The Florentine Accademia conducted intense experimentation on the physics of air, conceiving and building the earliest models of the barometer and hygrometer. It also conducted a number of ingenious experiments devised to demonstrate that a vacuum can be produced in nature. In its sessions, astronomical questions, most notably about the true structure of Saturn, were hotly debated, making use of advanced telescopic instrumentation. Through a series of original experiments, consisting of violently striking hollow metal spheres filled with water, the members of the Accademia demonstrated the incompressibility of fluids.