"All of a sudden I was struck with a brilliant inspiration, and I let the old Colonel have it for what it was worth.
"As it happened the old man thought a mighty lot of it—such a lot, in fact, that by one o'clock that day he started to imagine the inspiration had come from his own fertile brain. He liked to think that it was his, and, Lord bless 'im, I don't grudge him the glory.
"After laying our heads together, the Colonel went back to the artillery lines and spent three hours talking to the Battery Major, and I looted a dozen three-pounder rockets of var-i-ous colours out of the stores. In the afternoon the Colonel called all his officers together, and kept the blighted motorcycle dispatch riders busy buzzing up and down the line with messages, till late in the evening.
"'I have called you gentlemen together,' he says to his officer, 'in order to ask you to corporate with me. I shall fire some rockets from the slag heap to-night about ten o'clock. On the first of these signals the Germans will open a very heavy cannonade on our trenches. I'll trouble you to have your men all in the dug-outs, and under cover at a quarter to ten!'
"That night, soon after the Colonel, Tommy and I started off for the slag heap in the dark, taking with us a bundle of rockets. My idea was at last going to be tested—what do you think it was, Sir?"
I discreetly pretended my utter inability to guess.
"Why, nothing more or less than to hoist these German blokes with their own petard, so to speak. We were going to fool them by giving them signals in their own code. Well, after stumbling and groping about for half an hour," McNab continued, "we arrived at the spot near where we had overlooked the spy.
"'I think this is the ledge from which I fell,' Tommy whispered as we crawled on. The next instant the Colonel disappeared, and the little procession came to an abrupt standstill. A crashing noise was heard as the old man with a quarter of a ton of slag went tobogganing down the stone-shod slope.
"'This is the spot,' Tommy said tersely. And up to us came hoarse whispered curses as our ole man tongue-lashed us for a full minute in gross and detail.
"'Lie quite still, Colonel,' I whispered, 'the Hun swine-dogs may send up a flare if they hear us.'