Koziel's results on the librations have been rediscussed. Some serious departures from independence of the errors were detected and have been allowed for. The results are

β = 0.0006271 ± 0.0000010

γ = 0.0002362 ± 0.0000082

These do not differ much from Koziel's values but the uncertainties are larger. Both are consistent with results previously derived by comparison of results of different authors, and γ is consistent with a reinterpretation of a result of Yakovkin.

The effect of elasticity is considered. It is shown that the elastic strain does not contribute to the librations but would affect the perturbations of a satellite. Allowance for this difference reduces Michael's estimate of 0.4015 for C/Ma2 to 0.4001 ± 0.0030, which would be consistent with either uniform density or with the value I found in 1936 after allowance for compressibility and a possible thin surface layer, namely 0.3971 ± 0.0007.