Apostrophe or Of Phrase for Possession
The Apostrophe
Rulebase Summary
There are two acceptable ways for a speaker to express possession: by using an apostrophe and s, or by using an of phrase. An idiomatic double possessive is formed when an apostrophe-s possessive and an of phrase are combined to show one item among several similar items. Not every of phrase is a double possessive — if among cannot be substituted for of, do not use the apostrophe and s.
Examples
A. He is a friend of me.
A. He is a friend of mine.
The of phrase uses a possessive pronoun — 'a friend of mine' is an idiomatic double possessive.
A. That idea of Smith's was never implemented.
A. That idea of Smith's was never implemented.
The double possessive (of + apostrophe s) is correct here — it means one idea among Smith's many ideas.
Transcript Notes
There are two acceptable ways for a speaker to express possession: by using an apostrophe and s (the plaintiff's journal) or by using an 'of' phrase (the journal of the plaintiff).
An idiomatic double possessive combines both — apostrophe s plus an 'of' phrase — to show one item among several similar items (a journal of the plaintiff's = one journal among others). Note: not every 'of' phrase is a double possessive. If 'among' cannot be substituted for 'of,' do not use the apostrophe and s — that phrase is a simple possessive.
If the context suggests a plural rather than a possessive, do not use the apostrophe and s.
Style Guide References (1)
Morson's