Hello, I have been reading everything I can find.
the age is correct, as style of hourglass you have is consistent to early 19th century (1800's)
I am having trouble with finding when orange colored mercury came into being and how they did that. I have no way of knowing who made the piece without any marks; However, I am looking at the orange mercury now and trying to find out where that came to be. From a castle in France I have no way to prove if there was no written providence given to you stating that. I am still working on this and will post as find things through the evening.
I found the following history of the hourglass:
It has long been thought that hourglasses were certainly an ancient device, thanks especially to an ancient Roman bas-relief that seemed to include one. Recently, however, it was determined that the part of the bas-relief with the hourglass on it was only added in the 16th century.
In fact, the first authentic evidence of hourglasses did not appear until 1338 AD, when Ambrosio Lorenzetti painted a fresco with the personification of Temperance holding an hourglass (image 4). Later that century, hourglasses were mentioned in written documents, including a 1345 sales receipt for items bought by the clerk of an English ship, and the inventory taken at the 1380 death of King Charles V of France. So from these three examples, it is clear that by the early 14th century, hourglasses were in common usage by everyone from sailors to kings, and had already taken on symbolic values as a device of measurement.
It makes sense that a ship clerk would have purchased an hourglass, since it is a strong possibility that hourglasses were first developed for maritime use (image 5). Before the 14th century, time was measured in unequal hours, based on the durations of day and night on each date. On a ship, however, the measurement of equal hours would have been necessary for calculating the distance traveled (since distance = rate x time). Sand-filled hourglasses would have been preferable to water clocks (the most ancient form of clock, which functions similarly to the hourglass) because, if suspended, they would be relatively unaffected by the motion of the ocean.
So basically all the evidence points to the hourglass being invented around 1000-1100 AD, during that era's great advances in maritime navigation. This dating gives the hourglass roughly enough time to become widely used and to enter the material record around 1300.
The part of history on hour glassses came from this link below.