Experiment with a Globe Freely Suspended in Water

Abstract

The Reverend Father Kaspar Schott recalls in his.Magica Universalis Naturae, part 3, Book V, section 19 “that Father Kircher at Rome with indefatigable enthusiasm and persistent concentration had devoted himself to finding a method for this type of suspension until he finally discovered it, as Kircher himself describes in his Magnes, Book II, part 1, preliminary explanation 5, method 3, page 157: “Take spring water or some other liquid cloudy with the usual impurities and purify it by boiling for a long time. Then fill a glass sphere half full with it. Add to this some other liquid of dissimilar ingredients derived from a mixture of wine, turpentine, olive oil, or a similar substance that does not mix well with the others and take care that it be of the same color as the liquid lying beneath it. (I myself usually add a tartaric solution to the wine spirits which do not mix.) Then when the container has been filled with such liquids, you will put a small magnetized sphere in it. I maintain that this small sphere, suspended at first on the surface of the liquids, will descend subsequently to the middle of the spherical container and will remain there. For since this sphere is heavier than the surface water and lighter than the lower water, it will descend to the surface of the lower water and will remain there because of its weight relative to the water. Thus the sphere will come to rest in the center of the container.