His suspicions were speedily confirmed.  There was a jagged hole in the underbody of the balloon, from which gas was rushing.  Jack’s face grew grave.  The situation was dangerous.

He knew, as does every balloonist, that out-rushing gas can make an electric spark in the atmosphere which, in turn, ignites the gas itself, sometimes with fatal results.  Experts in aeronautics attribute the disasters befalling the long series of Zeppelins, the giant German dirigibles, to this cause.

“Tom, we must go down.  Drop at once,” he said.  “That old fellow succeeded in blowing a hole in us all right.”

The pumps were set to work and the Wondership fell rapidly.  They dropped in a field by the roadside, landing on the running wheels as lightly as a feather, thanks to the shock absorbers, similar to those of an automobile, with which the Wondership was equipped.

“Now for the repair kit,” said Jack, rummaging a locker.

He soon had balloon silk, big shears, a quick-drying gum solution and a pot of gasproof varnish, ready for the job of patching up the hole.  But first they had to empty the big bag of gas.  This was speedily done, for already enough had escaped to wrinkle the bag like a walnut, with hollows and creases.

Jack cut out a patch of balloon silk large enough to fit the hole and spread it with the adhesive gum solution.  This he placed inside the hole, spreading it out so that when pressure was applied it would be pressed firmly against the aperture.  Then he coated the patch with the gasproof varnish, and both boys sat down to give the job time to “set.”

Their eyes turned idly to the high-road.  It was about noon and there was a heavy sort of silence in the air.  Far on the horizon they could make out great billowy masses of white cloud.  Piled and castellated against the sky they assumed all kinds of odd shapes.

“Thunder heads,” said Jack.  “We shall have a storm before to-night.”

“It’s sultry enough for anything,” said Tom, taking off his cap and mopping his forehead.  “I’d hate to be walking in this weather like that fellow yonder.”

A man had come into sight, plodding along with bent head and eyes on the ground as if he was very tired.  The gray dust of the road coated him from head to foot.  He walked with a kind of dragging gait.

Over his shoulder he carried some sort of a bundle on a stick.  His hat was a broad sombrero, like a cowboy’s.  It was a kind of headgear seldom seen in the east and attracted the boys’ attention.  Round the man’s neck was a red handkerchief, the only spot of color on his dust-covered person.  He had a great yellow beard and rather long, unkempt hair.

“Tramp,” hazarded Tom.

Jack shook his head.

“Doesn’t look like that to me somehow,” he said.  “I rather think——­”

Round the corner whizzed a big red automobile.  It was coming fast.  The driver, a young man, had his head turned and was talking to three companions who sat in the tonneau.  He did not see the dusty traveler in the road ahead.