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We show that the Einstein-Straus model does not give a robust answer to the problem of the influence of the cosmic expansion on the local physics. This is done by finding the most general static region embeddable in a Friedmann-Lemaître-Robertson-Walker expanding cosmology and showing that the model must be 'almost spherically symmetric'. More precisely, we show that the boundary of the static region must be a 2-sphere at each instant of cosmic time. The motion of this 2-sphere in spacetime is as follows: its 'would-be' centre (if there were no static region) moves along a path whose projection on any 3space of constant cosmic time is a geodesic with respect to the induced 3-metric. The velocity of this geodesic is determined from the matching. In particular, this centre must be at rest with respect to the cosmological flow (thus giving a spherically symmetric model) when any of the standard energy-momentum tensors inside the static region is imposed.

The Townsend first ionisation coefficient X /~Z O and the total secondary coefficient YT have been measured for nitrogen and methane mixtures by the steady-state Townsend method for 4O,

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A mass spectrometer data processing system is described in which digitized isotopic information is fed on-line to a time-sharing, general purpose computer. A computational programme applicable to many isotopic problems requiring accurate peak selection is outlined.