Who invented?

In 5000 BC, the Egyptians were the first people to build the beam balance and weigh goods. Pans hung form both ends of a balance beam. In one pan the load to be weighed was placed, and in the second pan the weights were put, until both the pans were perfectly balanced. The earliest and the smallest unit of weight was a grain of wheat and it was used to weigh gold. the steelyard has been used as a weighing device since 2000 BC. It has two arms of different lengths and uses a counterweight that slides along the calibrated longer arm to counterbalance the load on the other arm and indicate its weight.