Choose a 221B Baker Street on a map. After returning home, put a hat on a laboratory table and examine it.
Looked at a ribbon on the right. Holmes will conclude that the man is married.
Then rotate a hat, so you can look inside it. Notice a heat marks on the front tip and a label inside. See also a grey hair and small scratches on both sides.
All those evidences let Holmes deduce that the mysterious man is a grey-haired judge wearing glasses.
Go to the bookshelf on the right and take a judges' register. Put it on a worktable.
You will see a board with photos of three judges typed by Sherlock. Click on the appropriate identification on the list under each of them.
- Sir Lawrence Bromsby: smokes a cigar, wears glasses, married
- Sir Coutts Beckett: wears a hat, smokes a cigar, wears glasses, married, grey hair
- Barry Amstetton: wears a hat, wears glasses, married, grey hair
Only sir Beckett fulfills all conditions, so he is the one Sherlock is looking for.
As a result of conversation between Sherlock and Watson, in the you can find another entry in "Documents" : September 1898 "Globe Explorer"
At the end, choose a map of London and Beckett's mansion.