"A considerable crime is in contemplation. I have every reason to believe
that we shall be in time to stop it. But to-day being Saturday rather
complicates matters. I shall want your help to-night."

"At what time?"

"Ten will be early enough."

"I shall be at Baker Street at ten."

"Very well. And, I say, doctor! there may be some little danger, so kindly
put your army revolver in your pocket." He waved his hand, turned on his
heel, and disappeared in an instant among the crowd.

I trust that I am not more dense than my neighbors, but I was always
oppressed with a sense of my own stupidity in my dealings with Sherlock
Holmes. Here I had heard what he had heard, I had seen what he had seen,
and yet from his words it was evident that he saw clearly not only what
had happened, but what was about to happen, while to me the whole
business was still confused and grotesque. As I drove home to my house in
Kensington I thought over it all, from the extraordinary story of the
red-headed copier of the "Encyclopædia" down to the visit to Saxe-Coburg
Square, and the ominous words with which he had parted from me. What was
this nocturnal expedition, and why should I go armed? Where were we going,
and what were we to do? I had the hint from Holmes that this smooth-faced
pawnbroker's assistant was a formidable man--a man who might play a deep
game. I tried to puzzle it out, but gave it up in despair, and set the
matter aside until night should bring an explanation.

It was a quarter-past nine when I started from home and made my way across