"bless my dark-lantern! where are you, tom?" called mr. damon as he entered the dim shed where the somewhat frail-appearing aeroplane loomed up in the semi-darkness, for it was afternoon, and rather cloudy. "where are you?"

"here!" called the young inventor. "i'm glad to see you! come in!"

"ah! there it is, eh?" exclaimed the odd man, as he looked at the aeroplane, for there had been much work done on it since he had last seen it. "bless my parachute, tom! but it looks as though you could blow it over."

"it's stronger than it seems," replied the lad. "but, mr. damon, i've got something very important to talk to you about."

thereupon tom told all about mr. sharp's visit, of andy's entry in the big race, and of the suspicions of himself and the balloonist.

"and what is it you wish me to do?" asked mr. damon.

"work up some clues against andy foger."

"good! i'll do it! i'd like to get ahead of that bully and his father, who once tried to wreck the bank i'm interested in. i'll help you, tom! i'll play detective! let me see—what disguise shall i assume? i think i'll take the part of a tramp. bless my ham sandwich! that will be the very thing. i'll get some ragged clothes, let my beard grow again—you see i shaved it off since my last visit—and i'll go around to the foger place and ask for work. then i can get inside the shed and look around. how's that for a plan?"

"it might be all right," agreed tom, "only i don't believe you're cut out for the part of a tramp, mr. damon."

"bless my fingernails! why not?"

"oh, well, it isn't very pleasant to go around in ragged clothes."

"don't mind about me. i'll do it." and the odd gentleman seemed quite delighted at the idea. he and tom talked it over at some length, and then adjourned to the house, where mr. swift, who had seemed to improve in the last few days, was told of the plan.

"couldn't you go around after evidence just as you are?" asked the aged inventor. "i don't much care for this disguising business."

"oh, it's very necessary," insisted mr. damon earnestly. "bless my gizzard! but it's very necessary. why, if i went around the foger place as i am now, they'd know me in a minute, and i couldn't find out what i want to know."

"well, if you keep on blessing yourself," said tom, with a laugh, "they'll know you, no matter what disguise you put on, mr. damon."

"that's so," admitted the eccentric gentleman. "i must break myself of that habit. i will. bless my topknot! i'll never do it any more. bless my trousers buttons!"

"i'm afraid you'll never do it!" exclaimed tom.

"it is rather hard," said mr. damon ruefully, as he realized what he had said. "but i'll do it. bless—"

he paused a moment, looked at tom and his father, and then burst into a laugh. the habit was more firmly fastened on him than he was aware.

for several hours tom, his father and mr. damon discussed various methods of proceeding, and it was finally agreed that mr. damon should first try to learn what andy was doing, if anything, without resorting to a disguise.

"then, if that doesn't work, i'll become a tramp," was the decision of the odd character. "i'll wear the raggedest clothes i can find bless—" but he stopped in time.

mr. damon took up his residence in the swift household, as he had often done before, and for the next week he went and came as he pleased, sometimes being away all night.

"it's no use, though," declared mr. damon at the end of the week. "i can't get anywhere near that shed, nor even get a glimpse inside of it. i haven't been able to learn anything, either. there are two gardeners on guard all the while, and several times when i've tried to go in the side gate, they've stopped me."

"isn't there any news of andy about town?" asked tom. "i should think sam or pete would know where he is."

"well, i didn't ask them, for they'd know right away why i was inquiring," said mr. damon, "but it seems to me as if there was something queer going on. if andy foger is working in that shed of his, he's keeping mighty quiet about it. bless my—"

and once more he stopped in time. he was conquering the habit in a measure.

"well, what do you propose to do next?" asked tom.

"disguise myself like a tramp, and go there looking for work," was the firm answer. "there are plenty of odd jobs on a big place such as the foger family have. i'll find out what i want to know, you see."

it seemed useless to further combat this resolution, and, in a few days mr. damon presented a very different appearance. he had on a most ragged suit, there was a scrubby beard on his face, and he walked with a curious shuffle, caused by a pair of big, heavy shoes which he had donned, first having taken the precaution to make holes in them and get them muddy.

"now i'm all ready," he said to tom one day, when his disguise was complete. "i'm going over and try my luck."

he left the house by a side door, so that no one would see him, and started down the walk. as he did so a voice shouted:

"hi, there! git right out oh heah! mistah swift doan't allow no tramps heah, an' we ain't got no wuk fo' yo', an' there ain't no cold victuals. i does all de wuk, me an' mah mule boomerang, an' we takes all de cold victuals, too! git right along, now!"

"it's eradicate. he doesn't know you," said tom, with a chuckle.

"so much the better," whispered mr. damon. but the disguise proved almost too much of a success, for seeing the supposed tramp lingering near the house, eradicate caught up a stout stick and rushed forward. he was about to strike the ragged man, when tom called out:

"that's mr. damon, rad!"

"wh—what!" gasped the colored man; and when the situation had been explained to him, and the necessity for silence impressed upon him, he turned away, too surprised to utter a word. he sought consolation in the stable with his mule.

just what methods mr. damon used he never disclosed, but one thing is certain: that night there came a cautious knock on the door of the swift home, and tom, answering it, beheld his odd friend.

"well," he asked eagerly, "what luck?"

"put on a suit of old clothes, and come with me," said mr. damon. "we'll look like two tramps, and then, if we're discovered, they won't know it was you."

"have you found out anything?" asked tom eagerly.

"not yet; but i've got a key to one of the side doors of the shed, and we can get in as soon as it's late enough so that everybody there will be in bed."

"a key? how did you get it?" inquired the youth.

"never mind," was the answer, with a chuckle. "that was because of my disguise; and i haven't blessed anything to-day. i'm going to, soon, though. i can feel it coming on. but hurry, tom, or we may be too late."

"and you haven't had a look inside the shed?" asked the young inventor. "you don't know what's there?"

"no; but we soon will."

eagerly tom put on some of the oldest and most ragged garments he could find, and then he and the odd gentleman set off toward the foger home. they waited some time after getting in sight of it, because they saw a light in one of the windows. then, when the house was dark, they stole cautiously forward toward the big, gloomy shed.

"on this side," directed mr. damon in a whisper. "the key i have opens this door."

"but we can't see when we get inside," objected tom. "i should have brought a dark lantern."

"i have one of those pocket electric flashlights," said mr. damon. "bless my candlestick! but i thought of that." and he chuckled gleefully.

cautiously they advanced in the darkness. mr. damon fumbled at the lock of the door. the key grated as he turned it. the portal swung back, and tom and his friend found themselves inside the shed which, of late, had been such an object of worry and conjecture to the young inventor. what would he find there?

"flash the light," he called to mr. damon in a hoarse whisper.

the eccentric man drew it from his packet. he pressed the spring switch, and in an instant a brilliant shaft of radiance shot out, cutting the intense blackness like a knife. mr. damon flashed it on all sides.

but to the amazement of tom and his companion, it did not illuminate the broad white wings and stretches of canvas of an aeroplane. it only shone on the bare walls of the shed, and on some piles of rubbish in the corners. up and down, to right and left, shot the pencil of light.

"there's—there's nothing here!" gasped tom.

"i—i guess you're right!" agreed mr. damon "the shed is empty!"

"then where is andy foger building his aeroplane?" asked tom in a whisper; but mr. damon could not answer him.