from the central nucleus, at the rate which we know at the
surface from a central nucleus of anything like 0.4 the radius
of the earth, would give a shrinkage of anything like the
amount indicated by the mountain ranges, in anything like the
time which we are led to assign on other grounds to the
geologic periods?

Rudski has also attempted to connect the shrinkage and age of
the earth. Both these methods depend on how fast the earth is
losing heat, that is on the geothermal gradient. Since at
present, owing to the apparently large but unknown contribution
of radioactivity to that gradient we know very little about
what the other portion is, it seems unwise to give any figures,
especially as almost all the numerical data are largely guess
work. It will, however, be fair to say that very long times for
the age of the earth seem to be indicated, nearer millions of
millions than millions unless the radius of the gaseous core
was mainly small or its rate of contraction with loss of
temperature high.



THE CASH VALUE OF SCIENTIFIC RESEARCH

BY PROFESSOR T. BRAILSFORD ROBERTSON

UNIVERSITY OF CALIFORNIA

THERE can be no doubt that the average man and woman in Europe
and America to-day professes a more or less nebulous feeling of