He observed that when a pedestrian going the opposite way forced them to part they came together again directly afterwards.

Without intending to watch them he never quite lost sight of the yellow scarf twisted round Katharine's head, or the light overcoat which made Rodney look fashionable among the crowd.
At the Strand he supposed that they would separate, but instead they crossed the road, and took their way down one of the narrow passages which lead through ancient courts to the river.

Among the crowd of people in the big thoroughfares Rodney seemed merely to be lending Katharine his escort, but now, when passengers were rare and the footsteps of the couple were distinctly heard in the silence, Denham could not help picturing to himself some change in their conversation.
The effect of the light and shadow, which seemed to increase their height, was to make them mysterious and significant, so that Denham had no feeling of irritation with Katharine, but rather a half-dreamy acquiescence in the course of the world.

Yes, she did very well to dream about--but Sandys had suddenly begun to talk.

He was a solitary man who had made his friends at college and always addressed them as if they were still undergraduates arguing in his room, though many months or even years had passed in some cases between the last sentence and the present one.