  We show that recent measurements of the power spectrum of cosmic microwave
background anisotropies by BOOMERanG and MAXIMA can be characterized by four
observables, the position of the first acoustic peak l_1= 206 pm 6, the height
of the first peak relative to COBE normalization H_1= 7.6 pm 1.4, the height of
the second peak relative to the first H_2 = 0.38 pm 0.04, and the height of the
third peak relative to the first H_3 = 0.43 pm 0.07. This phenomenological
representation of the measurements complements more detailed likelihood
analyses in multidimensional parameter space, clarifying the dependence on
prior assumptions and the specific aspects of the data leading to the
constraints. We illustrate their use in the flat LCDM family of models, where
we find Omega_m h^{3.8} > 0.079 (or nearly equivalently, the age of the
universe t_0 < 13-14 Gyr) from l_1 and a baryon density Omega_b h^2 > 0.019, a
matter density Omega_m h^2 < 0.42 and tilt n>0.85 from the peak heights (95%
CL). With the aid of several external constraints, notably nucleosynthesis, the
age of the universe and the cluster abundance and baryon fraction, we construct
the allowed region in the (Omega_m,h) plane; it points to high h (0.6< h < 0.9)
and moderate Omega_m (0.25 < Omega_m < 0.6).
