"what's the matter, tom?" asked mr. sharp, as the lad came hurrying along the roof, having taken the precaution to fasten the scuttle door as well as he could. "you seem excited." "so would you, if you had heard what i did."

"what? you don't mean that some of the gang is down there?"

"yes, and what's more i'm on the trail of the thieves who robbed the shopton bank of the seventy-five thousand dollars!"

"no! you don't mean it!"

"i certainly do."

"then we'd better tell mr. damon. he's in the cabin."

"of course i'll tell him. he's as much concerned as i am. he wants to be vindicated. isn't it great luck, though?"

"but you haven't landed the men yet. do you mean to say that the same gang—the happy harry crowd—robbed the bank?"

"i think so, from what i heard. but come inside and i'll tell you all about it."

"suppose we start the ship first? it's ready to run. there wasn't as much the matter with it as i feared. the storm is over now, and we'll be safer up in the air than on this roof. did you get all the information you could?"

"all i dared to. the men were coming out, so i had to run. they were quarreling, and when that happens among thieves—"

"why honest men get their dues, everyone knows that proverb," interrupted mr. damon, again emerging from the cabin. "but bless my quotation marks, i should think you'd have something better to do than stand there talking proverbs."

"we have," replied mr. sharp quickly. "we're going to start the ship, and then we have some news for you. tom, you take the steering wheel, and i'll start the gas machine. we'll rise to some distance before starting the propellers, and then we won't create any excitement."

"but what news are you going to tell me?" asked mr. damon. "bless my very existence, but you get me all excited, and then you won't gratify my curiosity."

"in a little while we will," responded mr. sharp. "lively now, tom. some one may see this airship on top of the building, as it's getting so much lighter now, after the storm."

the outburst of the elements was almost over and tom taking another look over the edge of the roof, could see persons moving about in the street below. the storm clouds were passing and a faint haze showed where a moon would soon make its appearance, thus disclosing the craft so oddly perched upon the roof. there was need of haste.

fortunately the red cloud could be sent aloft without the use of the propellers, for the gas would serve to lift her. it had been found that lightning had struck the big, red aluminum container, but the shock had been a comparatively slight one, and, as the tank was insulated from the rest of the ship no danger resulted to the occupants. a rent was made in two or three of the gas compartments, but the others remained intact, and, when an increased pressure of the vapor was used the ship was almost as buoyant as before.

into the cabin the three travelers hurried, dripping water at every step, for there was no time to change clothes. then, with tom and mr. sharp managing the machinery, the craft slowly rose. it was well that they had started for, when a few hundred feet above the roof, the moon suddenly shone from behind a bank of clouds and would most certainly have revealed their position to persons in the street. as it was several were attracted by the sight of some great object in the air. they called the attention of others to it, but, by the time glasses and telescopes had been brought to bear, the red cloud was far away.

"dry clothes now, some hot drinks, and then tom will tell us his secret," remarked mr. sharp, and, with the great ship swaying high above the city of middleville tom told what he had heard in the office building.

"they are the thieves who looted the bank, and caused us to be unjustly accused," he finished. "if we can capture them we'll get the reward, and turn a neat trick on andy foger and his cronies."

"but how can you capture them?" asked mr. damon. "you don't know where they are."

"perhaps not where morse and the men who have the money are. but i have a plan. it's this: we'll go to some quiet place, leave the airship, and then inform the authorities of our suspicions. they can come here and arrest the men who still seem to be hanging out in morse's office. then we can get on the trail of this shagmon, who seems to be the person in authority this time, though i never heard of him before."

"he seems to have the money, according to what one of the men in the office said, and he's the man we want."

"shagmon!" exclaimed mr. damon. "yes, shagmon. the fellow i heard talking 'said he'd go to shagmon and make morse whack up. shagmon may be the real head of the gang."

"ha! i have it!" cried mr. damon suddenly. "i wonder i didn't think of it before. shagmon is the headquarters, not the head of the gang!"

"what do you mean?" asked tom, much excited.

"i mean that there's a town called shagmon about fifty miles from here. that's what the fellow in the office meant. he is going to the town of shagmon and make morse whack up. that's where morse is! that's where the gang is hiding! that's where the money is! hurrah, tom, we're on the trail!"