# [e-gold-list] Re: UNITS, UNITS, UNITS, UNITS... please e-gold

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> >e-gold is using the wrong gram-ounce conversion.  The correct unit is
> >one troy ounce = 31.103477 grams, exactly, not 31.103, which is what
> >e-gold currently uses.  I can document the source of the 31.103477 if
> >you care,
>
> Yes, document it thoroughly please.

JP, here's the message I sent to the e-gold-tech list, which
thoroughly documents where this number comes from.  Go to the NIST web
site (see link) and check for yourself.

Executive summary:

The e-gold system currently uses a ratio of 31.103g = 1 troy ounce for
all their conversions (see the SCI documentation, for example).  This
is not the correct ratio.  This makes a big difference if e-gold has
to interface with external systems which use grams as an internal unit
of account.  e-gold needs to fix this, instead of having external
systems use its incorrect value.  This difference results in a
discrepency of about 0.0015%, which isn't much, but it introduces a
lot of complexity in accounting for these external systems.

Details:

According to accepted international standards, the pound is defined in
reference to the gram.  Specificly, one pound is exactly equal to
453.59237g, by definition[1].

Note that when we say "one pound" we are refering to "one avoirdupois
pound".  When we talk about ounces of gold, we are refering to "Troy
ounces".  There are exactly (by definition, of course) 12 Troy ounces
in one Troy pound.  There are exactly 7000 grains in one avoirdupois
pound, and exactly 5760 grains in one Troy pound.  Fortunately, there
is no such thing as a "Troy grain" or an "avoirdupois grain"; ie, a
grain is a grain.

Therefore, to find out how many grams are in a Troy ounce, we
calculate the following:

1 Troy ounce / 12 (troyounce/troypound) * 5760 (grains/troypound) /
7000 (grains/avoirdupoispound) * 453.59237 (grams/avoirdupoispound)

=

31.103477

So there are exactly (by definition) 31.103477 SI grams per Troy
Ounce.

e-gold, you need to fix your conversions.  Otherwise all the other
gold systems (like thegoldcasino, Standard Reserve, and others) will
be using the wrong units, or they will need to make special
conversions for you, or something else.

Thanks

References:

[1] For a reference on the definitions of all the weights in ordinary
use, please see the NIST website:

http://ts.nist.gov/ts/htdocs/230/235/appxc/appxc.htm

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