Steelyard balance
Romana (balanza de brazos desiguales)
- Date
- c. 200 BCE · confidence low
- Place
- Rome, Latium, Italy
- Credited to
- Merchants of the classical Mediterranean
- Field
- Knowledge & symbols
⚠️ Disputed: the sources disagree.
What it is
A lever with a short arm for the object and a long graduated arm along which a fixed weight is slid until balance. It weighed heavy loads with a single weight, was portable and became the weighing instrument of Roman trade.
The origin of the unequal-arm balance is uncertain: well-documented Roman steelyards exist from the Republican period, and steelyards from the Warring States are known in China, possibly independent.
What it led to
- weighing heavy goods in ports and markets
- the traditional steelyard that survived in markets until the 20th century
- platform scales and spring balances