Geoscience Reference
In-Depth Information
a Scottish naturalist, in the 1880s in the Scottish Geographical
Magazine. Murray focused on 19 rivers, including the Amazon, and
calculated the annual volume of water and mass of various mineral
salts and other materials carried by them into the oceans. Using
results from the celebrated oceanographic expedition of HMS
Challenger, Joly noted that the oceans contained 3.5% by mass of
various salts of which sodium chloride [NaCl] (35,990
10
12
tons),
magnesium chloride [MgCl
2
] (5,034
10
12
tons) and magnesium
sulphate [MgSO
4
] (2,192
10
12
tons) were the most abundant.
Sodium constitutes just under 40% of sodium chloride, which meant
that the mass of the element in the oceans was 14,151
10
12
tons.
However, the rivers carry not only sodium chloride, but also lesser
volumes of sodium sulphate [NaSO
4
], sodium nitrate [NaNO
3
] and
sodium chloride [NaCl], which Joly showed, based on Murray's
figures, contributed 157,267,544 tons of sodium annually into the
oceans. When he put these figures into the equation above he got:
14
;
151
;
000
;
000
;
000
;
000
157
;
267
;
544
tons per year
tons
ΒΌ
90
;
000
;
000
years
He concluded therefore that the age of the Earth was approximately
90 million years. With minor adjustments he widened this date to
between 90 and 100 million years.
Reaction to Joly's paper began to appear in the scientific press
within six months of its publication. Review articles were published
in several journals, including the American Journal of Science, Nature
and the Geological Magazine. Over the next decade a considerable
number of papers discussed Joly's sodium method, and reaction was
somewhat polarised: some authors were in broad agreement with his
ideas, whereas others raised a number of objections. The Reverend
Osmund Fisher penned the review that appeared in the Geological
Magazine, and it was by far the most testing. Fisher was a combative
character but well respected both as a geophysicist and as a cleric, in
which role he ministered to the needs of his congregation at the
