Vacuum engineering
Vacuum technology is a method used to evacuate air from a closed volume by creating a pressure differential from the closed volume to some vent, the ultimate vent being the open atmosphere. When using an industrial vacuum system, a vacuum pump or generator creates this pressure differential. A variety of technical inventions were created based on the idea of vacuum discovered during the 17th century. These range from vacuum generation pumps to X-ray tubes, which were later introduced to the medical field for use as sources of X-ray radiation. The vacuum environment has come to play an important role in scientific research as new discoveries are being made by looking back to the basic fundamentals of pressure. The idea of “perfect vacuum” cannot be realized, but very nearly approximated by the technological discoveries of the early 20th century. Vacuum engineering today uses a range of different material, from aluminum to zirconium and just about everything in between. There may be the popular belief that vacuum technology deals only with valves, flanges, and other vacuum components, but novel scientific discoveries are often made with the assistance of these traditional vacuum technologies, especially in the realm of high-tech. Vacuum engineering is used for compound semiconductors, power devices, memory logic, and photovoltaics.
Otto von Guericke
Stimulated by the interest taken in his work, von Guericke was scientifically very active in the decade after 1654. In June 1656 we find him writing to Fr. Schott ("Mechanica Hydraulico-pneumatica", p. 444) "Since the time when I produced the exhibition for the said eminent Elector, I have a better and clearer grasp of all these matters and many other topics as well." The celebrated hemispheres experiment was, as noted in the biographical section above, carried out between July 1656 and August 1657. In Chapter IV of Book III he describes a new and much improved design of vacuum pump and attributes its invention to the need for a more easily transportable machine with which he could demonstrate his experiments to Frederick William, who had expressed the desire to see them. The new pump is also described on p. 67 of the "Technica Curiosa". The demonstration in the Elector's Library at Cölln an der Spree took place in November 1663 and was recorded by a tutor to the Elector's sons. (Schneider p. 113.) A number of experiments, such as the rather cruel testing of the effect of a vacuum on birds and fish ("Experimenta Nova", Book III, Chapter XVI), are not described in the "Technica Curiosa". Although the "Experimenta Nova" does contain correspondence from 1665, there is no reason to doubt von Guericke's assertion that the work was essentially finished by March 1663.