"I thought that the aim of all philosophy was to check every impulse," said Ella.

"So it is; that's why women do not make good philosophers," said her husband.

"Or, for that matter, good mothers of philosophers," said Herbert.

"That's rather a hard saying, isn't it?" said the other man.

"No," said his wife; "it's as transparent as air."

"London air in November?" suggested her husband.

"He means that there's no such thing."

"As air in London in November? I'm with him there."