[Avodah] Grain weights

[Jonathan Baker]

From: Micha Berger <micha at aishdas.org>
> Subject: [Avodah] Half-Shekel found from the time of Bayis Sheni
 
> On Wed, Mar 19, '08 at 5:27pm EDT, R Gershon Dubin wrote to Areivim:
> : http://www.israelnationalnews.com/News/News.aspx/125612
 
> The Rambam writes (Sheqalim 3:2) that a sheqel is 320 grains of barley.
> R' Chaim Brown <http://tinyurl.com/yswno3> writes:
> > Peter Bernstein writes in "The Power of Gold: The History of an
> > Obsession" (p. 24), "Today the carat has been replaced by the grain ...

> So, given that a grain is a remarkably constant unit of measure, I figured

Except that the grain is not so constant over long periods of history:
there is variation depending on water supply, and growth over the long
term based on genetic improvements.

See, e.g., http://tinyurl.com/23enhk for a study on how to standardize
weights of wheat and barley grains for archaeobotanical comparisons,
noting the growth of grain sizes over time.

Or
http://aob.oxfordjournals.org/cgi/content/full/mcm048v1?ijkey=WOoxibKXbGWFx07&keytype=ref
which is admittedly about a much earlier period, but does note
growth in grain sizes over time, under various kinds of selection pressure.
(this won't mean much for our readers who believe the world didn't exist
then, or that evolution doesn't happen).

> the Rambam's grains would be similar to the British unit "grain", also
> based on barley -- 64.79891 mg. This would make a sheqel (320 barleys)
> equal 20.74 gm. Too large for this coin, I think. It would mean that
> more than a third of the coin is missing.
 
> I'm not sure why the article makes the assumption that this particular
> coin may have been involved in the mitzvah of machatzis hasheqel. But
> if the probability is real, wouldn't it have to be treated as heqdeish?

Do all machtzis hashekel (all the hundreds of thousands of them, if not 
millions each year) remain hekdesh?  It was used to buy flour and animals
for sacrifices - doesn't its use then redeem the hekdesh?  Or did many
tons of silver go out of circulation each year in Adar?

From: Zev Sero <zev at sero.name>
 
> AIUI, many shkalim have been found over the past 200 years or so, and
> they tend to be in the 13-14 gram range.
 
> > The Rambam writes (Sheqalim 3:2) that a sheqel is 320 grains of barley.
 
> The shekel of Moshe's time was 320.  The Shekel Tzori of Chazal was 384.
 
> > So, given that a grain is a remarkably constant unit of measure, I figured
> > the Rambam's grains would be similar to the British unit "grain", also
> > based on barley -- 64.79891 mg.
 
> The Rambam's grains are 1/64 of a dirham, and his dirham was definitely
> no bigger than the Ottoman dirham of 3.2 g (and there is some reason to

Wiki on "Islamic gold dinar" notes that the weight of the dirham & dinar
are set by shari'a, so it is claimed to be pretty consistent since the time
of Muhammad.  But then, they are set relative to the weight of a barley
grain (citing Ibn Khaldun, 14th c. CE), so again it becomes dependent on
grain weight, which may have changed.

> believe it was a bit smaller), which makes a grain no more than 50 mg.

as noted above, grain sizes have grown over time, particularly in the
modern period with conscious genetic breeding.  So the "remarkably
consistent" could be over a limited period of time, while modern barley
grains might be 64.8 mg and the Rambam's 50 mg.
 
--
        name: jon baker              web: http://www.panix.com/~jjbaker
     address: jjbaker at panix.com     blog: http://thanbook.blogspot.com