Volume of Gabriel's Horn/Historical Note

Historical Note to the Volume of Gabriel's Horn
The volume of Gabriel's horn was first demonstrated by in $1643$.

The result caused great astonishment at the time, as it was the first example of a solid figure demonstrated to be of infinite extent while also having finite volume.

As put it:
 * To understand this for sense, it is not required that a man should be a geometrician or a logician, but that he should be mad.