"Where away? I can't see him."
"Right behind us. He must have over-shot the mark also, and he's coming back on our trail from Brussels."
The next instant, Dastral did a rapid swerve, and a steep nose-dive, in accordance with the pre-arranged code made before starting.
This was quite sufficient, for the strangers had been stalling their machines, and circling around, waiting for the signal. Now they opened out their engines and came on at top speed to meet their leader.
As they came up Jock could see the observers waving their hands in recognition. Yes, they were all here. The first part of the business was over. They had all come safely through and gained the rendezvous.
"Now we must get to work, for there's trouble brewing somewhere for us, and the sooner we get through the affair the better," shouted the pilot through the speaking tube.
As the machines came up, they wheeled smartly round, and each took up its appointed place in the formation. To an observer down below it must have appeared that they were great birds wheeling about to order, just like a platoon of infantry on parade.
"Prepare for action," was the next signal given, as they sped off, led by Dastral.
"Braine l'Alleud next," called Dastral.
"Yes, a little further to the right, just below the dip in the hill. We should see the Zeppelin sheds shortly," responded Jock, who was ready for the query, and had one finger already on the waterproof map.