Otto von Guericke, German inventor, engineer and physicist, 1672. Portrait from his Eperimenta Nova, ut vocant, Magdeburgica, de vacuo Spatio (New Magdeburgian Experiments, as they are called, relating to a Vacuum), (Amsterdam, 1672), in which he published details of his invention of the air pump (1650), and his experiments on the power of air pressure. In the most famous of these, he used an air-pump to remove the air from between two large close-fitting copper hemispheres, known as Magdeburg hemispheres. The effect of the air pressure on the two hemispheres was such that two teams of 8 horses could not separate them. Once the air was let back into the enclosure, however, the hemispheres were parted easily.
