FOR PURPOSES OF OBSERVATION

Almost due west sailed the two dirigibles, their engines humming stridently. Behind them the world brightened momentarily with crimson and gold, ahead the gray night was fleeing fast. Seventeen hundred feet above the flat world passed the ships, the _F 8_ showing the way, the _9_ following a half-mile astern. The river came into sight, a pale copper flood between its shadowed banks; a sleeping town, tiny squares and angles, passed beneath. The railway caught the early sunlight, and gleamed and flashed from its polished steel. Another village, then the Rio, crossed at an angle, and then Mexico. The world below lost its neutral tint of gray and changed to shades of tan and green. The sky overhead became blue. The belly of the envelope took on a wonderful sheen of pinkish silver. The air grew warmer.

Hugh laid his “earmuffs” aside and motioned Jack to the seat. “It’s great to have the thing working right again,” he said, stretching his arms. “There’s a lot of jabbering going on this morning. The Tampico station is as chatty as you please. Wish I knew enough Spanish to tell what they’re saying. Get ’em?” Jack nodded. “The chap who’s sending down there is no dub, either. Got a good punch, he has. Hello, there’s a railroad train right under us, going south; and a bunch of villages; one every mile or two, it looks like. Might be the Main Line out of Philadelphia! Wish we were close enough to see what they’re thinking about us down there. Funny they don’t do some of that firing at us they promised.”

Jack picked up his pencil and began to write, and Hugh leaned over his shoulder and read the message as he set it down.

“Code, eh? That’s Thomas. Bet you the old boy would have given a lot to have come along with us. Here, I’ll take it up.”

Presently he was back with an answer and Jack flashed it off. Then the _9_ asked for the commander on the telephone. And so it went, the two radio boys taking turns at the bench. The morning wore away. At eight there had been coffee and sandwiches, and now, at half-past ten, more coffee was served. They had crossed the boundary between Nuevo Leon and Coahuila and were up around twenty-five hundred feet. In the southwest a heavy bank of clouds was lying, but the rest of the sky, save for a haziness along the horizon, was clear. Far below, the town of Monclova passed and low mountains showed to the south and west. Shortly after, word came from the _F 9_ that she was having trouble with her starboard engine and would have to slow down. In consequence, the _Fate_ shut off her port engine and for more than a half-hour the two ships kept to a twenty-six mile speed.

It was after eleven-thirty when the airplanes were sighted. They appeared first as infinitesimal specks far to the east, specks that swam vaguely in and out of vision, but rapidly they took on form and substance, and at noon were only a few miles astern, five gray biplanes traveling in battle formation like a flight of giant geese. Soon Hugh picked up the first telephone call from the leader and presently the planes, flying several hundred feet above the dirigibles, passed westward. When they had gained a half-mile lead they slowed to the sixty-mile speed that the balloons had again returned to, and in such fashion, strung out over a length of more than a mile of air space, the expedition came to the eastern edge of the desert land.

Captain Taylor, in temporary command of the _F 8_, came back into the radio cockpit. He was a tall, sallow-skinned man of thirty-one or two, with sharp brown eyes and a veritable beak of a nose. He and a Lieutenant Sandborn were alone attending to the navigating, for as the _Fate_ was expected to bring back one of the imprisoned officers, it had been thought best to reduce the crew by one. Later the boys discovered that the _F 9_ held but five men, including a single radio operator, and concluded that their inclusion in the personnel of the _Fate_ was in the nature of a reward. The captain asked about the location of the Perdero jail in relation to the barracks and whether it could be readily picked out. The boys were doubtful as to the latter.

“It’s a small building,” explained Hugh, “about a hundred yards from the general’s headquarters and about fifty yards from the corral. It’s nowhere near the barracks, though.”

“Well, I’ll get you to point it out when we get in sight,” said Captain Taylor. “What’s your idea of this fellow Roza, anyhow? Think he’ll be there when we arrive, Mr. Clode? Or will he have moved out?”

“I don’t know, sir. Seems to me that when he found we’d got away with the dirigible he’d decide to beat it before we came back. But those Mexicans are a queer lot, Captain. You can’t tell how they’ll jump. Seems like their brains worked differently from ours. Look at the crazy things they do!”

“They’re like children, I think,” said Jack. “I don’t believe they mean to be――be bad. They’re ignorant, that’s their trouble. They believe what they’re told and never stop to reason anything out for themselves. I guess it’s too much trouble!”

“That’s rather my idea of them,” agreed the captain. “At least, of the run of them, the working class and the more ignorant. Of course, the intelligent Mexicans are different. At least, they know what they’re doing. This fellow Roza’s no ignoramus, I take it. They say he’s well educated, a graduate of a military college and saw service in the World War. Blessed if I can get his point of view, though. He must know he’s mixing himself an awful mess of trouble when he acts like he’s been acting!”

“Maybe,” said Jack, “he relies on being able to get out of the way before the trouble starts.”

“I dare say. If so we’ll find him gone when we get there. The prisoners, too, likely. If he is, all we can do is beat it home again. Looking for him in this country would be like――like looking for a needle in a haymow. See anything familiar, Mr. Clode?”

Hugh looked down over the desert now but a few hundred feet beneath and shook his head. “No, sir. How far from Perdero are we?”

“If we’ve got it located right on the map, about forty miles. Suppose you come up for’ard in about ten minutes and take the glasses. We’d ought to be sighting something by that time. My word, this is a lonely stretch of country, isn’t it?”

“Do you really believe that we’ll go back without having a search for them if they’re not there?” asked Jack anxiously when the captain had gone forward again.

“Sounded as if he meant to,” answered Hugh. “I can’t see it, though. Even if Roza hiked off the minute we left there yesterday he couldn’t be far off. Twenty-four hours won’t take you a great distance in this country, I’ll bet. And where is there he can hide, anyhow?”

“Well, there are mountains down that way.”

“Yes, but they must be a good long ways. They don’t even show up now. I sort of half expect to find things about as we left them, Jack. It sounds crazy, I know, but I don’t believe that Tito Roza really expects us. Besides, you know what a way they have of putting things off. They’ve got this ‘_mañana_’ bug, old son, and you can’t cure ’em!”

“I hope you’re right. I’d surely hate to go back without Mr. Weeks, Mr. Jordan and the others.” After a moment’s silence Jack continued. “I wonder if you remember something you said that day you showed me around this boat, Hugh.”

“What was it?”

“You said that you had a hunch that some day you’d be in command of her. Sort of funny, the way it turned out.”

“Y-yes, wasn’t it? Know something, Jack? Well, I’m going to get transferred to the Engineering Branch if I can work it. This pounding a key is all right, but――but I want to get in the real game! That way, maybe some day I’ll get a command, you see.”

“Wish I could, too,” mused Jack. “I believe I’ll try for the Balloon Corps. Think I could make it? Maybe Admiral Thomas would sort of help me. He seemed mighty nice and friendly last night.”

Further speculation was interrupted by the tube and Jack put his ear to it. “Captain Taylor wants you for’ard, Hugh. He thinks he’s spotted something. And here’s _684_ on the ’phone. Take this along, will you? ‘Destination sighted. Will fall back and await your orders. Guernsey.’ I’ve O. K.’d it. Here you are.”

Shortly after one o’clock Perdero lay before them some five miles distant across the windswept desert. Through glasses a flash of color showed where the flag of the Independent State of Coahuila still fluttered above the mud-walled headquarters building. Slowed down to fifteen miles an hour, with the airplanes hovering overhead, the _F 8_ moved on toward the sunlit village. Behind her, vast and inexorable, came the sister ship.