Roman camp - units of measure used by Polybios

[triarius354]

Actually, a Republican scutum I have is 4 feet high! not so far off?

4 attic or english feet - c. 1,2 metres, I guess...
According to dr Dobson feet used by Polybios was 0,355 m. Shield of four "royal" feet would have 1,42 m height. Even shield from Kasr-el-Farit had only 1,28 m.
Trouble is that if we agree with dr Dobson that foot used by Polybius is 0,355 m long, every item of equipment he describes would by larger. For example - shield of velites - 1,065 m. Quite a large one for light-armed troops.

Why this one, and not the 0,296mm foot?

I believe Dobson has got himself into a bit of circular reasoning here, but I may be wrong.

He seems to say that Polybius' description of the commander's tent (praetorium) must be in Hellenistic feet (which he quotes as 0,355mm) because Polybius uses a measurement called the tetraplethron. (I don't think I've come across such a large "foot" before -- can anyone corroborate this measurement?)

However, tetraplethron simply means 4 plethra, a measure of 100 Greek feet. Why could Polybius not have used the Attic foot of 0,296mm? And thus his measurements would have satisfied his Roman readers.

Later, Dobson seems to be struck by the fact that 120 Roman feet = 100 "Hellenistic" feet. And multiples of 120 are common in Roman measurement (e.g. the actus quadratus being 35.5m x 35.5m, which would be 100 of Dobson's "Hellenistic" feet square). So his "Hellenistic" measurements would tally with standard Roman practice. I think.

Maybe I have missed a crucial step in his argument? :|

Dr Dobson's arguments are sound if we agree with his assumption in the beginning, but the question remains on what basis are they founded? If we assume that Polybius' was refering to this "hellenistic/royal foot" when describing Roman camp, he surely would have used it in description of weapons, space allowed for phalangites and legionaires etc, right?
I have found a reference to "royal foot" in article by Dieter Legemann: "Recovery of the Ancient System of Foot/Cubit/Stadion – Length Units".
He refers to "pous basilikos" as 0,355m, but does not state where, when and by whom was it used. Still, the name "hellenistic foot" does not appear, and most probably was not original name of that unit of measure.

Regards,