ABSTRACT
The perplexities raised at the beginning of the seventeenth century by the Galileian laws indicated fairly clearly to one that the case of harmonic pendular motion could be a situation in which the hypothesis just suggested might be tested experimentally. Among the most incredible discoveries made by Galileo in the course of his mechanical investigations, is that of the laws of the harmonic motion of the pendulum. The experiments that will be described in the coming pages were designed to ascertain the existence of well-defined relations between the perception of proper pendular motion and the presence of a number of factors that can act upon it. Inclined planes between vertical and horizontal, taken together, define only one class of motions: those directed downward. A slot is cut out of the screen along the side of the figure that represents the inclined plane, in order to transform the circular motion of the spiral into a linear motion of a small square.
