Then Captain Bartlot came striding back, his jaw set, his bronzed face tinged an angry red.

At his command, a couple of stationary engines, housed on either side of the building, were set to generating. Under their power the huge curved doors began to roll back, each door moving on twenty steel wheels on a curved track that carried it back along the side of the building. As he stepped forward and took a view down that vast vault, Lee Renaud felt reduced to smallness—of a truth! As he looked upward, there was a sense of surrounding immensity that left him weak in the legs. Two hundred feet up, under the ridge of the roof, toy workmen labored on a duralumin framework that had been lifted up by cranes. Not a sound came from them, they were too far away.

Lee Renaud caught his breath. Within this mountain of steel and glass, six football games, a chariot race and a circus could be staged simultaneously.

“The largest building in the world without internal supports or columns of any kind,” said Jan Bartlot, “and er-r, the only building in the world that has its own peculiar brand of weather. Ah—ca-chu-ah!” the Captain ended in a wild sneeze as a heavy shower rained down upon them.

Lee looked about in puzzlement. The sun was shining brightly outside.

“Condensation,” explained Bartlot. “All sorts of temperatures meet in here, form a fog, and occasionally roll down in rain.”

“But the Nardak? I thought it was housed in here?” Lee cast his gaze over the vast emptiness.

“She’s coming in now. Don’t you hear the buzzer?”

“Bz-z-z!” A radio within the building had picked up the signal from the approaching ship. Men rushed forward from all sides and took their stands at stated intervals along the length of the building.

From the magazine illustrations he had seen of dirigibles, Lee Renaud pictured to himself how the Nardak would come—an elongated balloon drifting through the air, casting off thousand-foot lengths of rope for men to seize and drag her down to earth.