In suppressed excitement he asked, "When was Smith here, Mr. Black? What time?"

The manager smiled sardonically, and turned back to his work. "No; you can't fasten it on Smith," he said shortly. "It was after he went out that I returned the box to the safe. But, if it's any good to you--he was in here from about five-thirty to ten minutes to six, and was talking with one of the boys in the outer office when I left."

"And Mr. Black, were you outside during the time Smith was in here?"

"No, I--Yes, I was, too. About a quarter to six I was over at the speaking-tube for a minute.

"But enough of this nonsense," the manager added sharply. "The box was in the safe when I closed it. Don't bother me any further with your pretense of investigating. I don't believe it is sincere."

Despite this cutting declaration Jack turned away with secret satisfaction.

Just outside the office door he made a second discovery--a small one, but one which further strengthened the theory he had formed.

It was a small coal cinder and an ash stain in the shape of a heel, apparently overlooked by a careless sweeper.

They could only have been left by a foot which came from the cellar!

Promptly Jack turned toward the cellar door, and made his way down into the big bas.e.m.e.nt.

Going directly to one of the rear windows, he carefully examined it. The cobwebs and the dust on the sill had not been disturbed for months.

He turned to the second, and instantly emitted a shrill whistle of delight. Its cobwebs had been torn and swept aside, and the ledge brushed almost clean. And evidently but a short time before, for the cleared s.p.a.ce showed little of the dust which constantly filtered through the floor above.

"Fine!" exclaimed Jack. "Now I--" He paused. The window was securely latched on the inside!

For several minutes Jack stood, disappointed and mystified. Then, examining the latch closely, he laughed, and grasping it with his fingers, easily pulled it out. It had been forced from the outside, and merely pressed back into the hole.

But its being replaced showed that the intruder had not made his escape that way.

Jack began an examination of the end of the cellar under the express office. And the exit was soon disclosed.

The dividing wall was of boarding, and at the outer end, to facilitate the examination of the gas metres of the two companies, was a narrow door. Ordinarily this door was secured on the telegraph company's side by a strong bolt.

The bolt was drawn, and the door swung easily to Jack's touch!

On the farther side all was darkness, however, and Jack returned to the window. As he approached it something on the floor beneath caught his eye. It was a lead-pencil. He picked it up, and with a cry of triumph discovered stamped upon it the initials and miniature crest of the express company. And, more, a peculiar long-pointed sharpening promised the possibility of fixing its actual owner.

Filled with elation, and confident that it was now only a matter of time when he should clear himself, Jack hastened up-stairs, determined to pursue his investigation next door, where he knew several of the younger clerks.

"h.e.l.lo, Danny," he said, entering the express office, and addressing a sandy-haired boy of his own age. "Say, who in here sharpens pencils like this?"

"h.e.l.lo! That? Oh, I'd know that whittle a mile off. We call 'em daggers--Smith's daggers. Where did you get it?"

"Smith! Who wants Smith?"

Jack turned with a start. It was the clerk himself.

Instantly Jack extended the pencil. "Is this yours, Mr. Smith?" he asked, and held his breath.

"Yes, it is. Where did you find--" Suddenly the clerk turned upon Jack with a look of terror in his face. But in a moment he had recovered himself, and abruptly s.n.a.t.c.hing the pencil from Jack's hand, proceeded to his desk.

Jack was jubilant. Nothing could have been more convincing of the clerk's guilt. Following this feeling, however, came one of pity for the unfortunate man; and after a silent debate with himself, Jack followed him.

Placing a hand on the clerk's shoulder, he said in a low voice:

"Mr. Smith, I have found out about that cash-box of ours. Now look here, why not confess the wretched business before it is too late, and--"

The clerk spun about. "Cash-box! Business! What do you refer to?"

"Mr. Smith, it was you took our cash-box last night."

The clerk was colorless, but he only faltered an instant. "What nonsense is this?" he demanded angrily. "I never heard of your cash-box. What do you mean by--"

"Well then, I'll tell you just how you did it," said Jack determinedly.

"While you were in Mr. Black's office yesterday afternoon he stepped out and left you alone for a moment. The cash-box was on the table. You immediately saw the opportunity (perhaps Hansen had done the same thing, and put you onto it?)--you saw the opportunity, and threw over the box a newspaper you had in your hand. As you had hoped, not seeing the box, Mr.

Black forgot it, and left at six o'clock without returning it to the safe. You made sure of that by remaining about the outer office until he left. And then, after midnight you came down to the office here, forced an entrance into our cellar, and went up-stairs and secured the box.

"I'm sorry--but isn't that so?"

The clerk laughed drily. "The great Mr. Sherlock Holmes, junior!" he remarked sarcastically. "Rubbish. Run away and don't bother me with your silly detective theories," and turned back to his desk.

Jack stood, baffled and surprised.

[Ill.u.s.tration: THE CLERK WAS COLORLESS, BUT ONLY FALTERED AN INSTANT.]

"Look here, Orr!" As Smith again spun about a hard look came into his face. "Look here, how do you come to know so much about this business, yourself? Eh?"

Jack uttered an exclamation, and a sudden fear of the clerk came over him. Was Smith thinking of trying to place the blame upon him?

However, further discussion was clearly useless, and he turned away.

The following morning brought quick proof that Jack's suddenly inspired fear of Smith was too well founded. As he entered the telegraph office Mr. Black called him and handed him a note. "Now what have you to say?"

he demanded solemnly.

In a lead-pencil scrawl Jack read:

"Mr. Black: Your yung operatur Orr can tell you sumthin about thet cash box, he was showin the key of the box to sumone yesteday and i saw him. Mebee you will finde the key in his offis cote.

"Yours, a frend."

"It is the key," said the manager, producing a small key on a ring. "I recall having left it in the lock."

Jack stood pale and speechless. Despite the disguised writing and poor spelling, the letter was from Smith, he had not a doubt. But how could he prove it? Truly matters were beginning to look serious for him.

Quickly, however, Jack's natural spirit of fight-to-the-end returned to him, and handing the letter back, he said, respectfully but determinedly, "Mr. Black, I still hold you to your promise to give me a week in which to prove my innocence. And I'll prove, too, sir, that this key was placed in my pocket by someone else, probably by the one who really took the box. I believe I know who it is, but I'll prove it first."

Reluctantly the manager consented, for he now firmly believed at least in Jack's complicity; and leaving him, Jack sought the operating-room, to spend every spare moment in turning the matter over in his mind.