really be a mystery—­and cite me a case if you can (a really difficult and perplexing case) in which the criminal has not escaped.  Mind!  I don’t charge the police with neglecting their work.  No doubt they do their best, and take the greatest pains in following the routine to which they have been trained.  It is their misfortune, not their fault, that there is no man of superior intelligence among them—­I mean no man who is capable, in great emergencies, of placing himself above conventional methods, and following a new way of his own.  There have been such men in the police—­men naturally endowed with that faculty of mental analysis which can decompose a mystery, resolve it into its component parts, and find the clue at the bottom, no matter how remote from ordinary observation it may be.  But those men have died, or have retired.  One of them would have been invaluable to you in the case you have just mentioned to me.  As things are, unless you are wrong in believing in the young lady’s innocence, the person who has stolen that bank-note will be no easy person to find.  In my opinion, there is only one man now in London who is likely to be of the slightest assistance to you—­and he is not in the police.”

“Who is he?” asked Mr. Troy.

“An old rogue, who was once in your branch of the legal profession,” the friend answered.  “You may, perhaps, remember the name:  they call him ‘Old Sharon.’”

“What!  The scoundrel who was struck off the Roll of Attorneys, years since?  Is he still alive?”

“Alive and prospering.  He lives in a court or lane running out of Long Acre, and he offers advice to persons interested in recovering missing objects of any sort.  Whether you have lost your wife, or lost your cigar-case, Old Sharon is equally useful to you.  He has an inbred capacity for reading the riddle the right way in cases of mystery, great or small.  In short, he possesses exactly that analytical faculty to which I alluded just now.  I have his address at my office, if you think it worth while to try him.”

“Who can trust such a man?” Mr. Troy objected.  “He would be sure to deceive me.”

“You are entirely mistaken.  Since he was struck off the Rolls Old Sharon has discovered that the straight way is, on the whole, the best way, even in a man’s own interests.  His consultation fee is a guinea; and he gives a signed estimate beforehand for any supplementary expenses that may follow.  I can tell you (this is, of course, strictly between ourselves) that the authorities at my office took his advice in a Government case that puzzled the police.  We approached him, of course, through persons who were to be trusted to represent us, without betraying the source from which their instructions were derived; and we found the old rascal’s advice well worth paying for.  It is quite likely that he may not succeed so well in your case.  Try the police, by all means; and, if they fail, why, there is Sharon as a last resort.”