Emotional pressure

The concept of pressure was preceded by some emotive terminology: the Flemish mathematician and engineer, Stevin referred to the ‘violence’ water can inflict and Pascal described the ‘suffering’ of walls of a container. Stevin is credited with proposing the concept of the parallelogram of forces (the concept of the resolution of velocities is found in the work of Aristotle). Stevin is notable also for proposing that objects of different mass accelerate at the same rate, two years before Galileo, and for carrying out an experiment in which a one-pound and a ten-pound lead ball were dropped thirty feet and the time of their impact judged by the sound of their collision with the floor. Stevin is credited with the design of a land yacht, which contemporary accounts report carried up to 28 people and covered 97 km in less than two hours, faster than any other vehicle of the time.