The next thing was that a window opened in the high wall-face of the house and an immense stream of liquid descended full on the man’s head.  Susan Foley was at the window, but only the nozzle of the extinguisher could be seen.  The man tried to climb over the railings; he did not succeed; they had been especially designed to prevent such feats.  He ran down the steps.  The shower faithfully followed him.  In no corner of his hiding did the bountiful spray neglect him.  As soon as one supply of liquid slackened another commenced.  Sometimes there were two at once.  The man ran up the steps again and made another effort to reach the safety of the street.  Audrey could restrain herself no more.  She came, palpitating with joyous vitality, towards the area gate with the innocent mien of a passer-by.

“Whatever is the matter?” she exclaimed, stopping as if thunderstruck.  But in the gloom her eyes were dancing fires.  She was elated as she had never been.

The man only coughed.

“You oughtn’t to take shower-baths like this in the street,” she said, veiling the laughter in her voice.  “It’s not allowed.  But I suppose you’re doing it for a bet or something.”

The downpour ceased.

“Here, miss,” said he, between coughs, “unlock this gate for me.  Here’s the key.”

“I shall do no such thing,” Audrey replied.  “I believe you’re a burglar.  I shall fetch a policeman.”

And she turned back.

In the house, Miss Ingate was coming slowly down the stairs, a fire-extinguisher in her arms, like a red baby.  She had a sardonic smile, but there was diffidence in it, which showed, perhaps, that it was directed within.

“I’ve saved one,” she said, pointing to an extinguisher, “in case there should be a fire in the night.”

A little later Susan Foley appeared at the door of the living-room.

“Nine o’clock,” she announced calmly.  “Supper’s ready.  We shan’t wait for Jane.”

When Jane Foley arrived, a reconnaissance proved that the martyrised detective had contrived to get away.

CHAPTER XXIII

THE BLUE CITY

In the following month, on a Saturday afternoon, Audrey, Miss Ingate, and Jane Foley were seated at an open-air cafe in the Blue City.

The Blue City, now no more, was, as may be remembered, Birmingham’s reply to the White City of London, and the imitative White City of Manchester.  Birmingham, in that year, was not imitative, and, with its chemical knowledge, it had discovered that certain shades of blue would resist the effects of smoke far more successfully than any shade of white.  And experience even showed that these shades of blue were improved, made more delicate and romantic, by smoke.  The total impression of the show—­which it need hardly be said was situated in the polite Edgbaston district—­was ethereal, especially when its minarets and towers, all in accordance with the taste of the period, were beheld from a distance.  Nor was the exhibition entirely devoted to pleasure.  It had a moral object, and that object was to demonstrate the progress of civilisation in our islands.  Its official title, indeed, was “The National Progress Exhibition,” but the citizens of Birmingham and the vicinity never called it anything but the Blue City.