The Chicago Manual of Style (1982 ed.) lists en-dashes, em-dashes, and
2- and 3-em dashes. Hyphens are shorter than either and en- or em-dash.
Apparently, hyphens are not available on a standard keyboard. The
'hyphen' on a keyboard is actually an en-dash, the dash (usually
obtainable by option-key + hyphen) an em-dash. An em-dash is the length
of two en-dashes.

I disagree that em-dashes are not used by writers. I use them all the
time, and see them in others' writing constantly. They are sometimes
typed in the form of two consecutive en-dashes: --, but not always.
Rules for the 'dash' (em-dash) are given in most punctuation manuals I
know of. They are similar to parentheses in function, and are also used
as between-sentence punctuation when the meaning of the two sentences is
closely related.

As to overuse of the em-dash, I know it is stylistically undesirable,
but I am not sure what sorts of overuse Mr. Safire has in mind. I tend
to overuse em-dashes, so as a standard part of my editing I cut out at
least half of them. Perhaps there is some ideal number of em-dashes per
page that one should not exceed. I would probably frown on more than
three/four em-dashes on one double-spaced, typed page.

Does Mr. Safire mean excessive correct use of em-dash, or use of the
em-dash in incorrect circumstances?

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Johanna Rubba   Assistant Professor, Linguistics
English Department, California Polytechnic State University
One Grand Avenue  • San Luis Obispo, CA 93407
Tel. (805)-756-2184  •  Fax: (805)-756-6374 • Dept. Phone.  756-259
• E-mail: [log in to unmask] •  Home page: http://www.calpoly.edu/~jrubba
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"Understanding is a lot like sex; it's got a practical purpose,
but that's not why people do it normally"  -            Frank  Oppenheimer
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