The situation was critical. That the wild-eyed visitor was demented, there was hardly a doubt, but his madness was of a most dangerous character.

The eyes of all were fixed with terror upon the innocent-looking valise which he held in his left hand, and in the mind of all was the terrible thought, Dynamite!

"Well, will you give me the money?" demanded the crank fiercely.

"I—I don't think I have as much money in the office," stammered the pallid banker.

"That won't work," exclaimed the visitor angrily. "If you can't find it I will send you where you won't need money," and he moved his arm as if to throw the valise on the floor.

"I—I'll give you a check," faltered Luther Rockwell, the banker.

"And stop payment on it," said the crank with a cunning look. "No, that won't do."

"Give me half an hour to get the money," pleaded Rockwell desperately. "Perhaps twenty minutes will do."

"You would send for a policeman," said the intruder. "That won't do, I must have the money now. Or, if you haven't got it, bonds will answer."

Luther Rockwell looked helplessly toward the two clerks, but they were even more terrified than he. There was one to whom he did not look for help, and that was the telegraph boy, who stood but three feet from the crank, watching him sharply. For a plan of relief had come into the mind of Mark Mason, who, though he appreciated the danger, was cooler and more self-possessed than any one else in the office.

Standing just behind the crank, so that he did not attract his attention, he swiftly signaled to the clerks, who saw the signal but did not know what it meant. Mark had observed that the dangerous satchel was held loosely in the hands of the visitor whose blazing eyes were fixed upon the banker. The telegraph boy had made up his mind to take a desperate step, which depended for its success on rapid execution and unfaltering nerves.

Luther Rockwell was hesitating what reply to make to his visitor's demand when Mark, with one step forward, snatched the valise from the unsuspecting visitor and rapidly retreated in the direction of the two clerks.

"Now do your part!" he exclaimed in keen excitement.

The crank uttered a howl of rage, and turning his fierce, bloodshot eyes upon Mark dashed towards him.

The two clerks were now nerved up to action. They were not cowards, but the nature of the peril had dazed them. One was a member of an athletic club, and unusually strong.

They dashed forward and together seized the madman. Mr. Rockwell, too, sprang from his seat, and, though an old man, joined the attacking party.

"Quick!" he shouted to Mark. "Take that valise out of the office, and carry it where it will do no harm. Then come back!"

Mark needed no second bidding. He ran out of the office and down-stairs, never stopping till he reached the nearest police station. Quickly he told his story, and two policemen were despatched on a run to Mr. Rockwell's office.

They arrived none too soon. The crank appeared to have the strength of three men, and it seemed doubtful how the contest between him and the three who assailed him would terminate.

The two policemen turned the scale. They dexterously slipped handcuffs over his wrists, and at last he sank to the floor conquered. He was panting and frothing at the mouth.

Luther Rockwell fell back into his seat exhausted.

"You've had a trying time, sir!" said one of the policemen respectfully.

"Yes," ejaculated the banker with dry lips. "I wouldn't pass-through it again for fifty thousand dollars. I've been as near a terrible death as any man can be—and live! But for the heroism of that boy—where is he?"

The question was answered by the appearance of Mark Mason himself, just returned from the police station.

"But for you," said the banker gratefully, "we should all be in eternity."

"I too!" answered Mark.

"Let me get at him!" shrieked the crank, eying Mark with a demoniac hatred. "But for him I should have succeeded."

"Was there really dynamite in the bag?" asked one of the policemen.

"Yes," answered Mark. "The sergeant opened it in my presence. He said there was enough dynamite to blow up the biggest building in the city."

"What is going to be done with it?" asked the banker anxiously.

"The policemen were starting with it for the North River."

"That's the only safe place for it."

"If you have no further use for this man we'll carry him to the station-house," said one of the officers.

"Yes, yes, take him away!" ejaculated the banker with a shudder.

Struggling fiercely, the crank was hurried down the stairs by the two official guardians, and then Mr. Rockwell who was an old man, quietly fainted away.

When he came to, he said feebly, "I am very much upset. I think I will go home. Call a cab, my boy."

Mark soon had one at the door.

"Now, I want you to go with me and see me home. I don't dare to go by myself."

Mark helped the old gentleman into his cab, and up the stairs of his dwelling. Mr. Rockwell paid the cab driver adding. "Take this boy back to my office. What is your name, my boy?"

"Mark Mason, No. 79."

Luther Rockwell scribbled a few lines on a leaf torn from his memorandum book, and gave it to Mark.

"Present that at the office," he said. "Come round next week and see me."

"Yes, sir," answered Mark respectfully, and sprang into the cab.

As he was riding through Madison Avenue he noticed from the window his uncle Solon and Edgar walking slowly along on the left hand side. At the same moment they espied him.

"Look, father!" cried Edgar in excitement "Mark Mason is riding in that cab."

"So he is!" echoed Mr. Talbot in surprise.

Catching their glance, Mark smiled and bowed. He could understand their amazement, and he enjoyed it.

Mechanically Mr. Talbot returned the salutation, but Edgar closed his lips very firmly and refused to take any notice of his cousin.

"I don't understand it," he said to his father, when the cab had passed. "Doesn't it cost a good deal to ride in a cab in New York?"

"Yes. I never rode in one but once, and then I had to pay two dollars."

"And yet Mark Mason, who is little more than a beggar, can afford to ride! And last evening he was at the theater in company with a fashionable young lady. Telegraph boys must get higher pay than he said."

"Perhaps, Edgar," suggested his father with an attempt at humor, "you would like to become a telegraph boy yourself."

"I'd scorn to go into such a low business."

"Well, I won't urge you to do so."

Meanwhile Mark continued on his way in the cab. As he passed City Hall Park Tom Trotter, who had just finished shining a gentleman's boots, chanced to look towards Broadway. As he saw his friend Mark leaning back in the cab, his eyes opened wide.

"Well, I'll be jiggered!" he exclaimed. "How's that for puttin' on style? Fust thing you know Mark Mason will have his name down wid de Four Hundred!"

It did not occur to Mark to look at the paper given him by Mr. Rockwell till he got out of the cab.

This was what he read:

Mr. Nichols: Give this boy ten dollars.

Luther Rockwell.