““The new law that he predicted seemed to defy common sense. It was that the viscosity of a gas-the internal frictional that causes drag on a body moved through it-is independent of its pressure. One might expect a more compressed gas to exert a greater drag; even James was surprised at first that the theory said otherwise. But further thought showed that, at higher pressure, the effect on a moving body of being surrounded by more molecules is exactly counteracted by the screening effect they provide: each molecule travels, on average, a shorter distance before it collides with another one. A few years later, James and Katherine themselves did the experiment which showed the prediction to be correct.””
