HartmutIt can't be an alarm since the isn't an extra hand to set the alarm time. If it isn't a repeater, it should be a sonnerie. I would still stay well away since there appear to be parts defective or missing and replacing them on a movement that old yet that complicated will quickly become very expensive.
HartmutNo, that's not really what I meant. In the absence of any alarm hand, dial (or even movement) side, I am confused about how the owner would know even remotely when the thing would go off once set.
ThanksNice pic Adam ! There is a cam on the underside of the indicating wheel . It has a notch that coincides with the hand , the two halfs of the wheel turn together when the cam meets the beak , it releases the hammer ( at the lower left hand side of the photo )