A French engineer officer joined us. He told us General Lefebvre, the French General in command of that section of the Salient, had issued most elaborate written instructions for the joint explosion of the two mines. The French mine, he said, had been ready for two or three days, its charge lying at the end of a tunnel but two metres from the German trench.
The hour for the discharge of the French mine came, but no sound or shock of explosion came with it. The hands of the Allied watches, carefully synchronised, crept round to 7·50, then to 7·55.
Just before eight o'clock a huge bang was heard by the British sapper who was waiting in his tunnel, ready to fire his mine.
"At last," he murmured. "Now I must count off the five minutes to the second."
A squadron of the Queen's Bays was ready to rush into the enemy's trench. Ten of them, the forward storming party, were waiting in a saphead.
One, two, three, four, and at last, five.
Boom!
The whole earth seemed thrown skyward. The shock was terrific. Nearly one thousand pounds of blasting powder had tossed fifty yards of German trench, not two hundred feet in front of our line, high in air.
The great smash came as a complete surprise to the Huns, but, alas! an equal surprise to French and British.