In this week’s edition of The New Yorker, there is an article that includes these two quotes about Larry Summers: “According to a friend of Summers’s, Harvard had wanted . . . ” and later, “According to [Joe Blow], a former student of Summers’s . . . ”
Two questions arise from these quotes. First involves the formation of the possessive with a proper name ending in "s." The writer adds “…’s” to Summers’s name in the possessive case - but shouldn't the possessive be Summers' - or didn't it used to be?
Second, why is the possessive necessary at all? Why not “friend of Summers” or “former student of Summers"? The apostrophe would be necessary if it were, for example, Layton's friend or Layton's student - but shouldn't it be "friend of Layton" not "friend of Layton's"?
The New Yorker has always been kind of the God of Grammar, Usage and Mechanics. Are they slipping, or am I?
Geoff Layton