anything holding them. This of itself was strange
enough; but now the worthy burgomaster produced teams of horses, and
harnessing them to either side of the hemispheres, attempted to pull
the adhering brasses apart. Five, ten, fifteen teams--thirty horses,
in all--were attached; but pull and tug as they would they could not
separate the firmly clasped hemispheres. The enormous pressure of the
atmosphere had been most strikingly demonstrated.

But it is one thing to demonstrate, another to convince; and many of
the good people of Magdeburg shook their heads over this "devil's
contrivance," and predicted that Heaven would punish the Herr
Burgomaster, as indeed it had once by striking his house with lightning
and injuring some of his infernal contrivances. They predicted
his future punishment, but they did not molest him, for to his
fellow-citizens, who talked and laughed, drank and smoked with him, and
knew him for the honest citizen that he was, he did not seem bewitched
at all. And so he lived and worked and added other facts to science, and
his brass hemispheres were not destroyed by fanatical Inquisitors, but
are still preserved in the royal library at Berlin.

In his experiments with his air-pump he discovered many things regarding
the action of gases, among others, that animals cannot live in a vacuum.
He invented the anemoscope and the air-balance, and being thus enabled
to weight the air and note the changes that preceded storms and calms,
he was able still further to dumfound his wondering fellow-Magde-burgers
by more or less accurate predictions about the weather.

Von Guericke did not accept Gilbert's theory that the earth was a great
magnet, but in his experiments along lines similar to those pursued
by Gilbert, he not only invented the first electrical machine, but
discovered electrical attraction and repulsion. The electrical machine
which he invented consisted of a sphere of sulphur mounted on an iron
axis to imitate the rotation of the earth, and which, when rubbed,
manifested electrical reactions. When this globe was revolved and
stroked with the dry hand it was found that it attached to it "all sorts
of little fragments, like leaves of gold, silver, paper, etc." "Thus
this globe," he says, "when brought rather near drops of water causes
them to swell and puff up. It likewise attracts air, smoke, etc."(9)
Before the time of Guericke's demonstrations, Cabaeus had noted that
chaff leaped back from an "ele