dogged manner, "but I was to ask you to give me your word that
neither of your companions is a police-officer."

"I give you my word on that," she answered.

He gave a shrill whistle, on which a street Arab led across a
four-wheeler and opened the door. The man who had addressed us
mounted to the box, while we took our places inside. We had
hardly done so before the driver whipped up his horse, and we
plunged away at a furious pace through the foggy streets.

The situation was a curious one. We were driving to an unknown
place, on an unknown errand. Yet our invitation was either a
complete hoax,--which was an inconceivable hypothesis,--or else
we had good reason to think that important issues might hang upon
our journey. Miss Morstan's demeanor was as resolute and
collected as ever. I endeavored to cheer and amuse her by
reminiscences of my adventures in Afghanistan; but, to tell the
truth, I was myself so excited at our situation and so curious as
to our destination that my stories were slightly involved. To
this day she declares that I told her one moving anecdote as to
how a musket looked into my tent at the dead of night, and how I
fired a double-barrelled tiger cub at it. At first I had some
idea as to the direction in which we were driving; but soon, what
with our pace, the fog, and my own limited knowledge of London, I
lost my bearings, and knew nothing, save that we seemed to be
going a very long way. Sherlock Holmes was never at fault,
however, and he muttered the names as the cab rattled through
squares and in and out by tortuous by-streets.