Guide to LaTeX (4th Edition) (Tools and Techniques

2.7. Fine-tuning text 29
simply a symbol for the blank which is otherwise invisible.) Both these
methods insert the normal interword spacing; in addition, ˜ is a protected
space that prevents the line from being broken at this point. The above
examples should be typed in as i.˜e., Prof.˜Jones, and Phys.\ Rev.,
producing i. e., Prof. Jones, and Phys. Rev. with the correct spacing and
forcing the first two to be all on one line. In the third case, there is nothing
wrong with putting Phys. and Rev. on different lines.
A period following an upper case letter is not interpreted as the end
of a sentence, but as an abbreviation. If it really is the end of a sentence,
then it is necessary to add \@ before the period in order to achieve the
extra spacing. For example, this sentence ends with NASA. It is typed in
as This sentence ends with NASA\@.
French spacing
The additional interword spacing between sentences can be switched
off with the command \frenchspacing, which remains in effect until
countermanded with \nonfrenchspacing. In this case, the command \@
is ignored and may be omitted. This paragraph has been printed with
\frenchspacing turned on, so that all word spacings within one line are
the same. It corresponds to the normal rule for non-English typesetting.
Character combinations “ ‘ and ’ ”
A small spacing is produced with the command \,. This may be used, for
example, to separate the double quotes “ and ” from the corresponding
single quotes ‘ and ’ when they appear together. For example, the text
‘‘\,‘Beginning’ and ‘End’\,’’ produces “ ‘Beginning’ and ‘End’ ”.
Inserting arbitrary spacing
Spacing of any desired size may be inserted into the text with the commands
\hspace{space}
\hspace*{space}
where space is the length specification for the amount of spacing, for
example 1.5cm or 3em. (Recall that one em is the width of the letter M in
the current typeface.)
This command puts blank space of width space at that point in the
text where it appears. The standard form (without *) has no effect if it
should come at the beginning of an output line, just as normal blanks are
removed at the beginning of lines. The *-form, on the other hand, inserts
the spacing no matter where it occurs.
A blank before or after the command will also be included: