The Brillie Master clock was a French invention which was used by the Paris Observatory to transmit time signals to slave clocks. It has a 1/2 second pendulum made of Invar with a horse-shoe shaped magnet as the bob, one pole of which passes through an electromagnet, and a brass sphere above, which is mounted on a threaded part of the rod and is used to rate the clock. This clock has the names MAGNETA and BRILLIE FRERES on the dial.
The clock is mounted on a marble slab for rigidity, and the wiring runs in channels cut into the back of the marble. Around the impulse coil are two small pivoted iron cores which are used as fine tuning to the rating of the clock.
The dial is easily removable to give access to the battery mounting and pendulum suspension. The original Brillie batteries had a mounting flange built into their top surface, but a U2/MN1300 dry cell can be mounted using a modified capacitor clamp. Just to the left of the pendulum and level with the battery mounting bracket can be seen the pawl on the pendulum which turns an index wheel on the back of the movement which drives the clock.
The index wheel is rotated one tooth at a time by the pawl on the pendulum (i.e. one tooth per second) and sprung contacts beside the index wheel are closed by the passing of the teeth on each right-to-left swing of the pendulum, thereby giving impulse via the electromagnet. A second set of contacts within the top part of the movement switch the current from a separate battery to the slave dials.
This drawing shows the maker's mark on this Brillie clock. It is stamped on a small brass plate screwed to the pendulum mounting bracket and has a serial number on the same plate. The lower signature of L.Brillie almost certainly refers to Lucien Brillie, one of the brothers in the Company, and I believe that C. Vigreux, along with Brillie, were the owners of the Brillie enterprise in Levallois-Perret.