The following is Helden's table of extant seventeenth century air pumps, the oldest of which being the pump made by Otto Guericke in 1663 for Johann Schonborn, now kept at the Deutsches Museum, Munich:
In existographies, Anne C. van Helden (c.1945-) is a Danish science historian, who in 1991 was associated with the Boerhaave Museum (see: Herman Boerhaave), in Leiden, noted for []“Guericke had designed his first air pump on the basis of a fire syringe: a piston moving back and forth in a brass cylinder. During the outward motion, it took in air from a spherical recipient. The pump was emptied during the inward stroke, while a leather valve prevented the air from flowing back to the recipient. The outlet was supplied with a valve as well, to prevent the atmospheric air from being taken in during the suction stroke. Hooke and Huygens improved on this design, but the overall idea remained the same. Leakage was the largest problem with the earliest vacuum pumps. To reduce it, the pump cylinder had to be perfectly straight with a smooth inner surface. Requirements like this made the construction of a vacuum pump extremely expensive and difficult. No more than fifteen scholars and institutions succeeded in obtaining a vacuum pump before 1670, and most of these depended on Guericke, Hooke, or Huygens for the construction and maintenance of their instruments.”— Anne Helden (2003), “Air Pump”, in: Encyclopedia of the Scientific Revolution [1]
