I could not help laughing at the ease with which he
explained his process of deduction. "When I hear you give your
reasons," I remarked, "the thing always appears to me to be so
ridiculously simple that I could easily do it myself, though at
each successive instance of your reasoning I am baffled until
you explain your process. And yet I believe that my eyes are as
good as yours."
"Quite so," he answered, lighting a cigarette, and throwing
himself down into an armchair. "You see, but you do not
observe. The distinction is clear. For example, you have
frequently seen the steps which lead up from the hall to this
"Well, some hundreds of times."
"Then how many are there?"
"How many? I don't know."
"Quite so! You have not observed. And yet you have seen.
That is just my point. Now, I know that there are seventeen
steps, because I have both seen and observed. By-the-way, since
you are interested in these little problems, and since you are
good enough to chronicle one or two of my trifling experiences,
you may be interested in this." He threw over a sheet of thick,
pink-tinted note-paper which had been lying open upon the
table. "It came by the last post," said he. "Read it
The note was undated, and without either signature or
"There will call upon you to-night, at a quarter to eight
o'clock," it said, "a gentleman who desires to consult you upon
a matter of the very deepest moment. Your recent services to
one of the royal houses of Europe have shown that you are one
who may safely be trusted with matters which are of an
importance which can hardly be exaggerated. This account of you
we have from all quarters received. Be in your chamber then at
that hour, and do not take it amiss if your visitor wear a