Geoscience Reference
In-Depth Information
this rainwater would allow him to quantify the volume of sodium in
the oceans from this source. While demonstrating how his rain-gauge
would operate in theory, there is no evidence to suggest that he
actually built it, or, if so, that he put it to effective use. He also
examined the rate of solution of various igneous materials in fresh
and salt water and showed that of the four tested (basalt, orthoclase,
obsidian and hornblende) the basalt from the Giant's Causeway in
County Antrim dissolved more readily than the others, and that salt
water was a more effective solvent than fresh water. Not surprisingly
the obsidian, a volcanic glass, proved the most resistant to solution.
Joly noted that his results for the rates of denudation were far lower
than those demonstrated by field study and argued that additional
factors such as organic acids, wetting and drying, and other erosive
processes were more important than solution of rocks by water.
Nevertheless he made an allowance for the solvent action of the
ocean by reducing his age estimate by a few million years to
96 million.
After the initial peak of interest that followed closely from his
1899 paper, many of Joly's subsequent papers on the subject were
simply reports of lectures or reiterations of the original theory. In
1915 with the publication of Joly's series of essays Birth-time of the
World, which included readable and entertaining pieces on the colours
of Alpine flowers and on skating, as well as a exposition on the
antiquity of the Earth, there followed short-term, renewed interest
in the sodium method - but this interest did not last. The theory
was finally consigned to the scientific scrap-heap by several leading
geologists on both sides of the Atlantic, such as the petrologist Alfred
Harker (1859-1939) in 1914, JohnWalter Gregory (1864-1932) in 1921,
Arthur Holmes (1890-1965) in 1926 in Britain, and Joseph Barrell in
1917 and Thomas Chrowder Chamberlin in 1922 in the United States.
In damning words, Holmes rejected it as 'worthless'. Earlier in 1913
Holmes had cogently reasoned that the rocks undergoing erosion
would have had to lose more sodium into the oceans than they ever
contained for Joly's figures to add up. Holmes and Chamberlin, as will
