Just out, side the door of Midshipmen Farley and Page there lay on the floor tiny glass fragments of what had been an efficient sixty-candle-power tungsten electric bulb.

It was one of the lights that illuminated the corridor.
Now one of these tungsten bulbs, when struck smartly, explodes with a report like that of a pistol.
At this hour of the night, however, there were none passing save Naval officers on duty.

None other than the lieutenant himself had lately passed in the corridor.

How, then, had this electric light bulb been shattered and made to give forth the sound of the explosion?
"It wouldn't go up with a noise like that," murmured the lieutenant to himself.

"These tungsten lights don't explode like that, except when rapped in some way.