"An aviatik, coming our way," he called.
"Won't catch us," responded Burton with a smile.
"Stay and fight it?"
"It's tempting, but we mustn't. It won't do to run risks when our job's to collect information."
Hunter acquiesced with a sigh. Burton shifted his course a point or two to the west, so as to run nearly parallel with the enemy's aeroplane.
A moment or two later he gave a start of alarm.
"What's the matter?" asked Hunter.
"Afraid there's a leak. The petrol gauge is falling faster than it ought. They must have knocked a hole in the tank. See if you can find it."
Hunter twisted in his seat, bent over, and began to examine the tank.
"Can't find any leak," he said presently. "If there's one, it's out of reach. How's the gauge?"