It is merely a reflector, made of an old tin can, that increases and concentrates the brilliancy of the candle light.
The "tin can" may also be used in such a way as to throw a large part of a tent in semi-darkness.
Two minutes later, Greg's breathing proclaimed the fact that this cadet was sound asleep.
Dick, stifling a yawn---for it had been a long, hard and busy day---threw a look of envy toward his chum.

Then, in uniform, Prescott stepped out into the company street.
It was a dark, starless night; an ideal night to a plebe who wanted to run the guard and put in some time outside of the camp limits.
Keeping as much in the shadow as he could, Prescott stepped along until he came near one of the sentry lines.
For some time he stood thus, eyes and ears alert, though he lounged in the shadow where he was not likely to be seen.
"It's an off night for plebe mischief, I reckon," he murmured at last.

"All the plebes are good little boys to-night, and safely tucked in their cribs." At last, when it was near midnight, Prescott came out from his place of semi-concealment and stepped over near the guard line.
It was not long ere a yearling sentry, with bayonet fixed and gun resting over his right shoulder, came pacing toward the first classman.
Recognizing a cadet officer, the yearling sentry halted, holding his piece at "present arms." "Walk your post," Dick directed, after having returned the salute.
Had Prescott been a cadet private the sentry would have questioned him as to his reasons for being out after taps.

But with a cadet captain it was different.

Though Prescott was not cadet officer of the day, he was privileged to have official reasons for being out without making an accounting to the sentry.
Slowly the yearling sentry paced down to the further end of his post.