“That is odd,” said the little man, arching his black eyebrows.  “I live, myself, in Himylaya Mansions, round the corner.  Perhaps you might care to come with me; I can go to my rooms and sort out these queer Welkin documents, while you run round and get your friend the detective.”

“You are very good,” said Angus politely.  “Well, the sooner we act the better.”

Both men, with a queer kind of impromptu fairness, took the same sort of formal farewell of the lady, and both jumped into the brisk little car.  As Smythe took the handles and they turned the great corner of the street, Angus was amused to see a gigantesque poster of “Smythe’s Silent Service,” with a picture of a huge headless iron doll, carrying a saucepan with the legend, “A Cook Who is Never Cross.”

“I use them in my own flat,” said the little black-bearded man, laughing, “partly for advertisements, and partly for real convenience.  Honestly, and all above board, those big clockwork dolls of mine do bring your coals or claret or a timetable quicker than any live servants I’ve ever known, if you know which knob to press.  But I’ll never deny, between ourselves, that such servants have their disadvantages, too.”

“Indeed?” said Angus; “is there something they can’t do?”

“Yes,” replied Smythe coolly; “they can’t tell me who left those threatening letters at my flat.”

The man’s motor was small and swift like himself; in fact, like his domestic service, it was of his own invention.  If he was an advertising quack, he was one who believed in his own wares.  The sense of something tiny and flying was accentuated as they swept up long white curves of road in the dead but open daylight of evening.  Soon the white curves came sharper and dizzier; they were upon ascending spirals, as they say in the modern religions.  For, indeed, they were cresting a corner of London which is almost as precipitous as Edinburgh, if not quite so picturesque.  Terrace rose above terrace, and the special tower of flats they sought, rose above them all to almost Egyptian height, gilt by the level sunset.  The change, as they turned the corner and entered the crescent known as Himylaya Mansions, was as abrupt as the opening of a window; for they found that pile of flats sitting above London as above a green sea of slate.  Opposite to the mansions, on the other side of the gravel crescent, was a bushy enclosure more like a steep hedge or dyke than a garden, and some way below that ran a strip of artificial water, a sort of canal, like the moat of that embowered fortress.  As the car swept round the crescent it passed, at one corner, the stray stall of a man selling chestnuts; and right away at the other end of the curve, Angus could see a dim blue policeman walking slowly.  These were the only human shapes in that high suburban solitude; but he had an irrational sense that they expressed the speechless poetry of London.  He felt as if they were figures in a story.