Geoscience Reference
In-Depth Information
river discharge of sodium, and also queried the effects of geothermal
cooling over time. Joly also delivered a paper to the same meeting, and
his conclusions on the sodiummethod and its use in dating the Earth
must have created quite a stir as his report was ordered by the General
Committee to be published in extenso. Later papers by Sollas in 1909,
by Becker in 1910 and Frank Wigglesworth Clarke (1883-1931), the
chief chemist to the United States Geological Survey, in the same year
laid minor criticisms at Joly's door. Sollas recalculated the annual
discharge of the rivers from which he derived a date of 78 million
years, but suggested the age of the Earth lay within the range 80-150
million years. Clarke, whose important work was in the compilation
of extensive volumes of geochemical data, examined the rate of
removal of sodium from the landmass and arrived at a figure of 80
million years, while Becker suggested that Joly's figure of 10% for the
contribution of sodium recycled from the atmosphere was too high
and that the volume was closer to 6%.
Joly's responses to the reviews of his work strongly reinforced
his uniformitarian principle. However, he did accept that his estimate
of the role of rainwater in providing sodium chloride might have been
overestimated and might require further experimental work.
With respect to fossil seawater, Joly stated that it could only have
contributed 0.9% of oceanic sodium chloride and, as such, was
negligible. His response to Sollas was that 'there is much reason to
believe that the nineteen rivers ... afford an approximation as to what
the world's rivers yield'. Indeed, he stated in 1911 that the findings of
Sollas, Becker and Clarke, together with his own, gave concurrent
results of circa 100 million years, and proudly anticipated that this
determination would not be 'seriously challenged in the future'.
Joly went further in defence of his ideas in that he devised
various experiments which he hoped would generate acceptance of
some of the theoretical assumptions made in his 1899 paper. In one of
these he devised a fractionating rain-gauge, which he hoped would
allow him to collect rainwater over incremental time periods.
Subsequent analysis of the amount of dissolved sodium chloride in
