From above the gunwale of a boat stowed amidships on the Ponto a feeble light glimmered.
"Help—German raider," it signalled.
"You read it?" enquired the sailor hurriedly, as if to confirm the evidence of his own eyes.
"Yes," replied Wilmshurst, and repeated the signal.
Without another word the Zungeru's officer turned and raced to the bridge. In a few moments the signal was passed on to the Tompion by means of a flashlamp, the rays of which were invisible save from the direction of the receiver.
"Very good," was the cruiser's reply. "Carry on."
A little later the general order was flashed in to the convoy. "Increase speed to seventeen knots."
The instructions were promptly carried out as far as the transports were concerned, but from the Ponto came a signal: "Am doing my maximum speed. Must drop astern if speed of convoy is not reduced."
"The blighter has got hold of the code all right," remarked Laxdale. "We'll wait and see the fun. Wonder why we are whacking up speed?"
"The cruiser wants to get the transports out of harm's way, I should imagine," replied Wilmshurst. "By Jove, it's rummy how news spreads. The whole mess is coming on deck."