A reader asks: How do we write the possessive form of names that end in s – for example, Davis's or Davis'? This is not only a long-standing area of disagreement and inconsistency among writing guides but also brings up how confusing and unstandardized many English possessive forms really are.
To answer the name question first: It varies. Some journals use the apostrophe alone, with a singular name ending in s, some use an apostrophe-s. I vaguely remember being taught to avoid the possessives on names with one syllable ("Keats' poetry") and to add it to multisyllabic names ("Davis's hernia") – or was it the other way around? Some houses do in fact have variable rules within the same publication. Jesus and Moses, for example, and Greek names such as Ulysses and Socrates, are often exceptions, and are written in their possessive forms without an extra s ("Jesus' name", "Socrates' argument"). The Globe and Mail is admirably consistent on this one: We add the logical apostrophe-s to everything, including Davis, Jesus and Socrates (we write Jesus's name and Socrates's argument – and Microsoft Word is trying to correct me as I write this). But sometimes a very sibilant name can sound really awkward in this form – Berlioz's symphony – and you might want to think about rewriting the sentence to avoid it ("the symphony by Berlioz"). And if you're talking about something that belongs to the Davis family you write "the Davises' house."
But The Globe and Mail's style guide also notes that recasting these sentences to avoid too many sibilants can itself end up in awkward contortions, and that it is preferable to write "the hostess's gown" than "the gown of the hostess." The latter just sounds stilted. And there will always be exceptions to everything: When it comes to odd team names like the White Sox, we don't add an extra s for a possessive form; we write "the Sox' losing streak." How is it possible to keep all this straight?
Another uncomfortable question for the copy editors is the word sake, as in "for goodness' sake" (apostrophe or none?). I think most editors would add an apostrophe here, as The Globe does, as it is a possessive, but in speech we don't pronounce it as such – we don't add an extra syllable. It's basically just weird.
So are the truly vexing constructions such as "two weeks holiday." Convention has it that weeks is possessive here and should be written as weeks', but the practice is falling into disuse. Many papers (including this one) have decided that two weeks is actually a descriptive phrase and should be left without an apostrophe. There are many phrases that involve such "adjectival possessives": a first ministers conference, a teachers college, a hitchhikers guide. To simplify punctuation, modern newspapers choose to see "first ministers" as functioning like an adjective and therefore not requiring an apostrophe. I find it tough to follow this rule: I admit I crave the apostrophe on teachers college. And I note, shaking my head at the impossibility of standardizing this ludicrous language, that newspapers still make exceptions for singular words: They write "a week's vacation" and "a day's work." (The Globe's style guide explains gnomically, "Idiom requires it.") And conventions still hold for such well-known phrases as the Seven Years' War.
Now, a little space for the formerly prescribed question of the double genitive. This is a very strange English idiom: It's when you say "they are friends of mine" or "it's a quirk of his." It has been questioned by grammarians because "of" and "mine" both signify possession, so maybe they are redundant. It's not really debated any more, as it's clearly a fully functioning and common idiom in this language, especially when pronouns (mine, his) are involved. It can start to sound a little convoluted, though, when the possessive is followed by a noun or a name: a friend of the Davises', an idiosyncrasy of Harper's, a choice of my grandfather's. You can usually avoid the apostrophe in these sentences, either by just cutting it ("a choice of my grandfather" sounds just fine) or by rewriting it entirely ("it was a choice my grandfather had made"). This newspaper lets writers decide what sounds best, without imposing any rules. And who could, really, impose rules on this worms' can?