If the story dates are not indicated, why do we require them? The short answer is "We don't", but there are other points to consider. If we believe that the story is the essential thing; in other words, we treat the Canon as simply entertainment, then background details are not essential, and we need not trouble ourselves with them. However, for many readers of the Canon, there is always the temptation to try one's hand at reasoning as the Master does. As he observed: "You know my methods, Watson . . .". With such a problem as discovering the date on which a story occurred, we have a situation in which there is a certain amount of data to provide the clay for our bricks. So we try to discover "When?". Let's take an example -- the first one in the Canon. In A Study in Scarlet, we are told how Watson landed on the quay at Portsmouth, still convalescent from his campaign wound(s) and subsequent attack of enteric fever. When we know that date - and it is possible to find it from the local newspapers, as the S.S. "Orontes" was an actual troopship -- we can then estimate how long it took him to drift up to London, to find that the cost of living there exceeded his means, and at length to decide that he would share lodgings with the somewhat strange individual to whom his old friend Stanford had introduced him. On the fourth of the following March he is invited to join his flat-mate in investigating a murder case. What was the year? It is a puzzle-solving problem - the answer turns out to be 1881, by the way - and can be the first of many we are faced with in studying the Canon. But, unlike number puzzles, crossword puzzles, "Jeopardy™" and "Trivial Pursuit™", it can involve knowledge from many different fields. As the puzzle becomes more complex the pleasure in solving it increases.
How much (dis)agreement is there between them? Oh dear. As one might expect, there is less agreement on average than there is disagreement. The greatest level of agreement between two chronologists is exactly two-thirds (40/60). The lowest is under one-quarter (13/60) from Dr. J. F. Christ (see below), whose views on the question of "When?" were not often shared by other writers. Nevertheless, he argued his cases with considerable skill. For a comparative table of agreements, see Peck & Klinger (1996).
Why are there these disagreements? As noted above, some story dates are not given at all, some can be deduced from internal evidence, some are stated to be disguised, some are given but may be disguised; only one is inarguable (the outbreak of World War I in LAST) though all chronologists assign the same dates to a few stories. Of those that depend on internal evidence, several relate to a single event -- Dr. Watson's marriage, which raises a further question relating to another topic - "How many times was Dr. Watson married?".
If there is a logical contradiction between items of the evidence, what weight do we give to these different items? Generally speaking, the kind of weight which the "reasonable man or woman" beloved of the legal profession would put on a statement offered as evidence in Court. One must always remember that Watson was a paid author writing for publication, and therefore strict accuracy is always likely to be sacrificed to the demands of the well-told tale. ACD's own words on this question should be always borne in mind; "One must be masterful in these matters". If the story required a railway line where there was nothing of the kind, then he invented one. It is the task of the chronologer to solve the often almost-insuperable problems that this involves. But we can lead ourselves astray in our reasoning, and an example of misleading evidence follows. Prof. Zeisler's chronology relied heavily on Watson's descriptions of the weather as though these held good for all of southern England on a particular day. He would then compare Watson's descriptions with those printed in The Times for southern England, and search until he found a close or preferably an exact match. Unfortunately for his argument, any Englishman or woman could have warned him that the only constant element in the English climate is its changeability, and likewise its variation from one place to another; what are now termed "microclimates". A sunny day in West London could have been a showery day in the adjoining county of Buckinghamshire.
By way of contrast, in the story "The Cardboard Box", sixteen out of seventeen chronologies assign a date of 1889 or earlier to the story. Yet contemporary railway timetables show that New Brighton railway station, which is categorically referred to, was not built until 1891. We also know from other stories in the Canon that Holmes had vanished at the Reichenbach Falls in April 1891. The story occurs in August. A solution to this is left as an exercise for the reader.
Reference sources: Contemporary reference books such as Bradshaw's Railway Timetable are hard to come by save at inflated prices, though a reprint of the August 1887 Bradshaw was put out by David & Charles in 1968, and can be found in many reference libraries. Baedeker's Guides from the Canonical period are more easily and cheaply found in second-hand bookstores.
The most recent complete edition of the Canon is the Oxford University Press 9-volume edition, which has many annotations dealing with chronological points. Gasogene Press is steadily turning out another annotated edition under the editorship of Leslie Klinger, which has so far reached four volumes: STUD, SIGN, the Adventures and the Memoirs. But as always, the best research tool is an alert and interested mind.
Copyright © Chris Redmond 2015