Photograph of Askania Z-beam torsion balance

Photograph of a Z-beamtype torsion balance designed by Loránd Eötvös in the late 19th century / early 20th century. This photograph taken and supplied by the instrument's maker Askania-Werke, which were based in Berlin.

This gravity pendulum apparatus is a later variation of a design from Austro-Hungarian general major, geophysicist and astronomer, Robert von Sterneck, and was built by renowned German instrument makers Askania.

The device worked by measuring coincidences between the movement of the swinging pendulums, and the chronometer, which would change depending on the specific gravity the pendulum was experiencing, allowing for a calculation of both the varying density and varying gravity of the earth's crust and tectonic plates.

von Sterneck used this design of gravity pendulum during the late 19th century to measure the density and interior structure of the earth by deploying these instruments in mines. This particular design shown in the photo has had modifications and improvements which allowed more accurate measurements to be made using all four of its moving pendulums.