Perhaps nobody will ever know." Then they relapsed into silence for a little while.

The _Arrow_ flew fast and the motor drummed steadily in their ears.

Lannes let the aeroplane sink a little lower, and John became conscious of a new sound, akin nevertheless to the throb of the motor.

It was the concussion of the battle.

The topmost and weakest waves of air hurled off in circles by countless cannon and rifles were reaching them.