"Where?" he asked.
"Begin as I told you and sweep your eyes around the circle."
"Ah, I see it now! Or maybe it's just a mote in the dancing sunbeams."
"Oh no, it's not. Watch it grow. It's an aeroplane, and I'd wager everything against next to nothing that it's the one that left a little while ago. Whatever it went to do it's done."
"Upon my soul, I think you're right. It is growing as you say. Now the dot becomes a black spot as big as an egg, now it grows to the size of your hand, and now the shape of a flying machine, coming at terrific speed, emerges. The whole process of departure is reversed."
"And it's making straight for that overhanging group," said Wharton.
John watched the big birds of prey await the messenger, and again he longed intently for Lannes' powerful glasses. The returning machine was received by the others which formed a circle about it, and for some minutes they hung there in close company.
His nerves began to quiver again with excitement. He was sure that it was a menace. The small aeroplane would not have gone away on a mission without some excellent reason. Sure of his leafy covert he stood up, and watched the group which now circled almost exactly over their heads. Carstairs and Wharton stood beside him, and again they turned to him as the leader, now that it was an affair of the air.
"What do you make of it?" asked Carstairs, anxiously.
"It means harm, some new method of attack," said John, "but for the life of me I can't guess what it is."