ow was knit, just as when he used carefully and anxiously to
move the grass away from an all but obliterated footprint, and his eyes
were half closed and keen.

"I know what it is," he said to himself, suddenly. "It means how light
can be passed through a room even while the room is dark all the
time--kind of reflected--and you wouldn't have to use any match."

He stood still, almost frightened at his own conclusion. The clean,
shiny mess plate and the phrase out of that letter seemed to fit
together like the sections of a picture puzzle. The black spot and the
match-end (if there was any match-end) meant just nothing at all. The
dim light out in the passageway down below hardly reached the dark
staterooms, but----

He could not remember just how it was down there, but he knew that in
the staterooms where the glass ports were locked (and that was the case
with all of the crews' quarters below) air was admitted by a slightly
opened panel transom over the door.

What should he do? Go and tell an officer about his discovery? If it
_were_ a discovery that would be all very well. But after all, this was
only a--a kind of a _deduction_. And they might laugh at him. He had
always stood in awe of the officers and since last night he was mortally
afraid of them. If he told any of the soldiers or even the steward they
would only jolly him. He did not know exactly what he had better do.

He made up his mind that he would go down through the passageway where
those under engineers and electricians slept and see how it looked down
there. He had been through there many times, but he thought that perhaps
he would notice some thing now which would help to prove his theory and
then perhaps they would listen to the captain's mess boy if he could
muster the courage to speak.

He had just left the rail when he saw, some distance to starboard as it
seemed, and well forward of the ship, an infinitesimal bluish brown
spark. How he happened to notice it he did not know. "Once a scout,
always a scout," perhaps. In any event, it was only by fixing his eyes
intently upon it that he could keep it in sight. And even so, he lost it
after a few seconds. He tried to find it again, but quite in vain. It
had been about as conspicuous as a snowflake would have been in a glass
of milk.

"Huh, if there's anyone on this ship can see _that_, he must be a peach.
Maybe up in the rigging you can see it better, though. If it's on the
destroyer, she's quit