The “lookout shack” was in fact a fully-equipped nucleonics laboratory. Its staff was not large—eight men worked in three staggered eight-hour shifts—but the development of its instrumentation had required hundreds of man-years of intensive research. Every factor of the vortex’s activity was measured and recorded continuously, throughout every minute of every day of every year; and all of these measurements were summed up, integrated, into the “sigma” curve. This curve, which to the layman’s eye was only a senselessly zig-zagging line, told the expert everything he wanted to know. Cloud glanced at the chart and scowled, for one jagged peak, less than half an hour old, almost touched the top line of the paper. “Bad, huh, Frank?” “Bad, Storm, and getting worse. I wouldn’t wonder if ‘Calamity’ were right—it certainly looks like she’s getting ready to blow her top.” “No equation, I suppose,” Strong said. The Lensman ignored as completely as did the observer, if not as flippantly, the distinct possibility that at any moment the observatory and all that it contained might be resolved into their sub-atomic components. “None,” Cloud stated. He did not need to spend hours at a calculating machine; at one glance he knew, without knowing how he knew, that no equation could fit that wildly-shifting sigma curve. “But most of these recent cycles cut ordinate seven fifty, so I’ll take that for my value. That means nine point nine six zero kilograms of duodec for my basic, and nine four six two and ten point three five eight as alternates. On the wire?” “It went out as you said it,” the observer replied. “They’ll be here in five minutes.” “QX. I’ll get dressed, then.” The Lensman and one of the observers helped him into his cumbersome, heavily-padded armor; then all three men went out to the flitter. A tiny speedster, really; a slim torpedo with the stubby wings and the ludicrous tail-surfaces, the multifarious driving-, braking-, side-, top-, and under-jets so characteristic of the tricky, cranky, but ultra-maneuverable breed. Cloud checked the newly installed triplex launcher, made sure that he knew which bomb was in each tube, and climbed into the tiny operating compartment. The massive door—flitters are too small to have airlocks—rammed shut upon its teflon gaskets, the heavy toggles drove home. A heavily-padded form closed in upon the pilot, leaving only his left arm and his right leg free to move. “Everybody in the clear?” “All clear.”