A copy (made in 1876) of a pair of large Magdeburg hemispheres used by the German physicist Otto von Guericke. Guericke (1602-1686) the inventor of the vacuum pump became famous due to an experiment he carried out in front of the Reichstag at Regensburg. During this experiment to demonstrate the effect of atmospheric presure, sixteen horses attempted and failed to pull apart the two halves of an evacuated sphere. These halves were known as the Magdeburg hemispheres after the town where Guericke was born.
© Science Museum / Science & Society Picture Library