A weighlock measured canalboats so tariffs could be set on their cargoes. Each time a captain took on a new cargo, the cargo had to be weighed and a toll paid. Boats were weighed once a year to determine empty weight, then weighed again after loading so the cargo weight could be calculated from the difference. The Syracuse Weighlock stood where the Oswego Canal joined the Erie Canal, forcing boats on either canal to stop in Syracuse for weighing. In 1922 the canals were filled in and became Erie and Oswego Boulevards. The weighlock remained in use as State Engineering headquarters and later opened as the Erie Canal Museum in 1962. To operate it, a boat was drawn into the lock chamber and the gates were closed, small sluice gates at the bottom drained the water, the boat dropped with the water level, came to rest on a wooden cradle, activated the scale, and after the weight was recorded another set of sluice gates refilled the chamber with water from the canal.