Jack was wondering just how his chum would act in order to bring about this separation. Hence he was not greatly surprised when Tom called out aloud, so that he could make his voice heard above the incessant whirr of motors added to the buzz of many propellers that filled the air with noise:
"Jack, something seems to be wrong with our engine."
"You don't say!" ejaculated Jack, accompanying the remark with a wide grin; for he suspected that this was only the ruse he had been anticipating.
"I don't seem to be able to get along as smoothly as I did before," continued the pilot.
"Why, it's a fact that we are letting the others outrun us some, Tom. Wouldn't it be just too bad if they went off and left us in the lurch?"
"No joke about it, Jack. Something is really going wrong, and I imagine I'm getting a poor supply of gas. Take a look at the tank, will you, and see if it's all right!"
At that Jack ceased to chuckle. He realized from what the other said that he meant it seriously. Accordingly Jack bestirred himself to carry out the instructions of the pilot, which he was best able to do from his position aft.
A brief interval of silence followed, save for the constant hum of the machinery and the whirling propellers. Then Jack uttered a loud cry that expressed both astonishment and alarm.
"Tom, you guessed it!" he called. "The blooming tank is empty, and we're feeding on the scant reserve in the smaller tank!"
"Try to find out if a bullet cut a hole in the tank, and let our juice run out!" Tom now ordered.