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18
million times smaller than that of the group of the next heavier
elements in the cosmos, carbon, oxygen, and nitrogen. According
to Qreenstein and Richardson (195I), Li in the sun seems to be
even less abundant by another factor of 100. The low abundance of
these three elements can easily be understood as a consequence
of their instability at high stellar temperatures and their
possible thermonuclear reactions with protons. Such reactions
may have occurred toward the end of the processes by which the
elements were made.
The analyses of igneous rocks and of meteorites for these
elements are summarized by Qoldschmidt (1937)» He gives for
the atomic ratios of Li and Be in the llthosphere and in silicate
meteorites relative to Si equal to 10"s
Li
Be
Llthosphere 900 67
Silicate meteorites 100 20
Both are concentrated to some extent by the fusion pi^ocesses that
have concentrated elements in the earth's crust. For this
reason smaller values than those of the meteorites. Just as in the
case of K, U, and Th, might be used in our estimate of cosmic
abundances. However, because of the uncertainty of analyses, no
corrections have been made. Qoldschmidt estimates the atomic
abundance of boron as 28. Its abundance in the earth's surface
is complicated by its appreciable concentrations In the sediments
and ocean waters.