“…In this region a new stretched variable, say (r -1)/ X(Re,e), is defined, in which X(Re,e) is chosen in such a way that the stresses at the interface are balanced, at least to first order. The interfacial stress balance is established by requiring the surface tension force to equal the net force associated with the stress distributions on both sides of the interface [see, for example, Wasserman and Slattery (1964)]. This will include the mean curvature of the interface, which is, in the present case, a nonlinear function in F"(£), F'(£), and F(£); F(£) is the value of r at the interface, namely, the unknown shape of the interface.…”