"Our outposts are dead in this space," he observed meditatively. The use of the word "outposts" dated him many years back as a soldier, back to the old days of open warfare, which had only now come about again. "Penetration of two miles--" "Tank, sir," said the man of the steady fingers, putting a black pin in position within that area, "let a man out in a gas-mask to examine a pill-box. The tank does not report or reply, sir." "Gas," said the general, noting the spot. "Their new gas, of course. It must go through masks or sag-paste, or both." He looked up to one of a row of officers seated opposite him, each man with headphones strapped to his ears and a transmitter before his lips, and each man with a map-pad on his knees, on which from time to time he made notations and shifted pins absorbedly. "Captain Harvey," said the general, "you are sure that dead spot has not been bombarded with gas-shells?" "Yes, General. There has been no artillery fire heavy enough to put more than a fraction of those posts out of action, and all that fire, sir, has been accounted for elsewhere." The officer looked up, saw the general's eyes shift, and bent to his map again, on which he was marking areas from which spotting aircraft reported flashes as of heavy guns beneath the mist. "Their aircraft have not been dropping bombs, positively?" A second officer glanced up from his own map. "Our planes cover all that space, sir, and have for some time." "They either have a noiseless tank," observed the general meditatively, "or...." The steady fingers placed a red pin at a certain spot. "One observation-post, sir, has reopened communication. Two infantrymen, separated from their command, came upon it and found the machine-gun crew dead, with gas-masks adjusted. No tanks or tracks. They are identified, sir, and are now looking for tank tracks or shells." The general nodded emotionlessly. "Let me know immediately." * * * * * He fell back to the ceaseless study of the board with its crawling sparks and sudden flashes of light. Over at the left, there were four white sparks crawling toward a spot where a blue flash had showed a little while since. A red light glowed suddenly where one of the white sparks crawled. One of the two officers behind the general spoke crisply. Instantly, it seemed, the other three white sparks changed their direction of movement. They swung toward the red flash--the point where a wireless from the tank represented by the first white flash had reported, contact with the enemy. "Enemy tank destroyed here, sir," said the voice above the steady fingers. "Wiped out three of our observation posts," murmured the general, "His side knows it. That's an opportunity. Have those posts reoccupied." "Orders given, sir," said a staff officer from behind. "No reports as yet."