The relation of the Roman Modius to the Alexandrian-Greek medimnos appears to be only a coincidence, as the former is one-third of a Roman cubic foot, and the latter an Alexandrian cubic foot increased in water-wheat ratio.
The New Roman Pound
Trade with Egypt led the Romans, not only to use the Alexandrian medimnos, but also to put aside the As for commercial purposes and adopt a standard taken from the Alexandrian talent. Its 1500 double-shekels made 125 libræ each of 12 unciæ = 437 grains. The libra was thus = 5244 grains as compared with the As = 5049 grains.
A further uncial division of the libra made the Uncia either of 6 sextulæ, 24 scrupuli, 48 oboli, 144 siliquæ, or of 12 semi-sextulæ, 144 siliquæ.
The siliqua was a little less than the Eastern qirát, being 3·03 grains instead of the 3·1616 grain carat of the Ptolemaïc series of weights.
Table of Roman Weights and Measures of Capacity
Weights
OLD WEIGHTS (MINT SERIES)
| As = 5040 grs. | 12 | unciæ |
| Deunx | 11 | „ |
| Dextans | 10 | „ |
| Dodrans | 9 | „ |
| Bessis | 8 | „ |
| Septunx | 7 | „ |
| Semissis | 6 | „ |
| Quincunx | 5 | „ |
| Triens | 4 | „ |
| Quadrans | 3 | „ |
| Sextans | 2 | „ |
| Uncia = 420 grs. | 1 | „ |
NEW WEIGHTS (MEDICINAL SERIES)