A shell can be heard coming when it is passing to one side or overhead, but when it is headed straight toward you its cry is heard usually after the explosion, or is drowned out by the explosion. Common mathematics will show why. Air conditions also help. If the wind is traveling with the shell, one stands a fair chance of hitting the earth before the shell explodes. But if the wind is traveling against the shell, one hasn't much salvation.
In this case the wind was in the lads' favor. As they both heard the shell coming, they moved like lightning. It is surprising sometimes how fast one can move at a time like this.
In taking their places in the funk holes, which had been dug by the Germans when they were in possession of that piece of ground, Hal and Chester had calculated on just one thing—having time to fit themselves into the holes before shells should find them. And now that both found it necessary to make a quick fit of it, they were disgusted with their laziness in not spending enough energy and taking the chances necessary to making them big enough in the first place.
"Why didn't I?"
That was the question each lad asked himself a dozen times during the brief space of a moment they lay there half exposed and waiting for that which they feared.
It broke at last. The earth boiled, up, a mass of clods and stones, only a few yards in front of Hal. A piece of shell fragment struck his helmet a glancing blow; another buried itself in the earth only a few inches from his nose.
Hal crawled out of his funk hole and reinserted himself, making sure this time that he was below the surface. By his watch it lacked still five minutes of 11 o'clock. Almost time for all this business to stop.
At intervals for several seconds, Boche shells came screaming in, exploding hither and yon.
"Gas! Gas!" came the startling cry down the line.
Chester crawled deliberately into his gas mask, for the bursts, which he recognized on the moment as being gas shells, had been too far away to cause them any immediate alarm.