Florentine Experiment, The, was to determine whether water was compressible to any appreciable extent. It was performed in Florence by Torricelli, in the year 1661, and from the result was deduced the fact that water is incompressible. Later experiment has shown this conclusion to be incorrect, for water does admit of a certain amount of compression, and instruments have been designed to measure this amount. The Florentine experiment consisted in filling a hollow sphere of gold with water, plugging up the orifice by means of which the filling was effected, and then submitting the sphere to great external pressure. It was a known fact that of all solids with given surface area the sphere possesses the greatest volume, and it was therefore recognised that if the golden sphere should undergo any deformation into an ellipsoidal form, its bulk and, therefore, that of the enclosed water would be diminished. The actual result was that rather than submit to any appreciable diminution, the liquid forced its way through the pores of the metal, and appeared as dew on the outside. Francis Bacon had performed the same experiment with a leaden sphere some twenty years earlier.