"Megaphone!" cried Adams, jumping up.
The officers rushed into the gun-pit. The men who had been working outside came racing in. In a few moments another order was shouted through a megaphone by the man in the telephone room--a shell-proof cave hard by. "Target M--one round battery fire."
Captain Adams took up a map of the German trenches, and with a rapidity that amazed Burton, angles and fuses were adjusted, and in a few seconds a shell went whistling and screaming towards its invisible target miles away. Cay had gone to the wireless instrument in the corner, and sat with the receiving telephones at his ears.
"Range right; shell dropped quarter-mile to the left," he called presently.
New adjustments were made; the gun fired again.
"How's that?" asked Adams.
It seemed only a few seconds before Cay, repeating the message he had received from the invisible aeroplane scouting aloft, replied: "Got him!" A moment later he added: "New battery----" He broke off: the burring of the instrument had ceased. He tried to get into communication again, but failed. "Ask O.P. if they've seen the 'plane," he called to the telephonist. Presently came the answer: "Went out of sight behind a wooded hill. Afraid a Hun 'Archie' has brought it down."
Meanwhile the order "Break off" had been received. The immediate task of the battery was accomplished.
II
The officers returned to their dug-out.