In his hand he still held the revolver.

He pressed it upwards against the thing that was smothering him, and pulled the trigger.

Again he pulled it, and again, for it was a self-cocking weapon, and even there deep down in the water he heard the thud of the explosion of the damp-proof copper cartridges.

His lungs were bursting, his senses reeled, only enough of them remained to tell him that he was free of that strangling grip and floating upwards.

His head rose above the surface, and through the mouth of his mask he drew in the sweet air with quick gasps.