The instruments to move into the domes were a 15-inch (38 cm) refractor (East Dome) and a 24-inch (0.6 m) reflector (West Dome). An 8.5-inch (22 cm) transit circle was housed in a separate building further west. The time service continued to control the time ball on Calton Hill and the time gun on Edinburgh Castle by telegraph wire. It also controlled a time gun in Dundee and a clock at Rosyth dockyard. In the 1910s and 1920s research at the ROE led to more accurate pendulum clocks, which remained in service until they had to give way to quartz clocks in the 1960s.