Many explosions--large and small--reflect the interplay between the output of energy and the resistance from the density of the ambient medium. This balance is schematized by Taylor's scaling but the agreement with observations is rarely perfect. Correction factors close to 1 must be included. In this third episode on the physics of explosions we show that these corrections factors can be understood as special values of the Taylor-Sedov number, a dimensionless number well deserving of its own name.