blackout engine

There was a fascination in returning stride by stride to the rattle and roar of the metal tyres upon London's stones. Denis felt it through the depths of his blank misery and impotent rage; he only wondered that the noise had never struck him in the morning. Now he picked it up plain at Hendon, and it reminded him of its miniature--the first far sound of Ballarat--as it seemed to rise with each ringing step he took. His body was bathed in perspiration; never had he walked so many miles at such a rate. But a vague object had developed on the way. By half-past nine he was in London's throat; and now he might have been walking on cotton-wool.