ng the journey, his mind being fully occupied with the latest
development of a mystery, the solution of which still evaded him.

The route through London to Scotland Yard carried him through Cavendish
Place, where the nursing home was situated in which Odette Rider lay. He
stopped the car to make inquiries, and found that the girl had recovered
from the frenzy of grief into which the terrible discovery of the morning
had thrown her, and had fallen into a quiet sleep.

"That's good news, anyway," he said, rejoining his companion. "I was half
beside myself with anxiety."

"You take a tremendous interest in Miss Rider, don't you?" asked
Whiteside dryly.

Tarling brindled, then laughed.

"Oh, yes, I take an interest," he admitted, "but it is very natural."

"Why natural?" asked Whiteside.

"Because," replied Tarling deliberately, "Miss Rider is going to be my
wife."

"Oh!" said Whiteside in blank amazement, and had nothing more to say.

The warrant for Milburgh's arrest was waiting for them, and placed in the
hands of Whiteside for execution.

"We'll give him no time," said the officer. "I'm afraid he's had a little
too much grace, and we shall be very lucky if we find him at home."

As he had suspected, the house in Camden Town was empty, and the woman
who came daily to do the cleaning of the house was waiting patiently by
the iron gate. Mr. Milburgh, she told them, usually admitted her at
half-past eight. Even if he was "in the country" he was back at the house
before her arrival.

Whiteside fitted a skeleton key into the lock of the gate, opened it (the
charwoman protesting in the interests of her employer) and went up the
flagged path. The door of the cottage was a more difficult proposition,
being fitted with a patent lock. Tarling did not stand on ceremony, but
smashed one of the windows, and grinned as he did so.

"Listen to that?"

The shrill tinkle of a bell came to their ears.

"Burglar alarm," said Tarling laconically, and pushed back the catch,
threw up the window, and stepped into the little room where he had
interviewed Mr. Milburgh.

The house was empty. They went from room to room, searching the bureaux
and cupboards. In one of these Tarling made a discovery. It was no more
than a few glittering specks which he swept from a shelf into the palm of
his hand.

"If that isn't thermite, I'm a Dutchman," he said. "At any rate, we'll be
able to convict Mr. Milburgh of arson if we can't get him