Hi Philippe,
This means that this dot will then need to be followed by two spaces
when it is used as a sentence-ending period.
This tradition is no longer current in the US. Though it's obvious there
are still plenty of middle and high school–level teachers and
college-level writing instructors teaching this in the US, not knowing
that books and periodicals in the US haven't been using two spaces after
a sentence-final period for a long time. Let's see how many decades
it'll take for them to forget about this; writing folks who lack an eye
for common practice can be rather obstinate in insisting on what they
heard from some authority during their childhood ;-) After all, people
who should know better still recommend Strunk & White on their websites
(or CMOS, which is actually pretty good, for the most part), despite
none of them ever having read these works.
Might also have to do with age-old textbooks for classes in
touch-typing, though the idea that double sentence spacing makes more
sense with a monospaced font is questionable at best.
(Of course the question whether double sentence spacing is better in
principle is different from the question what common practice is.)
Stephan
