The lighthouse on Cape Morrow swept its beam across the harbor grid each night, illuminating one column at a time as the lamp rotated. Monday the beam lit the leftmost column, Tuesday the next, Wednesday the center. The keeper expected Thursday's beam on the fourth column. But the generator failed that night — no fuel, no spark, nothing — and the entire grid went dark. Not a single cell lit. The supply boat came Friday and the light resumed, catching up to where it should have been.