The barometer was invented in the second half of 17th century. It is a scientific measuring device used in physics and meteorology to measure atmospheric pressure. It appeared in the French “bourgeois” households in the mid 18th century. It usually contains mercury, which must be handled with the utmost care, for it is noxious for human beings. Until the end of 19th century, it was made out of wood, glass, lead and mercury. The wooden part can be sculpted, painted, lacquered or even stuccoed. Louis XV, Louis XVI and Directoire period barometers are in high demand for their decoration, scarcity and finesse. With the new scientific discoveries in the 20th century, barometers improved. New kinds of instruments were invented, like metallic barometers. Master clock and watch makers such as Jaeger-leCoultre create many high quality barometers.