For 317 days, the old constant of the approaching tide had locked every instrument in the world to an outdated scale. At Dam Seven, all six secondary constant instruments flashed red at once. The gravity reading climbed, while the medium's density fell. The forty-seven people beneath the covered walkway had no idea the steel beams overhead were already groaning. Temporary readings clerk Cen Du could have avoided all blame for the collapse if he simply kept quiet about its direction. Instead, he braced himself on the console and leaped from the three-meter-high observation platform just to get a look at those three seconds. He saw the first seven sections of the gate wall buckle inward, all crashing down on the left. Up was not truly up when gravity shifted by a third. His voice hoarse, he shouted for everyone to press against the right wall and cover their heads, dragging all forty-seven people out from under the rubble. He escaped with only a cut on his hand and a twisted ankle, but lost the copper calibration needle his master had left him. Old Tu slipped him half a message slip and said this time didn't count as seeing beyond his limits. But the line of tiny writing on the back wasn't in Old Tu's hand.
