, as I have often
thought, the reaction against the poetic and contemplative mood which
occasionally predominated in him. The swing of his nature took him
from extreme languor to devouring energy; and as I knew well, he was
never so truly formidable as when for days on end he had been lounging
in his arm-chair, amid his improvisations and his black-letter
editions. Then it was that the lust of the chase would suddenly come
upon him, and that his brilliant reasoning power would rise to the
level of intuition, until those who were unacquainted with his methods
would look askance at him as on a man whose knowledge was not that of
other mortals. When I saw him that afternoon so enwrapped in the music
at St. James's Hall, I felt that an evil time might be coming upon
those whom he had set himself to hunt down.

"You want to go home, no doubt, doctor," he remarked as we emerged.

"Yes, it would be as well."

"And I have some business to do which will take some hours. This
business at Coburg Square is serious."

"Why serious?"

"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 'Encyclopaedia'
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