The inventor was greatly excited over the news borne to him by the new foreman.  Together they hurried to the Farnum yard, unlocked the door to the submarine’s shed, entered and made a hasty examination.

Thanks to the promptness of Jack Benson and Hal Hastings, Josh Owen had not had time to inflict more damage to the forward sea-valve than could be readily repaired.

“I guess that was what the infernal rascal meant when he told Jack Benson that the ‘Pollard’ would dive to the bottom and stay there,” exclaimed the inventor, in a shaking voice.  He smiled a ghastly smile.

“We’ll put a stop to such pranks after this,” replied the new foreman.  “Until your craft is launched, sir, I’ll sleep here nights, beginning with what’s left of to-night.”

Before the inventor left the yard, he hunted for and found the drunken night watchman, who was still asleep.  That worthless guard was discharged the following day.

CHAPTER V

ONE MAN’S DUMFOUNDED FACE

When the new foreman’s gang started on the “Pollard,” at eight in the morning, there was no outward ripple to show that anything unusual had happened.  True, Jacob Farnum arrived at the shed earlier than he was accustomed to do, but those of the workmen who were not in the secret thought nothing of that.

Half an hour later Josh Owen, a peculiar, gleaming look in his eyes, showed his head at the manhole opening over their heads.

“Good morning, Mr. Farnum,” he called.

“Good morning, Owen,” answered the yard’s owner.  “Come right down.”

Owen came down the spiral staircase, looking curiously about him.

“I got your note, Mr. Farnum,” began the ex-foreman.  “What’s the matter?  Find you need me here, after all?”

“Not for long,” replied Mr. Farnum, coldly.  “Owen, before you gave your keys in to Mr. Partridge you must have taken an impression of one of them and must have fitted a key to the pattern.  Why were you here last night?”

“Me?  I wasn’t here last night—­nor any other night,” Josh Owen made haste to answer, though a look of guilty alarm crept into his face.  All of the workmen had ceased their toil, and stood looking on at this unusual scene.

“You say you weren’t here last night?” demanded Mr. Farnum, sternly.  “And you didn’t use any false key to get into this shed?”

“Of course I didn’t,” retorted the ex-foreman, defiantly.  “You wrote a note to me that, if I’d come around here this morning, I’d hear of a job.  I didn’t come here to be insulted.”

“The job I mentioned in my note,” rejoined Mr. Farnum, with a meaning smile, “is over at the penitentiary.  Owen, you did come here last night.  You scaled the fence at the west side, crossed the yard, opened the door of this building with this key—­”

Here the yard’s owner held out the false key, that all might see it.