"Enemy column on the march!"
"The deuce it is?" queries the pilot.
"Yes, ammunition column, I think, but we'll soon find out."
Then the tapping begins again, and the message is flung across the battle-ground and is picked up. With a swift mental calculation the observer has reckoned up when the head of the column will reach a certain point in the road, where a bridge carries the road over a tributary of the Somme.
"Swis-s-s-h! Boom-m-m-m!" comes the first heavy fifteen-inch shell.
It is a little short and another message on the keys is necessary.
This time the shell falls plump right into the middle of the column, for so accurately are the guns trained, that, though they cannot see the object they are firing at, if the message sent only gives the exact position on the map, a direct hit is soon gained.
The consternation of the Germans can be better imagined than described. Thinking themselves in comparative security so far behind the lines, a huge shell without the slightest warning explodes near by, and the next lands clean in the middle of the column.
The object hit was a motor lorry conveying ammunition up to the guns. The first explosion is followed by another, more terrific than the first, for a couple of hundred shells are exploded, and when the smoke and dust have cleared away the observer and his pilot look down, and there is a huge gap in the column, for two of the lorries are blazing, several have been overturned, and one has disappeared entirely from view.
Not only so but the road is blocked for the next six or seven hours for all traffic, and not only will guns go short of ammunition but more than one battalion of the German army will go short of food for the next twenty-four hours.