Abstract

In July 1647 Valeriano Magni published in Warsaw a description of his experiment proving the existence of vacuum. His treatise called “Demonstratio ocularis, loci sine locato, corporis successive moti in vacuo, luminis nulli corpori inhaerentis” provoked a huge polemic, not only with the opponents of the void but also concerning the authorship of the experiment. The article deals with the circumstances of Magni’s experiment and the polemics with both scholars attacking Magni from the point of Aristotelianism and French scientists who admitted the existence of the void but accused Magni of plagiarism, for experiments with vacuums had been performed by Torricelli and Pascal first. The attention is paid to the philosophical background of Magni’s experiments.