Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/128

 circle, or in the ellipis, if the forces are directed to the centre of the figure placed in the abcia, thoe forces by increaing or diminihing the ordinates in any given ratio, or even by changing the angle of the inclination of the ordinates to the abcia, are always augmented or diminihed in the ratio of the ditances from the centre; provided the periodic times remain equal; o alo in all figures whatoever, if the ordinates are augmented or diminihed in any given ratio, or their inclination is any way changed, the periodic time remaining the ame); the forces directed to any centre placed in the abcia, are in the everal ordinates augmented or diminihed in the ratio of the ditances from the centre.