. Jack did not try to interrupt him. At the end of the time indicated, the scientist looked up and made some trivial remark. "Got it?" asked Jack. "Yes," replied Darrow soberly. He reflected for several minutes longer; then moved to the window and looked out over the city. Absolutely motionless there he stood while the night fell, oblivious alike to the roar and crash of the increasing panic and to the silent figures in the darkened room behind him. At last he gave a sigh, walked quietly to the electric light, and turned it on. "It's the biggest thing--and the simplest--the world has ever known in physics, Jack" said he, "but it's got to go." "What?" asked Jack, rousing from the mood of waiting into which he had loyally forced himself in spite of the turmoil outside. "The man has perfected a combined system of special tuning and definite electrical energy," said Darrow, "by which through an ordinary wireless sender he can send forth into the ether what might be called deadening or nullifying waves. You are no doubt familiar with the common experiment by which two sounds will produce a silence. This is just like that. By means of this, within the radius of his sending instrument and for a period of time up to the capacity of his batteries, a man can absolutely stop vibration of either heat, sound, light, or electricity length. It is entirely a question of simple formulas. Here they are." He held out four closely written pages bound together with manuscript fasteners. "No man has ever before attained this knowledge or this power," went on Darrow, after a moment; "and probably never again in the history of the race will exactly this combination of luck and special talent occur. These four pages are unique."