Detailed Summary :-This is a HUGE and RARE SPLIT SECONDS FLYBACK or RATTRAPANTE Pocket Watch in 18K SOLID GOLD by the fine makers AGASSIZ dating from c1890 and weighing in at a MASSIVE 157 grammes. It is in perfect working order with all elements working and acting as they should.The MASSIVE 18K Solid Yellow Gold case is unsigned. It is solid 18 K Gold throughout and stamped as such inside the back cover and cuvette. It has a hinged front cover ( no dings or dents ) which is opened to reveal the pull out setting lever between 1 and 2. The case band is ribbed ( minor depression at 9 ). The case back is engine turned with a central cartouche ( no initials ) and is hinged. There are some minor depressions in the case back which would probably roll if desired and some smoothing to the engine turning due to age ( over 100 years old and 18 K Solid Gold so this is to be expected ). The cuvette is hinged and polished. All hinges are firm, all covers open and close as they should. The bow is firm. Massive heavy case, 54.4 mm diameter and 77.4 mm from the base of the case to the top of the bow. The case overall is in excellent condition and the assembled watch, case, movement, dial, crystal weigh a massive 157 grammes. ( Note that there appears to have been a crystal over the movement at some point as there is a bezel under the rear cuvette. It didn't have one when I bought it but you could reinstate it if you wish ).The CENTRE SPLIT SECONDS FLYBACK CHRONOGRAPH MOVEMENT is signed Agassiz, nickel finished and damaskeened. Gilded gear train. A mixture of nickel finished and polished steel flyback work. The fine and complex regulator is of Patek ' Snail Micrometer ' type. The fine moustache lever movement is in perfect working order, wound by the crown, set by the lever between 1 and 2 and winds, sets and ticks away without any encouragement. Flyback operated by pressing the crown, split by the gold button at 2 in the band , stopped by pressing the crown again, the hands join again by a further press of the button at 2 and stop and reset with the crown being pressed once more. All elements of the watch work as they should. Timekeeping and reliability are not warrantied as it is over 100 years old ( it does however keep excellent time ).The white enamel dial is signed Agassiz in black and has black Arabic hour markers with red outer 5 second markers divided into fifths for the split seconds. The seconds subsidiary as at 6. All hands are fine blued steel and in excellent condition. No cracks or chips in the dial which is in overall excellent original condition.The crystal is bevelled edge, possibly original and in excellent condition.Split seconds chronographs by Agassiz are rare. Examples in massive SOLID 18 K Gold cases are rarer still .... this one weighs in at 157 grammes. Don't miss out. I am a longstanding collector of fine watches, but nowadays concentrate my time on my Gundogs and only occasionally offer watches for sale. I have owned this particular watch for some years and it is in the same original condition as when I bought it. Any questions, please ask......PLEASE NOTE THESE IMPORTANT PAYMENT TERMS :-Payment is expected within 14 days of auction close unless we have agreed to extend this period. Failure to pay within this time will result in the item being relisted and a non paying bidder alert being filed.  If you live outside of the UK and the value of your purchase exceeds £250 GBP, then you must pay by Bank Wire, Bank Transfer or direct payment into my UK Bank Account.......You should also note that even though companies will sell you insurance for mail / parcel services, they will not honour it if the item is made in whole or part from precious metal which this is. Postage etc :- I pack and send watches very carefully when sending by Post, but if you would like to collect it in person you can. I can also deliver by hand subject to separate arrangement.