opportunity.

The two mechanics therefore were soon at work, wheeling in the
aeroplane, as the boys trudged off down the road to the village.
Half-way there they were startled to hear the loud "honk-honk" of a
rapidly approaching auto behind them and to be hailed in an imperious
voice that shouted:

"Get off the road!"

The boys had no choice but to step nimbly aside as the car whizzed by
in a cloud of dust, but quick as had been its passing, Frank and Harry
gave a simultaneous sharp exclamation as they both recognized the face
of its occupant. Luther Barr, once clear of the grounds, had removed
his uncomfortably warm autoing mask and the two lads, as the car
vanished in a cloud of yellow dust, both cried out his name in sharp
astonishment.

"Whatever can he be doing here?" exclaimed Billy.

"I don't know; but you can depend on it he is up to no good," was
Frank's reply.

"The old fox,--I wonder if he recognized us?" cried Harry.

"If his eyes are as keen as they used to be, he did, without a
question," rejoined Frank.

The boy was right. Old Barr had recognized them, and knew them all the
more readily indeed for the reason that at that very moment his mind