By a peculiarity of idiom the possessive sign is used with a noun in the objective; as, “This is a story _of Lincoln’s,”_ “That is a letter _of the President’s,”_ “A patient _of Dr. Butler’s,”_ “A pupil _of Professor Ludlam’s.”_
In ordinary prose the custom of the best writers is to limit the use of the possessive chiefly to persons and personified objects; to time expressions, as, _an hour’s delay, a moment’s thought;_ and to such idioms as _for brevity’s sake._
Avoid such expressions as, “America’s champion baseball player,” “Chicago’s best five-cent cigar,” “Lake Michigan’s swiftest steamer.”
The question whether we should say “This is somebody’s else pencil,” or “This is somebody else’s pencil,” has been warmly argued by the grammarians, the newspapers, and the schools. If some leading journal or magazine were to write somebody else as one word, others would, doubtless, follow, and the question of the possessive would settle itself. The word _notwithstanding_ is composed of three separate words, which are no more closely united in thought than are the three words _some, body,_ and _else._ Two of the latter are already united, and the close mental union of the third with the first and second would justify the innovation.
But the words are at present disunited. A majority of the best writers still conform to the old custom of placing the possessive with _else._
“People were so ridiculous with their illusions, carrying their fool’s caps unawares, thinking their own lies opaque, while _everybody else’s _were transparent.”—_George Eliot._
Some make a distinction by placing the possessive with _else_ when the noun follows, and with _somebody_ when the noun precedes; as, “This is _somebody else’s_ pencil,” and “This pencil is _somebody’s else.” _This distinction is not generally followed.
The correct use of the pronouns, personal and relative, involves a degree of skill which many speakers and writers fail to possess. The choice of the appropriate pronoun, the agreement with its antecedent, the proper case form, are matters that require careful consideration.
Following _am, are, is, was,_ and other forms of the verb _to be,_ the pronoun must be in the nominative case.
“Are you the person that called?” “Yes; I am _him.”_ The answer should have been, “I am _he.”_