Both Curt and Al listened eagerly while Bob related the details of the
Sunday conference with the detective.
He gave them the information imparted by Barney.
“Not a thing wrong with the Silver Flash?” repeated Al. “Then that brown
crate must have driven it down—but why?”
“Maybe some revengeful pilot Mr. Tredway had discharged,” suggested
Curt. “At any rate there must have been some motive to make a man do
anything as terrible as that. But how are we going to locate the brown
“I still have that message we discovered on the seat, and then picked up
in the dewy grass.” Al produced it, dry but smudged and crumpled, from
his pocket card and identification case. “We might compare the writing
with the—well, say with the books in the aircraft plant, and with
everybody’s writing.”
“Lang didn’t get any information when we made inquiries about the brown
craft at the nearest airport, did he?” Lang, who was quite affable and
good-humored, with Griff and his actions forgotten in the new search,
answered Curt.
“No, nothing more than you did. They’d never heard of the ship I
“_You_ have got me more puzzled than this whole mystery has,” Al said,
grinning. “Lang, the way Bob tells it, you must have been next door to
ordering the undertaker, and then you were flying, stunting, as if you’d
never eaten fish and ice-cream.”
“That’s psychologically explainable,” Lang liked to use long words, to
indicate his superiority. “Under the stimulus of——”
“Never mind!” Al threw up his hands as if to ward off a flow of words
too long for his youthful understanding.
“It’s too easy to explain,” Bob said. “Father said Lang got so excited
that he forgot to think about himself, and ‘Nature took its course’ when
he stopped worrying about his fears.”
“That was it,” agreed Lang. “I accepted the idea, from somewhere, that
ice-cream and fish made poison, and while I was flying, when a little
gas began to bother me I got scared, and the scare did the rest. Uncle
said that half our pains are due to believing what other folks tell us
can happen; the rest is from being afraid it is happening to us!”
“That clears it up.” Al became very sober. “I wish the disappearance of
Mr. Tredway was as easy to settle.”
“Well, we’ll have to find that mysterious brown ’plane, or get hold of
somebody who saw it flying, to tell us which way it went.” Lang rose,
stretched, yawning, and sauntered off toward his wheel; the other three,
sitting on the cottage porch before supper, for which Lang would not
stay, looked after him in silence.
“Do you know what I think?” Curt broke the thoughtful pause. “I don’t
mean to criticise, and I don’t want you fellows to get angry, but I have
a feeling that Uncle Fred is wrong to have us drop all our suspicions
and try to find a crate that could be five hundred miles away, in any
direction. My theory is that if we locate the airplane it will be by
‘luck’ and I don’t believe in ‘luck’ because if you think ‘luck’ is
going to help, you don’t have to do anything yourself, and if you
believe it is going to hinder, there’s no use in doing anything. So,” he
grinned, “I believe that everything comes out right only when we do
everything we can to make it so—and as long as there isn’t any way to
start hunting that brown crate, let’s——”
“Disobey?” asked Bob, rather surprised.
“I guess it would amount to that—and in another way it wouldn’t!”
“How could it if it didn’t and why wouldn’t it if it did?”
The others laughed at Al’s twisted inquiry.
“Uncle Fred didn’t give you orders to ‘lay off’ watching, did he, Bob?”
and as Bob shook his head, “He only meant for us to concentrate on
seeing if we could pick up a clue to the mysterious ’plane. Well, I feel
that by finding out what Griff is doing, and why his father is so
fidgety and furtive, and the rest of the puzzles here, we may be led to
that ’plane, or get a clue to it or to its pilot.”
“I don’t see any disobedience in that.”
“Well,” Curt answered Bob, “the way I look at it, if Uncle Fred took us
into the case he expected us to obey the ‘spirit’ of the orders he gave,
and he did say to forget the smaller things here and work on locating
the ’plane.”
“I see,” agreed Bob. “It’s a pretty deep—what Lang would call, ethical
problem. Father meant to leave Griff alone, unless he did something
actually incriminating, and to put all our effort on the other thing.
Let’s see your paper, Al.” He held out his hand for the brief note Al
had preserved.
Study it as they would, they got nothing helpful from the grass-stained
paper with the smudged writing.
“Let’s think who we’ve seen use an indelible pencil,” hinted Al.
“Remember, the morning we found this, we decided, in a joke, that there
were too many indelible pencils to try to trace the writer because he
used one; but how many people close to this mystery have you seen using
“The clerk in the supply room!” gasped Curt.
“Are you sure?”
“Yes, Bob—because he takes a copy of every order he writes and of every
requisition, on an old-fashioned letter press, the same way they put
their copying ribbon letters in between a damp cloth and a soft, thin
sheet of the big book, put it all in the press and make the copying
ribbon print the letter into the book instead of using carbon paper!”
“Then we have a clue! How does the clerk’s writing compare with this?”
“Let’s see!”

Each of the three having spoken in turn, by common consent they agreed
to Al’s impulsive suggestion. They were hardly able to wait for their
supper; however, they put it away with speed if not with the best of
table manners and secured their bicycles.
It took them only a short time to reach the aircraft plant.
The watchman accepted their explanation that they were passing and
wanted to borrow several books from Mr. Tredway’s reference library, in
the offices.
Bob, accordingly, went to the offices, while Curt and Al strolled, with
apparent aimlessness, across the inner quadrangle.
“There’s a light in one window—no, in two windows—already!” Al
mentioned. “I wonder who’s here, at night again.” Almost at once he
suggested that they go and see.
Curt, himself fired by the curiosity of his companion, hurried after Al.
They saw Bob, who had lighted the outer office electric bulbs, choosing
several volumes from a shelf, to carry out in truth their explanation to
the watchman.
“Now—who’s here?” Bob said, joining the others at the door as he put out
the light.
“Can’t be Barney—unless he came back—no, the cabin ’plane isn’t here,”
Al argued. “Anyway, Barney stayed over to transact some business, you
said, Bob. Must be either——”
“Griff, or Griff and his father—or Mr. Parsons and somebody else,” Curt
said breathlessly, excited. “There were two separate offices lighted,
and you can see the door glass shining.”
“The doors are shut, though,” Al spoke, disappointedly.
“Yes,” continued Curt, “but one of us can hide in the alcove where the
water cooler and door to the washroom are located. If anybody comes, it
would be easy to dodge on into the washroom and no one would ask
questions about that.”
“Then you’re elected!” Bob said. “I want to go with Al, because I think
I know where to find the latest letter-book.”
With the reference volumes tucked under his arm he led Al down the dim
corridor, while Curt secured a good place in the niche by the water
cooler to watch from.
As the two brothers went down the steps, at the rear, toward the supply
room, to be sure that no one was there and likely to come up and catch
them, Al’s grip on Bob’s arm tightened convulsively.
Some one was coming down the steps behind them.
With lips close to Al’s ear, Bob whispered:
“Tiptoe! Come on!”
He led Al down to the lowest steps, and there, just beside the door to
the supply room the brothers flattened themselves against the wall.
They held their breath. They made themselves as small as they could. A
quick tread came on down the steps, there was the pause of a body
close—almost touching them. Breathing, sharp, short, quick, carried to
their ears; but they kept mouse-still. The door opened.
A light flared up as Bob dragged Al back out of range. But as they
turned and stared down, hearts still pounding from the excitement of the
narrow escape, both brothers gasped.
In the light below, stood—a bearded stranger!