In mechanical horology, a remontoire, (from the French remonter, meaning ‘to wind’) is a small secondary source of power, a weight or spring, which runs the timekeeping mechanism and is itself periodically rewound by the timepiece’s main power source, such as a mainspring. It was used in precision clocks and watches to place the source of power closer to the escapement, thereby increasing the accuracy by evening out variations in drive force caused by unevenness of the friction in the geartrain. In spring-driven precision clocks a gravity remontoire is often used to replace the uneven force delivered by the mainspring running down by the more constant force of gravity acting on a weight. In turret clocks it serves to separate the large forces needed to drive the hands from the modest forces needed to drive the escapement which keeps the pendulum swinging. A remontoire should not be confused with a maintaining power spring, which is used only to keep the timepiece going while it is being wound. source wikipedia.
*The stamp is called a hallmark, and is intended to show how much silver is contained in the item. 825 silver means that the item is made up of 82.5% silver and 17.5% other metals (often nickel or aluminum). 825 silver is a very odd number. Are you sure you are reading it correctly? 925 silver is called “sterling silver.” If it is indeed 825, you may have an antique piece that originated in Europe (usually Germany) in the mid-1800s. source Ask.com