There is nothing particularly special about this movement, I would just be interested to know who made it.
The bottom plate is 42mm diameter, so it's about 18.6 lignes, which seems a funny size. I don't know whether movements were actually made in lignes, I would guess that they were probably made in metric sizes using millimetre tools and gauges, and then named to the nearest ligne out of convention?
Swiss lever escapement with cut bimetallic balance with timing screws and Breguet overcoil balance spring but no shock protection. Jewelled to the centre wheel. So it's quite nicely made, but it's the shape of that big bridge that holds the centre, third and fourth wheel that is most distinctive. It should be easy to identify from that but I don't recognise it - I don't have enough experience to just identify it by eye, I'm hoping someone here will.
Thanks for any help or comments!
Regards - David