EM DASH
6.90 Indicating sudden breaks. An em dash or a pair of em dashes may indicate a sudden break in thought or sentence structure or an interruption in dialogue. (Ellipsis points may also serve this purpose; see 11.45.)
``Will he--can he--obtain the necessary signatures?'' asked Mill.
``Well, I don't know,'' I began tentatively. ``I thought I might--''
``Might what?'' she demanded.
If the break belongs to the surrounding sentence rather than to the quoted material, the em dashes must appear outside the quotation marks.
``Someday he's going to hit one of those long shots, and''--his voice turned huffy--``I won't be there to see it.''
... we danced for a while, got some drinks, kept dancing—. we went outside a couple times. then, finally exhausted, we left and went to ihop. ...
(black book, 200708201708 j.)
... stay up playing some cribbage, get online for a bit, pass out on the computer for a bit, manage to get my contacts out and go to sleep.
wake up on sunday,—wrote about it before—
monday, i went to silverbow café for a bagel, cookie, and latté. ...
(black book, 200708072130 r, j.)
... i tried to push some love onto her. my bloody valentine, sometimes: ``i don’t know how you could not love me now—''
(blue book, april sixth, 5:43pm.)
I have taken two liberties. Nietzsche occasionally uses dots, usually four, as a punctuation mark; for example, but by no means there alone, at the end of sections 62 and 227. In serious works in the English-speaking world dots are so generally taken to indicate omissions that it did not seem advisable to follow Nietzsche's usage. Dashes have therefore been used instead.
(Walter Kaufmann, Translator's Preface, Beyond Good and Evil.)
Men, not high and hard enough to have any right to try to form man as artists; men, not strong and farsighted enough to let the foreground law of thousandfold failure and ruin prevail, though it cost them sublime self-conquest; men, not noble enough to see the abysmally different order of rank, chasm of rank, between man and man--such men have so far help sway over Europe, with their ``equal before God,'' until finally a smaller, almost ridiculous type, a herd animal, something eager to please, sickly, and mediocre has been bred, the European of today--
(FN, BGE 62, WK tr.)
Ellipses
11.51 Definition and form. An ellipsis--the omission of a word, phrase, line, paragraph, or more from a quoted passage--is indicated by ellipsis points (or dots), not by asterisks. Ellipsis points are three spaced periods ( . . . ), sometimes preceded or followed by other punctuation. They must always appear together on the same line, but any preceding punctuation may appear at the end of the line above (see also 11.64).
Hyphens and Dashes
EM DASH
6.87 Versatility and frequency of use. The em dash, often simply called the dash, is the most commonly used and most versatile of the dashes. To avoid confusion, no sentence should contain more than two em dashes; if more than two elements need to be set off, use parentheses (see 6.98).