The unit of viscosity is a poise 1 gm cm-1 s-1 = 10-1 kg m-1 s-1.
To measure viscosity, one must determine flow in the presence of a velocity gradient.
Poiseuille2 derived a formula for the volume, ∆V, of an incompressible fluid of viscosity,
η, moved through a tube of length l and radius, r, in a time, ∆t, subject to a pressure drop, ∆P, Eq. (5.2).3