TRONAGE, an ancient customary duty or toll, for the weighing of wool. According to Fleta, trona is a beam to weigh with, mentioned in the stat. Westm. 2, cap. 25. And trona was used for the weighing of wool in a staple or public mart, by a common trona or beam; which, for the trona of wool in London, was fixed at Leadenhall. The mayor and commonalty of London were ordained keepers of the beams and weights for weighing merchants' commodities, with power to assign clerks and porters, &c. of the great beam and balance; which weighing of goods and measures is called trona; and on pain of forfeiture, no stranger is to buy any goods in London before they were weighed on the king's beam.