[Avodah] Length of Archeological Ammah [Avodah V27#116, msg 10]

[Michael Poppers]

RZS noted:
>>> Taking a dirham of 64/72 of 3.205 g, or 2.85 g, yields a revi'is of
>>> 77 ml, and therefore an etzba of 1.924 cm and an amah of 46.176 cm....

Private MP:
>> [private MP] Could you review onlist the source(s) for the equations
>> between those different measures? Thanks!

> The ratio is simple:  An amah is 24 etzba'os.
> A revi'is is 10.8 cubic etzba'os {hereafter "ce" --MP}.
> And the Rambam says that a revi'is is a volume of water that
> weighs 27 dirham.

(For some pertinent WWWpages, see 
http://dafyomi.shemayisrael.co.il/pesachim/insites/ps-dt-109.htm , 
http://www.vbm-torah.org/archive/pesachim59/pesachim21.htm , and 
http://www.aishdas.org/avodah/vol10/v10n146.shtml#08 ....)

and R'Micha noted privately:
> The metric system is set up ...           [s]uch that
>    1 cc (a/k/a cm^3) = 1 ml
which means (to reword what RZS noted privately, so any mistakes
are mine :)) that when we talk of a r'vi'is containing 77ml, we're
talking of a volume bounded by 77cc, hence one ce is equivalent to
77/10.8=>approximately 7.13cc and that, applying the cube root to each
side, one etzba is approximately 1.925cm. Thanks!

All the best from
Michael Poppers * Elizabeth, NJ, USA