They flung themselves past a last cone building to halt for an instant in utter amazement despite the nearing pursuit. Before them were no more streets and structures, but a huge smooth-flowing waterway! It gleamed in the moonlight and lay at right angles across their path, seeming to flow along the Martian city's edge. "A canal!" cried Lanier. "It's one of the canals that meet at this city and flow around it! We're trapped--we've reached the city's edge!" "Not yet!" Randall gasped. "Look!" As he pointed to the left Lanier shot a glance there; and then both of them were running in that direction, along the smooth metal paving that bordered the mighty canal. They came to what Randall had seen, a mighty metal arch that soared out over the waterway to its opposite side. A bridge! They were on it, were racing up the smooth incline of it. Randall glanced back as they reached the arch's summit. From that height the city stretched far away behind them, a lace of crimson lights in the night. He glimpsed the gleam of the giant waterway that encircled the city completely, one that was fed by other canals from far away that emptied into it, the great city's vital water-supply brought thus from this world's melting polar snows. There were moving lights behind now, too, pouring out onto the metal paving by the waterway, moving to and fro as though in confusion, with a babel of hissing cries. It was not until Randall and Lanier were running down the descending incline of the great arched bridge, though, that the lights and shouts of their pursuers began to move up on that bridge after them. * * * * * Running off the bridge's smooth way, the two found themselves stumbling on through the darkness over more metal paving, and then over soft ground. There were no lights or buildings or sounds of any sort on this farther side of the great waterway. A tall dark wall seemed suddenly to loom up out of the darkness some distance ahead of the two. "The crimson jungle!" Randall cried. "The jungles we glimpsed from the city! It's a chance to hide!" They raced toward the protecting blackness of that wall of vegetation. They reached it, flung themselves inside, just as the pursuing Martians, a mass of running crocodilian shapes and of great racing centipede-machines, swept up over the bridge's arch behind. A moment the two halted in the thick vegetation's shelter, gasping for breath, then were moving forward through the jungle's denser darkness.