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
proceeding, because it was contrary to the habits of his whole life not
to be asleep at this hour on the mat in front of the fire. He kept
looking up into his master's face, as door after door was tried, with an
expression of intelligent sympathy, but at the same time a certain air
of disapproval. Yet everything his master did was good in his eyes, and
he betrayed as little impatience as possible with all this unnecessary
journeying to and fro. If the doctor was pleased to play this sort of
game at such an hour of the night, it was surely not for him to object.
So he played it, too; and was very busy and earnest about it into the
bargain.

After an uneventful search they came down again to the study, and here
Dr. Silence discovered Smoke washing his face calmly in front of the
fire. The saucer of milk was licked dry and clean; the preliminary
examination that cats always make in new surroundings had evidently
been satisfactorily concluded. He drew an arm-chair up to the fire,
stirred the coals into a blaze, arranged the table and lamp to his
satisfaction for reading, and then prepared surreptitiously to watch the
animals. He wished to observe them carefully without their being aware
of it.

Now, in spite of their respective ages, it was the regular custom of
these two to play together every night before sleep. Smoke always made
the advances, beginning with grave impudence to pat the dog's tail, and
Flame played cumbrously, with condescension. It was his duty, rather
than pleasure; he was glad when