 chosen? If
they had followed him the first day I argued that they would follow him also the
second. You may have observed that I twice strolled over to the window while Dr.
Mortimer was reading his legend.«
    »Yes, I remember.«
    »I was looking out for loiterers in the street, but I saw none. We are
dealing with a clever man, Watson. This matter cuts very deep, and though I have
not finally made up my mind whether it is a benevolent or a malevolent agency
which is in touch with us, I am conscious always of power and design. When our
friends left I at once followed them in the hopes of marking down their
invisible attendant. So wily was he that he had not trusted himself upon foot,
but he had availed himself of a cab so that he could loiter behind or dash past
them and so escape their notice. His method had the additional advantage that if
they were to take a cab he was all ready to follow them. It has, however, one
obvious disadvantage.«
    »It puts him in the power of the cabman.«
    »Exactly.«
    »What a pity we did not get the number!«
    »My dear Watson, clumsy as I have been, you surely do not seriously imagine
that I neglected to get the number? No 2704 is our man. But that is no use to us
for the moment.«
    »I fail to see how you could have done more.«
    »On observing the cab I should have instantly turned and walked in the other
direction. I should then at my leisure have hired a second cab and followed the
first at a respectful distance, or, better still have driven to the
Northumberland Hotel and waited there. When our unknown had followed Baskerville
home we should have had the opportunity of playing his own game upon himself and
seeing where he made for. As it is, by an indiscreet eagerness, which was taken
advantage of with extraordinary quickness and energy by our opponent we have
betrayed ourselves and lost our man.«
    We had been sauntering slowly down Regent Street during this conversation,
and Dr. Mortimer, with his companion, had long vanished in front of us.
    »There is no object in our following them,« said Holmes. »The shadow has
departed and will not return. We must see what further cards we have in our
hands and play them with decision. Could you wear to that man's face within the
cab?«
    »I could swear only to the beard.«
    »And so could I --
