13 - Melchior Pendulum
Made in 1960 in Brussels (Belgium).
- inclinometer constructed on the horizontal pendulum principle
period 20-40s - the pendulum is made of melted quartz
- optical recording by mirror on photopaper
Long period inclinometers study variations in the ground's inclination (dip) due in part to earth tides. The necessary thermal stability is ensured by using quartz, which dilates very little in heat, and by installation in mine pits where the temperature doesn't vary much. A Melchior pendulum was used in the Bussang tunnels in the Vosges mountains and in Sainte-Marie-aux-Mines (Haut-Rhin, Alsace).
