his furry black friend somewhat as a father, loving, but intuitive,
might superintend the vagaries of a wayward and talented child. And, in
return, Smoke rewarded him with exhibitions of fascinating and audacious
mischief.

And these brief descriptions of their characters are necessary for the
proper understanding of what subsequently took place.

With Smoke sleeping in the folds of his fur coat, and the collie lying
watchful on the seat opposite, John Silence went down in his motor after
dinner on the night of November 15th.

And the fog was so dense that they were obliged to travel at quarter
speed the entire way.

* * * * *

It was after ten o'clock when he dismissed the motor and entered the
dingy little house with the latchkey provided by Pender. He found the
hall gas turned low, and a fire in the study. Books and food had also
been placed ready by the servant according to instructions. Coils of fog
rushed in after him through the open door and filled the hall and
passage with its cold discomfort.

The first thing Dr. Silence did was to lock up Smoke in the study with a
saucer of milk before the fire, and then make a search of the house with
Flame. The dog ran cheerfully behind him all the way while he tried the
doors of the other rooms to make sure they were locked. He nosed about
into corners and made little excursions on his own account. His manner
was expectant. He knew there must be something unusual about the