This watch is the nicest Hampden I have had to date. The escapement is highly finished and includes radiused pallets. So it appears Cain was using these longe before the 16s Hamiltons. The staff and pallet arbor are very highly finished. The staff pivots are 13/100 mm. Gold balance screws as I would expect on a RRG; no timing screws and a flat balance spring. I was surprised to find a false plate with different serial number and an 1877 patent date. Also, you can see the mounts for the setting pinion have the correct batch number but the lower one is unfinished brass. I have seen pictures of other Hampdens with such features, including one private label. I am told the serial numbers match yet the barrel bridge is left in brass. Very curious but reveals something about early production maybe. In a similar vein, this Perry has a curious construction element in setting mechanism. If you look closely, you will see a screw set into the crown screw for the rocking setting lever. The crown screw is threaded for this screw; which is a grub screw that locks into a hole in the pillar plate. It basses thought the crown core. I am unsure of its purpose, but I can think of two. One is to set the proper endshake for the core, the other is to prevent the crown screw form unthreading in use. A photo shows the Perry pillar plate next to a later Hampden for comparison. This watch retained its Hampden dust band! First one I saw.