The Measurement of Geological Time

Abstract

TWENTY-FIVE years ago, opinions as to the scale of geological time were still in a chaotic state. The earlier controversy between Kelvin and the geologists had come to a dramatic end in 1906 with the discovery by Strutt (the present Lord Rayleigh) of the widespread distribution of radioactive elements through the rocks of the earth's crust. The earth could no longer be regarded as a spendthrift living on a limited capital of ancestral heat. An independent source of income had been disclosed in the energy liberated during radioactive disintegration, and henceforth no thermal argument could set a limit to the age of the earth.