Grey painted wooden case with glazed door. Lower dial with hour and minute hands and seconds bit. Upper dial with sweep seconds hand only mounted on inside of door. Black japanned casting carries pendulum, countwheel, gravity arm and solenoids. Subsidiary seconds counter fitted.
Electrically reset gravity escapement. With each swing of the seconds pendulum, the countwheel is advanced one tooth. Each half minute, a detent is tripped and an L-shaped lever falls down. It carries a roller which impulses a specially shaped arm attached to the pendulum, keeping it in motion. The other arm of the lever makes a contact which energises the solenoids . These pull in an armature which resets the lever ready for the next half-minute impulse. The same current also flows in a series circuit to the solenoids operating the dial(s). There is a link below to an animation by Bosco Clocks. As the hands move only twice a minute, a subsidiary seconds counter, which provides an impulse at each swing of the pendulum, has been fitted to this clock which was used to time and control ionospheric observations at the Moggil field station, starting in the International Geophysical Year in 1958.
Synchronome pendulum clocks were also widely used in the University to operate slave dials in lecture rooms and to control bells and timers (see Item 27) The Synchronome Electrical Company of Australasia built clocks in Brisbane under licence from Frank Hope-Jones' Synchronome Company in England. They built the clocks in the towers of South Brisbane Town Hall (1904) and Brisbane City Hall (1930).