Chapter 11

A DISGUISE PENETRATED

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