Otto von Guericke (1602-1686)

This detailed engraving shows that two teams of horses are not able to separate a sphere from which the air has been pumped. The large rimmed copper Magdeburg hemispheres were designed by German scientist Otto von Guericke to demonstrate the power of atmospheric pressure through the air pump that he had invented in 1656. When the rims were sealed and the air was pumped out, the sphere formed a vacuum and the two halves could not be separated until the pressure was equilibrated. The first artificial vacuum had been produced a few years earlier by Evangelista Torricelli, and had inspired Guericke to design the world’s first vacuum pump.

Also shown is a reproduction of the title page of this work illustrating the vacuum pump in the laboratory. This demonstration became popular in physics laboratories as an illustration of the power of air pressure.