Nothing Schatten (1974) has said causes me to alter any of the earlier criticisms of Schatten (1973) made in Gilman (1974). However, I am compelled to respond additionally to his response as follows:
First, Schatten (1974) is incorrect in saying that in Gilman (1972) I proposed the "Earth's Rossby waves" as a mechanism for driving solar differential rotation. Also, giant cell convection is not simply "a solar analogy of an earthly phenomenon." The motions modelled in Gilman (1972) are in fact global scale convection cells centered at the equator, which are of global scale only in a deep layer of fluid such as the Sun's convection zone. There is little evidence they occur in a thin atmosphere such as the Earth's where, even if they did, they would be confined to within a few miles of the equator, and would have little influence on its global circulation.
Second, the formula r/= ~v, where q is the dynamic viscosity, ~ the fluid density and v the kinematic viscosity, which Schatten (1974) says does not apply in a highly conducting fluid, is, in fact, simply the definition of the relation between the two viscosities. The real point is whether v or q can be estimated for a turbulent fluid such as the solar convection zone from mixing length theory or, more generally, from turbulence theory. Using mixing length formulae and arguments himself, Schatten (1973) grossly underestimated v, as I argued in my response. In that paper, he does not invoke electromagnetic forces to reduce its magnitude. The work of Shercliff and Hughes and Young which Schatten (1974) refers to really applies only to steady laminar flow, whereas the solar convection zone is turbulent and quite unsteady. The point of Shercliff's example is that the fluid can behave quite differently when the magnetic energy density is as large as the kinetic energy density from when magnetic energy density is small by comparison, On the surface of the Sun, however, magnetic energy is as large or larger than kinetic energy density only in isolated areas, such as in sunspots, and magnetic knots, which cover only a small fraction of the solar surface. It is true that many of the knots may be at the vertices of supergranules cells but these cells are continually reforming and decaying in new patterns, which process by itself will provide mixing and transport of momentum and of magnetic flux (the latter being Leighton's 'random walk'). Under the conditions prevailing on the Sun, any inhibiting effect of the magnetic field on momentum mixing could never reduce such mixing by several orders of magnitude, as Schatten requires.