the boys, in spite of their broken slumbers, all turned out promptly at four o'clock the next morning. they found this hour the pleasantest of the day in this hot and dry region. the late moon was just disappearing, and over the plains swept a breeze that hinted of snow on some mountain peak not far away. not a sound broke the stillness but the occasional cry of a skulking coyote.
"hear it, elmer," said alan, as the boys got busy in the baggage car. "you want to look out for those fellows."
"i ain't feared o' no cutes and i ain't feared of no injun," solemnly answered elmer, "jist so dem rattlers gives me de go-by. dat's all i ast."
buck's big wagon had arrived and was backed up to the car and now, by the light of a lantern hanging above the door, the work of loading began.
with their improved gas bag the boys had figured on a record flight without renewing the gas supply. they had hoped to be able to stay at least seventy-two hours in the air. but during a large part of this time they expected to drift without the engines, for they could not carry enough gasoline to last for more than twenty-four hours of engine work. by their new calculations they had more than enough gasoline, and according to ned it seemed probable that the decreased air pressure on the bag might extend the period of flight another twenty-four hours, or to four days.
after that all would depend on the liquid hydrogen. the remarkable qualities of this unique product were to be tested for the first time in the history of ballooning. when the gas in the bag had diminished by leakage through the valves and elsewhere so that it was no longer sufficient to carry the car, the liquid hydrogen was to be turned into gas which was to take the place of that lost. ned had left washington with sixteen cubic feet of the liquid in eight delicate dewar bulbs, or casks. he figured that one-quarter of it would be lost by evaporation, leaving twelve cubic feet. this seems a small supply until one understands that the hydrogen increases in volume 880 times as it returns into gas from the liquid form. the twelve cubic feet of liquid, therefore, would give them a little over ten thousand cubic feet of new gas. and this, with the loss of ballast and provisions in three or four days, ned calculated, would give the balloon a new life of a day or so.
therefore, the secret plan was a direct journey to elmer's camp, a flight of eighty-five miles, which would bring the cibola near to the foot of the mountains of mystery. after this camp had been located and more gasoline taken aboard the boys were to head their craft toward the tunit chas mountains. what would follow they could not foresee. with good luck they might be able to hover birdlike over the peaks, canyons and plateaus for five days. with bad luck they might have to come down sooner or fall. then, if the cibola failed them, they would have to find their way to the treasure temple and the ruined palace on foot in a rugged wilderness, infested with unfriendly indians and reptiles, or struggle back, in some manner, if they could, to elmer's relief station, and thus to civilization.
should the worst happen and the balloon fail them, the boys might be lost in a desolate region that is even now uncharted by the government. the only resources they would have would be the cibola equipment and their own ability to take care of themselves. in any event, the knowledge that elmer and buck were in camp ready to succor them meant a good deal. and that was why the loading of the overland outfit had so much interest for the boys.
of tins of provisions there were many: condensed foods—german erbswurst, or army rations of ground peas and meat; dried potatoes; eggs in powdered form; preserved and salt meats; hard tack; tea and coffee; flour; and evaporated fruits. the water was already arranged for and the wagon containing the casks was at buck's adobe house.
on the floor of the wagon, packed in bunch grass, were the precious gasoline casks. on top of all came the silk waterproof tent and the camp equipage. stowed under the seat was the box containing spare flags, a heliograph, part of a wireless telephone outfit (the other part was to be carried in the balloon) and compass. two magazine rifles and ammunition were included in the outfit, and elmer donned for the first time in his life a belt and holster to carry one of the magazine revolvers that ned had bought on the day when he first told alan what he had undertaken to do.
by the time this work was done it was day. then came breakfast, which elmer insisted on preparing. he even demanded that he be given time to make hot biscuits. these, with thick slices of broiled ham, the last of their oranges, and hot fragrant coffee constituted the last meal on the placida.
as the meal came to an end the clump, clump of horses' feet in the sand announced that buck had arrived and that it was time for breaking the "special car" camp. alan and elmer hastened to clean up the little kitchen that had given the boys so many savory meals and to pack up the remaining provisions, and ned jumped off the car to see buck.
to the lad's surprise he found gus, the tramp, just as dirty and just as cheerful as ever, proudly mounted on one of the newly arrived horses. buck noticed the surprise in ned's face and explained:
"the helper i thought i could get fell down on me. my boarder's goin' with us. i guess he'll do."
"you understand you don't know where you're going," said ned, approaching gus as he rolled off his horse, "nor when you're coming back?"
"i knows dat we ride and dat dere's chuck a-plenty," smiled gus, "and whichever way it is," he added lowering his voice and chuckling, "can't be no worse dan buck's place—fur me."
"do you want to go?"
"well, i ain't a settin' up nights a longin' to, but to oblige a friend, mr. buck, i allowed meself to be persuaded."
"well, we'll see," said ned.
ned rather wanted to watch this young man. something suggested that the tramp was too quick witted to be made a party to their plans. ned didn't exactly know what harm the stranger could do them, but he decided to talk it over with alan. while buck was hitching up the horses ned turned to go into the car.
they were loading from the far side opposite the hydrogen cask and as ned passed the corner of the car he almost ran into the station agent. the agent, who was also the telegraph operator, had a telegram for ned, which the boy took eagerly. ned had sent a message to major honeywell, telling of their safe arrival, and did not doubt that this was some important afterthought of the major's. the address ran: "mr. ned napier, private car placida, clarkeville, new mexico." tearing open the envelope ned read:
"just learned kansas city comet has story mysterious trip for government starting clarkeville. real object not known. look out not followed.
"baldwin honeywell."
with three jumps ned was in the car and had pull alan into the drawing room portion. the telegram was read again and the two boys looked at each other in astonishment.
"how could they?" began alan.
"no matter how," answered ned, almost out of breath. "they did and that's enough. now i know!"
"know what?"
ned pushed his chum to the side of the car and pointed outside where buck and his helper were at work.
"look at him," he exclaimed.
"at buck?"
"no. at the tramp who won't wash his face, who has a gentleman's underclothes and who is so anxious to work for us!"
"well, i see him. but—"
"haven't you ever seen those sharp eyes before?"
"you don't mean—?"
"i do. if that isn't bob russell, the comet reporter, i'm a goat."
