A new, containerless method for measuring viscosity variations, as a f
unction, e.g., of temperature or concentration, is described. Relative
viscosities are extracted from the resonance quality factor near eige
nfrequencies of deformation modes of gas-film levitated liquid drops.
Both the geometrical aspect of the drop and the resonance profile are
dissymmetric in general. This can be understood in terms of a parametr
ic instability against nonlinear oscillations. The method could be use
ful for viscosity measurements under conditions where contact with wal
ls should be avoided-in particular at high temperatures, in order to a
void corrosion or chemical contamination.