Magdeburg hemispheres. Two dark brass hollow hemispheres which fit together, with bright brass handles projecting from the top of each hemisphere. One has a short handle, the other has a long handle with a valve.

ABDNP:200317a

Demonstration of the great power of air pressure. When the comparatively small hemispheres are evacuated they are very difficult to pull apart, requiring a foce exceeding 400 N. Thick-walled brass hemispheres with central rim; one handle post with 2 mm through hole. One sphere blind, one with air hole through handle leading to brass tap with detachable handle.

1790-1820

brass
internal diameter 80 mm; external diameter 105 mm; overall length 305 mm

Physical Object