The bundle was two outfits such as the stranger wore. They donned them as instructed; the hoods were stiff with wire, and connected by a flexible cord to the packs. Manning eyed the gun speculatively; the masked man explained softly, "It's not that I don't trust you, but those gadgets are too valuable to take _any_ chances with. They're invisibility units. Start them by pressing here." He pulled down one of the levers on his pack; he seemed to blur slightly, but they could still see him. "The headgear insulates you pretty well from the effect. Go on, start those units!" Heavy feet were thundering overhead on the bridge planks. They obeyed; the packs made a faint hum. The stranger relaxed visibly. "Now we're okay," he said in a normal voice. "By the time they catch on, we'll be a long way from here." Directly above, an angry snarl: "_Sie sind grade ins Wasser gesprungen! Wer hatte erwartet--_" Somebody else answered, "_Vielleicht wird ein Boot dort unten gelegen haben_." "Good guessing," approved the masked man cheerfully. He motioned Manning and Dugan toward where a small skiff lay beached between the piles. "Help me launch this. First, though, turn your units up to full power--like this--so they'll cover the boat." Manning was startled at the man's bravado; as all three laid hold of the boat, he whispered anxiously, "Won't they hear--" "Not if we shouted our heads off," the other answered. "With these units going, we're not only invisible, but inaudible and practically intangible. I've walked through a cordon that was closing in on me with linked arms." He sprang nimbly into the bow of the boat. "Grab an oar, you two, and make yourselves useful. I've been through a lot of trouble on your account." He seemed to decide that introductions were finally in order. "My name's Jerry Kane. At any rate, it's my favorite alias." Manning and Dugan named themselves and fell to rowing. "Downstream," said Kane, and he gazed back at the bridge with interest as they pulled away. Manning glanced back over his shoulder; there were dark figures swarming on the bridge, and lights, and a car had stopped there; even as he looked a searchlight beam swayed out across the water, moving systematically back and forth. For a moment it fell full upon the rowboat, and Manning ducked involuntarily; but the light passed on and there was no outcry, no shots came. Manning said hoarsely, "That light was on us! It didn't go through us, or anything of the sort. A body that reflects light is visible. So how the devil--"