They could easily see the two who were in the Taube, the pilot paying attention to his part of the business, while his companion leaned eagerly forward, intently watching so as to hurl the bomb at the right second.
Frank judged rightly that the man would make allowances for the speed of the motor van along the road, when he sent the explosive. That was where their real chance to outwit the enemy lay.
Keenly he watched this second man, forgetting about the pilot, who really had little to do with the hurling of the bomb.
“There, he’s raising his hand, Frank!” cried Pudge.
“And I can see what he’s gripping, too!” added Billy vociferously.
“Keep still!” ordered Frank, who did not wish them to be making any sort of racket while the crisis was so close at hand, since it might interfere with what he meant to do, and that was of vital importance to them all.
Frank could judge for himself about when the man was apt to throw his deadly missile. Their own speed was only a certain per cent slower than that of the hostile aëroplane above.
Just when he discerned a movement of the man’s whole body and knew he was in the act of speeding the explosive, Frank gripped the arm of the waiting chauffeur.
Instantly the expectant driver shut off all power and applied the brake. It was just as though he had suddenly found himself about to plunge through the open draw of a bridge into a deep river.
Even as the big clumsy van came to a halt in the road there was a fearful crash not thirty feet ahead of them, accompanied by a puff of smoke.