  The CMB data recently released by BOOMERANG and MAXIMA suggest that the
anisotropy spectrum has a third peak in the range 800<l_3<900. A combination of
this result with constraints from large-scale structure permit us to
differentiate between different quintessence models. In particular, we find
that inverse power law models with power \alpha >1 are disfavoured. Models with
more than 5% quintessence before last scattering require a spectral index
greater than 1. These constraints are compared with supernovae observations. We
also show that the CMB alone now provides strong evidence for an accelerating
universe.
