Persian Equal-armed balance (Jeweller's scales) with 10 1/2" ornamental polished steel beam, with gallows suspension and 2 brass pans 5" diam., supported by woven silvered cords. Sensitivity 1.2gr., early 19th C.

These Persian jeweller's scales with ornamental polished steel beam and gallows suspension are dated to the early 19th century. A jeweller used these scales for weighing gemstones in what is now modern-day Iran. Equal-arm balances of this type are the simplest and earliest method of weighing. They consist of a beam that has a pan suspended at either end. In use objects to be weighed are placed in one pan while weights of a known mass are placed in the other pan until the two are balanced with the bar level. The product of these weights gives the mass of the commodity being measured.