Key points are not available for this paper at this time.
The natural isotopic abundances of the following elements have been determined by mass spectrometric techniques: Different masses were focused by variation of the magnetic flux in Nier-type, 60^ mass spectrometers. Ion currents were measured potentiometrically. Each measurement represents at least 15 determinations. Many measurements are averages of series with different spectrometers and ion sources. From available packing fraction data and these abundances the chemical atomic weights have been computed.
White et al. (1948) studied this question.