Summer. Uncertain date but likely time for 'The Wandering Corpse' by John Taylor.
1884
The Missing Year. It is possible that this was the year of the cases. known as 'The Delicate Case of the King of Scandinavia' and 'The Service of Lord Backwater'.
1885
January. 'The Case of the Incumbent Invalid' based on 'the dreadful business of the Abernetty family'. April/May. 'The Copper Beeches'. Although set by many commentators in April 1890, this is clearly an earlier case into which Watson slipped references to later cases for the purposes of his introductory argument.
1886
April. 'The Yellow Face'. This is the earliest case to make reference to Holmes's cocaine habit, though Watson had clearly known about it for some while. This year probably saw other cases alluded to by Watson including 'The Woman at Margate', 'The Darlington Substitution Scandal', 'The Arnsworth Castle Business' [written up as 'The Adventure of the Red Widow' by Adrian Conan Doyle], 'Vittoria, the Circus Belle' and 'The Adventure of the Suspect Servant.'
1887
In 'The Five Orange Pips' Watson refers to a long series of cases in • 1887 including
Spring. 'The Netherland-Sumatra Company' and 'The Colossal Schemes of Baron Maupertuis', cases which led to Holmes's ill-health [written up as 'The Case of the Maupertuis Scandal' by June Thomson]. It may be to this period that 'The Horror of Hanging Wood' by John Taylor belongs and one of the best known cases,
April. 'The Reigate Squires'.
August. 'The Secret of Shoreswood Hall' by Denis O. Smith.
September. 'The Adventure of the Silver Buckle'. October. 'Silver Blaze'. Although usually ascribed to October 1888I prefer the earlier dating and must assume the reference to already published cases is wrong.
1888
By this time (as noted in 'The Speckled Band') Watson had made notes of over seventy of Holmes's cases since they met in 1881. (It is possible the reference to 'the last eight years' dates from the date 'The Speckled Band' was written for publication, which was late 1891, so the seventy cases may relate to mid 1884-mid 1891.)
January. 'The Valley of Fear'.
February. 'The Case of the Sporting Squire' (also known as 'Morgan the Poisoner').
Spring. Likely date for 'The Adventure of the Unique Hamlet' by Vincent Starrett.
Summer (July/August). The unrecorded
August. 'The Cardboard Box'. The case also refers to 'the bogus laundry affair' which Holmes had also worked on with Lestrade and which probably happened not long before.
September. 'The Sign of Four' in which Watson meets Mary Morstan whom he marries a few months
later, and settles down again to local practice as a GP; 'The Little Problem of the Grosvenor Square Furniture Van'; and 'The Noble Bachelor'.
Autumn. Throughout the months of August-November, Holmes was probably consulted on the Jack the Ripper case but this was one series of murders that Watson did not write up and probably explains some of the confusion in dates around this period. Michael Dibdin did explore the case in 'The Last Sherlock Holmes Story', which includes Moriarty, but is entirely apocryphal.
October. 'The Hound of the Baskervilles'. Despite attempts to redate this to 1899 or 1900, Watson is clearly recounting an earlier tale. Although he dates it after his marriage it would seem to have happened prior to his marriage, and 1888 is the likeliest date to at least keep within a rough five-year time span from 1884 – the date on Mortimer's stick. It may also seem strange that Watson is happy to drop everything and visit Dartmoor when in the stages of arranging his marriage and without any reference to his fiancee, but as we find elsewhere Mary Morstan was a very flexible and obliging wife who didn't seem to worry about these things, and for the purpose of the story Watson decided to leave out reference to all of this. At the time of Baskerville's death Holmes was involved in the case of
November. 'Colonel Upwood and the card scandal of the Nonpareil Club' [written up as 'The Adventure of the Abbas Ruby' by Adrian Conan Doyle though set in November 1886] and 'Mme Montpensier and Mlle Carere' [written up as 'The Adventure of the Black Baronet' by Adrian Conan Doyle but set in October 1889].
1888/89
After Watson's marriage and before he is next involved in a case ('A Scandal in Bohemia') Holmes is involved in several cases including
1889
March. 'A Scandal in Bohemia'. Despite the internal dating of March 1888 this is clearly set after Watson's marriage. This is the case which deals with Irene Adler.
May/June. 'A Case of Identity'. At this time Holmes reports he has some ten or twelve minor cases in hand. He had also just helped clear up 'The Dundas Separation Case'. The case refers back to Holmes tracing the 'husband of Mrs Etherege' which probably happened a year or two earlier.
June. 'The Adventure of the Fallen Star', 'The Stockbroker's Clerk', 'The Man with the Twisted Lip' and probably 'The Engineer's Thumb'. Either now or earlier was also the case of 'Colonel Warburton's Madness' mentioned in 'The Engineer's Thumb' [written up as 'The Adventure of the Sealed Room' by Adrian Conan Doyle