Out of the cabin of the now stationary airship hurried the three travelers; out into the pelting rain, which was lashed into their faces by the strong wind. Tom was the first to emerge.  
"We're on something solid!" he cried, stamping his feet. "A rock, I guess."
 
"Gracious, I hope we're not on a rock in the midst of a river!" exclaimed Mr. Damon. "Bless my soul, though! The water does seem to be running around my ankles."
 
"There's enough rain to make water run almost up to our necks," called Mr. Sharp, above the noise of the storm. "Tom, can you make out where we are?"
 
"Not exactly. Is the ship all right?"
 
"I can't see very well, but there appears to be a hole in the gas container. A big one, too, or we wouldn't have fallen so quickly."
 
The plight of the travelers of the air was anything but enviable. They were wet through, for it needed only a few minutes exposure to the pelting storm to bring this about. They could not tell, in the midst of the darkness, where they were, and they almost feared to move for fear they might be on top of some rock or precipice, over which they might tumble if they took a false step.
 
"Let's get back inside the ship," proposed Mr. Damon. "It's warm and dry there, at all events. Bless my umbrella, I don't know when I've been so wet!"
 
"I'm not going in until I find out where we are," declared Tom. "Wait a minute, and I'll go in and get an electric flash lantern. That will show us," for the lightning had ceased with the great crash that seemed to have wrecked the Red Cloud. The rain still kept up, however, and there was a distant muttering of thunder, while it was so black that had not the lights in the cabin of the airship been faintly glowing they could hardly have found the craft had they moved ten feet away from it.
 
Tom soon returned with the portable electric lamp, operated by dry batteries. He flashed it on the surface of where they were standing, and uttered an exclamation.
 
"We're on a roof!" he cried.
 
"A roof?" repeated Mr. Damon.
 
"Yes; the roof of some large building, and what you thought was a river is the rain water running off it. See!"
 
The young inventor held the light down so his companions could observe the surface of that upon which the airship rested. There was no doubt of it. They were on top of a large building.
 
"If we're on a roof we must be in the midst of a city," objected Mr. Damon. "But I can't see any lights around, and we would see them if we were in a city, you know."
 
"Maybe the storm put the lights out of business," suggested Mr. Sharp. "That often occurs."
 
"I know one way we can find out for certain," went on Tom.
 
"How?"
 
"Start up our search lamp, and play it all around. We can't make sure how large this roof is in the dark, and it's risky trying to trace the edges by walking around."
 
"Yes, and it would be risky to start our searchlight going," objected Mr. Sharp. "People would see it, and there'd be a crowd up here in less than no time, storm or no storm. No, we've got to keep dark until I can see what's the matter. We must leave here before daylight."
 
"Suppose we can't?" asked Mr. Damon. "The crowds will be sure to see us then, anyhow."
 
"I am pretty sure we can get away," was the opinion of the balloonist. "Even if our gas container is so damaged that it will not sustain us, we are still an aeroplane, and this roof being flat will make a good place to start from. No, we can leave as soon as this storm lets up a little."
 
"Then I'm going to have a look and find out what sort of a building this is," declared Tom, and, while Mr. Sharp began a survey, as well as he could in the dark, of the airship, the young inventor proceeded cautiously to ascertain the extent of the roof.
 
The rain was not coming down quite so hard now, and Tom found it easier to see. Mr. Damon, finding he could do nothing to help, went back into the cabin, blessing himself and his various possessions at the queer predicament in which they found themselves.
 
Flashing his light every few seconds, Tom walked on until he came to one edge of the roof. It was very large, as he could judge by the time it took him to traverse it. There was a low parapet at the edge. He peered over, and an expanse of dark wall met his eyes.
 
"Must have come to one side," he reasoned. "I want to get to the front. Then, maybe, I can see a sign that will tell me what I want to know."
 
The lad turned to the left, and, presently came to another parapet. It was higher, and ornamented with terra-cotta bricks. This, evidently, was the front. As Tom peered over the edge of the little raised ledge, there flashed out below him hundreds of electric lights. The city illuminating plant was being repaired. Then Tom saw flashing below him one of those large signs made of incandescent lights. It was in front of the building, and as soon as our hero saw the words he knew where the airship had landed. For what he read, as ............