Jack did not remain senseless long. When he recovered he became aware of a confused shouting, and an acrid smell of smoke filled his nostrils.

"Jack! Jack!" he heard Jennie and her mother shouting. "Jack, are you hurt?"

By a great effort, overcoming the faintness that seemed to be returning,
Jack scrambled to his feet. It was dead black in the place now.

"I'm all right!" Jack cried, "but something has happened. They've been here all right Stay up there until I call you."

He struck a match, for he had a box in readiness in his pocket.

A glance into the room where the safe stood showed what havoc had been wrought by the explosion. It was not much, for only a small charge had been used. But the door of the safe was blown off, and some damage was done to the fixtures and furniture of the place.

The interior of the strong box—for it was that and nothing more, being an old-fashioned safe—was plainly exposed to view. Jack was in front of it on the jump. Lighting another match he peered within.

"They're gone!" he cried aloud. "He's got the Argent letters! And me sleeping right beside them! This is fierce!"

With trembling fingers, and a deep sense of humiliation in his heart, Jack lighted a lamp. But even with this greater light there was no trace of the missing packet. Only that seemed to have been taken, as far as Jack could make out.

But now Jennie and her mother, frightened and alarmed, were begging to know what had happened. There was no trace of the masked man. He had slipped out while Jack lay unconscious, our hero thought. Though, indeed, he felt little like a hero just then.

"Oh, Jack, what is it? Can't we come down? Are you hurt?" Jennie begged.

"No, I'm not hurt. Come down if you like. They blew open the safe!"

"Oh!" exclaimed Mrs. Blake, and there was fear and alarm in her voice. Certainly any one might fear those unscrupulous outlaws, who seemed to halt at nothing to gain their ends.

For a moment Jack gazed dumbly at the ruin wrought. His eyes sought for some trace of the package he had done so much to bring through with safety, but which, after all, had been taken while he slept. Certainly it was an unfortunate and distressing affair.

"Oh, isn't it awful!" gasped Jennie, as she and her mother picked their way through the confusion of furniture in the room, and looked at the looted safe. "It's just terrible!"

"Jack, sound an alarm at once!" cried Mrs. Blake, recognizing the need for quick action, "Fire your revolver out of the window—yell—do something!"

"Of course! And here I stand like a booby!" Jack cried. "We must get a posse after that fellow!"

An open window showed how the robber had entered and gone. Jack thrust his weapon outside and fired the five shots in quick succession. The explosion by which the safe was shattered did not appear to have roused any of the townspeople. Probably the report was too muffled to carry far.

But Jack's shots, ringing out in the open, were heard, and soon windows began to go up. Heads were thrust out, and there came many demands to know what was going on.

"Post office safe blown and robbed!" cried Jack. "It was done by one man, though there may have been more. We must get after them!"

"That's what we must!" cried Tim Mullane, one of the first on the scene.

Jack slipped on his shoes, and, with a lantern, hurried across to where Sunger was stabled. As he approached the place the open door made his heart sink.

"If he has taken Sunger—" he faltered.

That was what the masked robber had done. The pony's stall was vacant. Jack felt a fierce longing to do something desperate. This was the last straw.

"Sunger gone! Sunger gone!" Jack repeated, blankly.

He did not want to believe it, but there was nothing else to do. The masked robber had made his escape on Jack's speedy mount.

By this time all those living in the vicinity of the post office were aroused. They came, hastily dressed, mostly men and boys, to crowd into the small place and look at the wrecked safe.

"That job was done by professionals all right," said the town marshal. "That's no amateur work. He just put some of the nitroglycerine in a crack between the door and the casing, or maybe in a hole he bored, and touched it off with a fuse. Yes, it was a neat job."

"Neat!" Jock exclaimed, rather indignantly. "When he took that valuable package? Neat!"

"Oh well, you know what I mean," the marshal said. "Now, boys, we've got to get these fellows, and get after them hard!"

"I only saw one," Jack put in.

"Well, he probably had confederates. Now, boys, get your horses and we'll hit the trail. There's only two he could take, and we'll cover 'em both. You come along, too, Jack, that is if you feel able. I see you got a cut on your head."

Jack put up his hand. It came away bloody, and Jennie screamed.

"It's only a little cut where I fell, when the force of the explosion knocked me down," Jack said. Up to then, so great had been the excitement, he had not been aware of the slight injury.

"Well get on your pony then, and come along," the marshal urged him. "We'll want you to identify the fellow if we catch him. That is if you can."

"I'm not sure I could," Jack said. "I only saw his back, and he wore a mask."

"Well, come along anyhow. Hop on your pony and—"

"I can't!" Jack exclaimed. "The fellow took Sunger!"

"He did!" the marshal cried. "Well, now we certainly must get him! If he's a horse thief, as well as a safe-blower we sure will get him! Scatter, boys! Be lively! Jack, I'll lend you a horse. Come on now. Jim Hickey, you lead one bunch over the Tuckerton trail, and I'll head another on the road to Rainbow Ridge. But most likely the fellow will take to the mountains and hide out for a spell."

"He won't be very likely to go to Rainbow Ridge," said Jack.

"Why not?"

"Because he's got a valuable package of letters and mining documents addressed to Mr. Argent of that place. He wouldn't go there."

"I don't know," returned the marshal. "He wouldn't stay there, but he might go through that way."

It did not take long to organize two posses, and Jack went with the one led by the marshal. The young express rider bestrode a borrowed steed, and though it was good enough, as horses go, it was not at all like his beloved Sunger.

"I wonder if I'll ever get him back," mused the lad, as he trotted along beside the others.

"A measly horse thief!" muttered the marshal. "We'll get him if it takes a year."

In the West horse-stealing is a crime almost on a par with killing; for out there a man's life often depends on his horse, and if a thief takes the horse away he may also be responsible for the death of the man. That is why horse-stealing is visited with such swift and sure vengeance when the culprit is caught.

Since there was a moon that night, there was fairly good light to see to follow the mountain trails. The robber had not much of a start, but he was riding Jack's fleet pony, and that, in itself, meant a great deal, for there were few horses in that part of the country who could distance him.

Over the trails they rode, and, as they went, the hope of soon catching the robber grew less and less.

"I'm afraid he's escaped us all right," the marshal said, ruefully. "But we'll get him yet. I'll never let a horse thief get the best of me!"

"You seem to forget that he also took those valuable letters," Jack remarked.

"No, I'm not forgetting it," the marshal said, "but to my way of thinking that ain't half so bad a crime as taking your horse. And I'd say the same thing if he took any other horse, or one of mine. I just naturally hate a horse thief!"

"That's right!" chimed in several of the men in the posse.

There were no places, or, rather, only one or two places, along the mountain trail, where inquiries could be made as to whether or not the robber—or some night-rider—had passed. But at such lonely cabins as Jack and his friends came to they roused the inmates and put their questions.

"Seems to me I did hear a hoss gallopin' about an hour back," said one old man. "I thought maybe it was the pony express goin' through, though, so I didn't pay no attention."

"I wish it had been the pony express," murmured Jack regretfully. "If I had taken the letters on the night ride I might have gotten safely through with them."

"I don't hardly believe it," the marshal told him. "I guess those outlaws were watching the trail. They were bound to get them, and when they found you weren't going through with 'em they came in and blowed the safe."

"I suppose so," murmured Jack.