The use of fibre spinning and related experiments is examined and the
presentation of results in terms of a ''spinning viscosity'' is propos
ed. A re-examination of results for convected Maxwell and Jeffreys mod
els and FENE dumbbell models shows the importance of the flow history
prior to the spinning. Some undesirable ways of treating data are disc
ussed. Out of this comes a discussion of the appropriateness of using
viscosity or modulus as a measure of a material response and of using
rate of strain or strain as a variable. The work is theoretical, but l
eads to a proposal for testing the ways in which experimental data are
treated. A definition of a ''spinning viscosity'' is offered, and the
idea that one should only obtain one value from one spinning experime
nt is emphasized.