With that he whipped off his bifocals and stalked out. Ten seconds later he stalked back, prodded by the business end of a neuroblast rifle in the hands of a cold-eyed MP. "Refusal to aid your country at such a time," Three-star Corbin pointed out, "is a treasonable action, punishable by indefinite imprisonment." Two-star Demarest gave him the other barrel. "Stubbornness will gain you nothing, Doctor. Have you considered that our serum-and-psycho corps can easily extract the necessary information from you?" Hard-headed as he was, the Doc read the handwriting on the wall without even adjusting his bifocals. "You may change your minds after seeing the Subspace Twisters," he said. "Activate the model, Gerald." I flipped the switch on the three-foot bakelite cabinet that housed our little Di-tube generator. It sizzled for a moment with a sound like frying bacon and shot out a two-inch beam from the copper helix at the bottom--a beam as clearly outlined as a water pipe but which couldn't really be seen because there was nothing there. Don't let that throw you. Just take my word for it--it was a two-inch cylinder of nothing at all, a clean-cut shaft of absolute vacancy. Until you looked into the twin-prism eyepiece we had rigged up, that is. You couldn't sight directly down the tube itself because the generator's energy feedback raised a glowing force-bubble that hung above the cabinet like a basketball-sized neon bulb. That bubble represented a spherical strain against superspace, so Doc said, in compensation for the forced passage of the Di-tube through the continuum of subspace. A demonstration of the first law of physics, to every action an equal and opposite reaction. Three-star Corbin looked first, pulling his rank. One glimpse of the Twisters was enough--he jumped a foot and turned the color of a dead flounder. "In God's name," he choked when he got his breath back, "what _are_ they?" "We don't know," I told him. "But I'll give you odds that they wouldn't be chummy if they ever got up here." I knew how he felt. My first sight of the Twisters had given me nightmares for a week. I won't try to describe them because they never looked alike to any two people. Doc said that a description didn't matter because what we thought we saw were only multidimensional cross-sections anyway--but I wouldn't know about that. To me they looked like inside-out octopuses. "You see?" Doc snapped, bristling his beard triumphantly. "The cross-sections we see of these inhabitants of subspace give no clue whatever as to their true nature. Even you should realise that opening a larger rift into their domain would be an extremely dangerous undertaking." "Allied Military," said Three-star Corbin, who had got some of his color back, "is quite capable of dealing with these brutes if necessary. Dr. Maxey, you will proceed with the construction of a full-scale Dimension-tunnel." The doc made some sulphurous remarks that were lost in his beard.