Vasily Borisov

From the technological viewpoint, it seems surprising that the air pump, similar as it was in construction to the water pump, was invented two thousand years later than its predecessor. This lag is even more amazing, provided that the Hellenic technicians were already close to developing an air pump, as is evident from the description of devices based on air compression and rarefaction, provided by Heronis Alexandrini in his treatise “Pneumatics.” The paper argues that the medieval artisans were, indeed, aware of some properties of the rarified air and took them into account when constructing devices for pumping water. According to the author, it is the power of such dogmas as “Natura abhorret vacuum” and “Emptiness can be created only by the almighty God” that hampered the invention of the vacuum pump for so long. As is shown in the paper, the work of Otto von Guerike resulting in this invention was influenced primarily by G. Berti and E. Maniano, whose experiments with a water barometric pipe became widely known in Europe. Using present-day methods of vacuum evaluation, the author has concluded that the ultimate vacuum of the first mechanical pumps was about 25 mm Hg. The development of mercurial piston pumps in the 19th century made it possible to attain pressures lower than 10^-2mm Hg.