The Barraud Dynasty / Barraud karrusel - 3/4498
Barraud's version of Bonniksen's Karrussel, 3/4498, is the standard 52 1/2 minute movement with the subsidiary seconds bit. This example is free sprung with a gold 4th wheel (and perhaps other wheels). It is about 20 size and has nicely blued steel parts including the escape wheel. See the center seconds Karrussel for an example of the 37 minute movement that is driven from the 4th wheel rather than the 3rd wheel.
The b date letter is for 1897/1898. That date is clearly appropriate for a Bonniksen watch, The B grade half chronometer in the collection carries the c date letter for 1898/1899 and has serial number 3/3874. I originally thought the date letter on that watch was the large C for 1878/1879 but the makers mark and shield form confirm the 1898/1899 date. Having the serial numbers out of order by 600 is likely due to the range of suppliers to the firm at that time.