The weighing scale didn’t know any major technological improvement until the industrial era. It is only starting in the late 18th century that new ways to measure mass appeared that didn’t rely on counter-weights. The spring scale was invented by Richard Salter, a British balance maker around 1770. The spring scale, as the name implies, measures the pressure (or the tension) exerted on a spring to deduce the weight of an object. Spring scales are still fairly common today because they are very cheap to make, but they are not quite as accurate as the electronic systems designed and perfected during the 20th century.