This ship must have caught some slight noise of ours, however, in its sensitive instruments, for we heard its electronic devices go into play, and picked up the routine report of the noise to its Base Ship Commander. But from the nature of the conversation, I judged they had not identified it, and were, in fact, more curious about the detonations they were picking up now from the Bad Blood lands some sixty miles or so to the west. Immediately after this ship had shot by, we took the air again, and following much the same route that I had taken the previous night, climbed in a long semi-circle out over the ocean, swung toward the north and finally the west. We set our course, however, for the Sinsings' land north of Nu-yok, instead of for the city itself. CHAPTER XII The Finger of Doom As we crossed the Hudson River, a few miles north of the city, we dropped several units of the Yellow Intelligence Division, with full instrumental equipment. Their apparatus cases were nicely balanced at only a few ounces weight each, and the men used their chute capes to ease their drops. We recrossed the river a little distance above and began dropping White Intelligence units and a few long and short range gun units. Then we held our position until we began to get reports. Gradually we ringed the territory of the Sinsings, our observation units working busily and patiently at their locators and scopes, both aloft and aground, until Garlin finally turned to me with the remark: "The map circle is complete now, Boss. We've got clear locations all the way around them." "Let me see it," I replied, and studied the illuminated viewplate map, with its little overlapping circles of light that indicated spots proved clear of the enemy by ultroscopic observation. I nodded to Bill Hearn. "Go ahead now, Hearn," I said, "and place your barrage men." He spoke into his ultrophone, and three of the ships began to glide in a wide ring around the enemy territory. Every few seconds, at the word from his Unit Boss, a gunner would drop off the wire, and slipping the clasp of his chute cape, drift down into the darkness below. Bill formed two lines, parallel to and facing the river, and enclosing the entire territory of the enemy between them. Above and below, straddling the river, were two defensive lines. These latter were merely to hold their positions. The others were to close in toward each other, pushing a high-explosive barrage five miles ahead of them. When the two barrages met, both lines were to switch to short-vision-range barrage and continue to close in on any of the enemy who might have drifted through the previous curtain of fire. In the meantime Bill kept his reserves, a picked corps of a hundred men (the same that had accompanied Hart and myself in our fight with the Han squadron) in the air, divided about equally among the "kite-tails" of four ships.