up to the desk, and paid twopence for his glass of milk
and his bun. Soon he disappeared through the shop, whilst she still
found herself hopelessly bewildered, with a number of snap-shot
photographs before her, still staring at a long piece of string,
smothered from end to end in a series of knots, as bewildering, as
irritating, as puzzling as the man who had lately sat in the corner.

CHAPTER IV

THE ROBBERY IN PHILLIMORE TERRACE

Whether Miss Polly Burton really did expect to see the man in the corner
that Saturday afternoon, 'twere difficult to say; certain it is that
when she found her way to the table close by the window and realized
that he was not there, she felt conscious of an overwhelming sense of
disappointment. And yet during the whole of the week she had, with more
pride than wisdom, avoided this particular A.B.C. shop.

"I thought you would not keep away very long," said a quiet voice close
to her ear.

She nearly lost her balance--where in the world had he come from? She
certainly had not heard the slightest sound, and yet there he sat, in
the corner, like a veritable Jack-in-the-box, his mild blue eyes staring
apologetically at her, his nervous fingers toying with the inevitable
bit of string.

The waitress brought him his glass of milk and a cheese-cake. He ate it
in silence, while his piece of string lay idly beside him on the table.
When he had finished he fumbled in his capacious pockets, and drew out
the inevitable pocket-book.

Placing a small photograph before the girl, he said quietly:

"That is the back of the houses in Phillimore Terrace, which overlook
Adam and Eve Mews."

She looked at the photograph, then at him, with a kindly look of
indulgent expectancy.

"You will notice that the row of back gardens have each an exit into the
mews. These mews are built in the shape of a capital F. The photograph
is taken looking straight down the short horizontal line, which ends, as
you see, in a _cul-de-sac_. The bottom of the vertical line turns into
Phillimore Terrace, and the end of the upper long horizontal line into
High Street, Kensington. Now, on that particular night, or rather early
morning, of January 15th, Constable D 21, having turned into the mews
from Phillimore Terrace, stood for a moment at the angle formed by the
long vertical artery of the mews and the short horizontal one which, as
I observed before, looks on to the back gardens of the Terrace houses,
and ends in