[Avodah] Size of Isoron

[Akiva Blum]

The gemorah (pesochim 109a) states that a revi'is is 2 fingers by 2 finger
by 2.7 fingers. This is a total of 10.8 cubic fingers. A beitza is
therefore, as two thirds of a revi'is, 7.2 cubic fingers. An isoron is 43.2
beitzim (Rashi beshalach 16:36, Shach Y.D. 97:5). Therefore an isoron is
311.04 cubic fingers (Y.D. Ramo 324:1). (There are many ways of working this
out, they all come to the same thing.)

The mishna (menochos 11:5) states that the lechem haponim, when spread out
flat, were 5 tefochim by 10 tefochim. Rashi (beitzo 22b) says they were a
tefach thick. That equals 20 fingers by 40 fingers by 4, a total of 3200
cubic fingers. Each lechem was made of 2 isoronim (vayikro 24:5), so one
isoron should be 1600 cubic fingers.

Lechem haponim were baked matzos (menochos 97a). How could the flour be
311.04 cubic fingers per isoron, but the baked finished product be 1600
cubic fingers, more than five times as much?

(BTW, there is a nafke mina lehalocho.)

Akiva