giovanni ceva also studied applications of mechanics and statics to geometric systems. at one point, however, he incorrectly resolved that the periods of oscillation of two pendulums were in the same ratio as their lengths, but he later realized and corrected the error. ceva also worked on hydraulics. in 1728, he published "opus hydrostaticum" which discusses his work in hydraulics. in fact, he used his knowledge of hydraulics to stop a project from diverting the river reno into the river po.