And did they compare for size? –
About right. But then, so were that other clerk’s, Mason, and Dr Parsons’, and half a dozen people’s –
Josephine Bell, Death on the Borough Council
Apostrophes are used for genitive (or possessive) cases. They are sometimes used as punctuation marks to shorten a sentence. The basis from which we arrive at vagaries of the genitive (or possessive) case is the general rule that a singular boy takes apostrophe “s”; plural “boys” takes apostrophe boys’ outside “s.” The main exceptions are that those words with interior changes take apostrophe “s” in both the singular and plural: man’s, plural men’s, woman’s, women’s, child’s, children’s, cow’s, kine’s, pig’s, swine’s, and that nouns that remain unchanged also take apostrophe “s” in both number one sheep’s (wool), two sheep’s (wool).
There are, however, certain other exceptions: nouns ending in “-nce,” take, in the singular, an apostrophe, as in for patience’ sake, for conscience’ sake, but in the plural, they take “s”, as in for their consciences’ sake.
In accordance with the general rule for the plural; for goodness’ sake is a formula – contrast for mercy’s sake. Nouns ending in “ses” or “sess” or “sses,” or in “sis” or “siss” or “ssis” or “ssiss” or in “xes” (as in Xerxes’ army), take in the singular an apostrophe, as in Pears’ Soap and in “the oasis’ verge,” “molasses’ attraction for children.” Such cases look slightly excessive.
Once it was a general, though is not rare now, practice to form the genitive singular of all nouns ending in “s” and especially those ending in “ss” (hostess) by adding an apostrophe to both the nominative singular (hostess’ duties, your highness’ pleasure).
In the plural, however, the system of genitive was followed (Three hostesses’ houses were in Park Lane). Now it is usual to form the singular nominative by adding “`s” (a hostess’s house, Congress’s policy, your highness’s pleasure).
There is, however, a strong tendency to retain Jesus’ kindness, and Demosthenes’, Socrates’ and other such genitives of Greek proper names.
If we talk of style, the “`s” and the “of form” of the possessive often vary. They sometimes mingle and cause ambiguity. A sentence, like Elizabeth Barret Browning’s “all the hoofs of King Saul’s father’s assess,” should be rewritten. This sentence can be rewritten: “All the hoofs of asses of King Saul’s father” or, better, “all the hoofs of the asses owned by King Saul’s father.” Similarly “he is my wife’s first husband’s only child’s godfather” must be changed to “he is the godfather of the only child of my first wife’s husband.”
Let’s remember that phrases like two weeks’ time, six months’ leave, a year’s subscription, ten years’ experience also need apostrophes. The nominatives, associated with worth, especially, when it is followed by a sum, quantity or other measurements, are followed by apostrophes.
Lane Green writes: After a figure or abbreviation, use a hyphen: three months’-worth of imports.
Double genitive case
The double genitive case is sometimes confusing. But such sentences “A friend of my father’s; three friends of mine”; “that hat of his,” and “dress of Jane’s” do not generally confuse the reader.
There are, however, certain cases that cause confusion: that hat of his, that football of theirs, this pain of mine. How can we justify – this beauty of my sister’s and this famed beauty of my famous sisters?
The loss of distinctive genitive form in a number of pronouns and limited adjectives has weakened English expression, writes Eric Partridge.
Henry Fielding wrote: “Both their several talents were excessive.” But an English writer of the middle age would have written (bothe their or their bothe) talents or (their bothe) talents. It is a distinctive genitive form – “bothe” as distinctive from of the nominative “both.”
Patridge further writes, “Fielding’s both their several talents would, in correct Modern English, be the several talents of both of them, which is wordy in comparison with the middle English “bothe their (or their bothe) several talents.”
The old usage sometimes survives in speech: “She is both their mother, or it is both their faults.” It should be she is the mother of both of them or these are the faults of both of them.