56 GREAT MEN OF SCIENCE 



until 1660, he was almost continuously occupied in the 

 business of the town, and travelled a great deal to Vienna, 

 Prague, Regensburg, to the heads of states, princes, and state 

 assemblies, with the object of regaining the ancient rights of 

 Magdeburg. Nevertheless he again and again found time in 

 this period of his life to devote himself to the prosecution of 

 his desire for deeper knowledge of nature. Above all, he was 

 greatly interested in the uncertainty, much discussed at the 

 time, as to whether it was possible or impossible to produce 

 an empty space, whereby it appears that Toricelli's experi- 

 ments, now some years old, must have been known among the 

 learned, but not sufficiently in other directions, particularly 

 in Germany, which, at the close of the Thirty Years War 

 (1648), was for the most part laid in ruins, and deprived of all 

 peaceful civil life. 



Guericke set about using his best efforts to make possible 

 the production of an empty space whenever desired, if such a 

 thing could be done. He attempted to use for this purpose 

 the ordinary well or fire-engine pump, and since this was 

 made for pumping water, he connected one to a cask full of 

 water and otherwise completely sealed up, in order to see 

 whether on pumping out the water an empty space would 

 remain in the cask. The power necessary to work the pump 

 turned out to be so great that he was first obliged to reinforce 

 all joints and fastenings. When finally three strong men 

 working the pump were actually able to pump out the water, 

 a noise was heard in all parts of the cask, as if the water was 

 boiling furiously, and this lasted until the whole cask was 

 filled with air in place of the water removed. Obviously, 

 wood was not sufficiently airtight for such experiments. 

 When the experiment had been repeated fairly satisfactorily 

 with a cask submerged in water, Guericke had a large copper 

 sphere made, which could be attached to the pump, and he 

 now proceeded to omit the water and pump out the air 

 directly, which was entirely successful. As soon as it was 



