He was hanging over the balustrade at the curve of the stairs.

The familiar ease with which he said, “Now, Nellie,” and especially the spontaneity of Nellie’s instant response, put new thoughts into the mind of Mrs Machin.  But she neither pricked up her ears, nor started back, nor accomplished any of the acrobatic feats which an ordinary mother of a wealthy son would have performed under similar circumstances.  Her ears did not even tremble.  And she just said: 

“I like this balustrade knob being of black china.”

“Every knob in the house is of black china,” said Denry.  “Never shows dirt.  But if you should take it into your head to clean it, you can do it with a damp cloth in a second.”

Nellie now stood beside him.  Nellie had grown up since the Llandudno episode.  She did not blush at a glance.  When spoken to suddenly she could answer without torture to herself.  She could, in fact, maintain a conversation without breaking down for a much longer time than, a few years ago, she had been able to skip without breaking down.  She no longer imagined that all the people in the street were staring at her, anxious to find faults in her appearance.  She had temporarily ruined the lives of several amiable and fairly innocent young men by refusing to marry them. (For she was pretty, and her father cut a figure in the town, though her mother did not.) And yet, despite the immense accumulation of her experiences and the weight of her varied knowledge of human nature, there was something very girlish and timidly roguish about her as she stood on the stairs near Denry, waiting for the elder generation to follow.  The old Nellie still lived in her.

The party passed to the first floor.

And the first floor exceeded the ground floor in marvels.  In each bedroom two aluminium taps poured hot and cold water respectively into a marble basin, and below the marble basin was a sink.  No porterage of water anywhere in the house.  The water came to you, and every room consumed its own slops.  The bedsteads were of black enamelled iron and very light.  The floors were covered with linoleum, with a few rugs that could be shaken with one hand.  The walls were painted with grey enamel.  Mrs Cotterill, with her all-seeing eye, observed a detail that Mrs Machin had missed.  There were no sharp corners anywhere.  Every corner, every angle between wall and floor or wall and wall, was rounded, to facilitate cleaning.  And every wall, floor, ceiling, and fixture could be washed, and all the furniture was enamelled and could be wiped with a cloth in a moment instead of having to be polished with three cloths and many odours in a day and a half.  The bath-room was absolutely waterproof; you could spray it with a hose, and by means of a gas apparatus you could produce an endless supply of hot water independent of the general supply.  Denry was apparently familiar with each detail of Mr Wilbraham’s manifold contrivances, and he explained them with an enormous gusto.