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42
The average is secured by assuming lOJ^ metal, neglecting the trollite
phase, which was from iron meteorites, and assuming that these
elements are not present in the silicate fraction and its trollite.
Our adopted atomic abundances are 1.00, 0,82 and 1,62 for Os,
Ir, £ind Ft, respectively. Qoldschmidt*s estimates are certainly
approximate, and the agreement is satisfactory. Data on these
elements, of the precision of the Goldbergs Uchiyama and Brown
(1951) data for Pd and Au would be highly desirable. The even and
odd mass curves, if they are smooth and if their slopes are
given by the isotopic abundances of Re^°^ and Re^"*^, Os^^7 and
Os-'-"^ ^ and Ir^^l and Ir °^ for the odd mass curve and mostly of
the Os^^^ and Os^90^ and Pt"^^^, Pt^^^^ and Pt"*"^ for the even
mass curve, must lie close together and have maxima at m.-isse8
193 and 194. These maxima are similar to those in tha neighborhood
of mass number 130.
We use Goldberg, Uchiyama and Brown's (1951) data for the
nickel-gold ratio in order to fix the atomic abundance of gold.
These analytical data have a rather wide spread of values for this
ratio with an average value of 5.8 x 10** by weight. Their palladiumgold
ratios are more nearly constant. With our nickel abundance
this gives 0,145 ^or the atomic abundance.
Mercury, thallium, lead, bismuth, uranium and thorium
Mercury is a volatile element which may have bean partly lost
from the meteorites. Also it is so prevalent in all ehemlcal
laboratories that all analyses are suspect. The Noddacks (1934)