🚀 go-pugleaf

Peter da Silva (peter@baylor.UUCP) writes in net.internat:

> Officially, the US dollar symbol has two vertical bars (it's derived from
> overprinting U and S, with the curve of the U deleted). The Australian dollar
> sign has only one vertical bar (to distinguish it from the US dollar sign).

Nope.  I quote from volume 2 of "A History of Mathematical Notations"
by Florian Cajori (Open Court Publishing, 1929, reprinted 1952).

The discussion begins on page 15:

#    There are few mathematical symbols the origin of which has given
#    rise to more unrestrained speculation and less real scientific
#    study than has our dollar mark, $.  About a dozen different theories
#    have been advanced by men of imaginative minds, but not one of these
#    would-be historians permitted himself to be hampered by the under-
#    lying facts.  ...  Breathes there an American with soul so dead
#    that he has not been thrilled with patriotic fervor over the "U.S.
#    theory" which ascribes the origin of the $ mark to the superposition
#    of the letters U and S?  ...  As a matter of fact, no one has ever
#    advanced evidence [for this] in the form of old manuscripts ...

This and other theories are then discussed at length, with several
illustrations from old manuscripts.  And the discussion wraps up
on page 29 with:

#    Conclusion.--  It has been established that the $ is a lineal
#    descendant of the Spanish abbreviation p-superscript-s for "pesos",
#    that the change from the florescent p-superscript-s to $ was made
#    about 1775 by English-Americans who came into business relations
#    with Spanish-Americans, and that the earliest printed $ dates back
#    to the opening of the nineteenth century.

The volume's addenda include a confirmatory reference to new research
in the Scientific Monthly for September 1929, pages 212-216.

Thus the $ with a single vertical stroke is the original form.
The form with two strokes was little used before 1800.

Mark Brader
p.s. "Florescent" is defined as "bursting into flower" in my dictionaries.
      Here it obviously means "ornate".