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including coal, limestone, gneiss and granite in which no evidence of
the effect of heat could be seen. Basalt contains zeolites, rich in water,
and calcite, which contains 'fixed air', and so could not have been
heated. He also objected to the findings of Sir James Hall who had
taken basalt and melted it, then allowed it to recrystallise, in order to
show the similarity of the recrystallised with the original, thus prov-
ing that basalt was magmatic (igneous) in origin. The recrystallised
basalt, like the original, contained minute air bubbles. Kirwan had
previously argued that such bubbles were characteristic of basalt
deposited in water, an argument that failed to find favour with the
Scottish petrologists. As Peter Wyllie of the California Institute of
Technology has written, these experiments earned Hall the later
title of 'Father of Experimental Petrology'.
IDEAS ON THE ORIGINOF THE GIANT'S CAUSEWAY
The Giant's Causeway (Figure
6.3
) in northeast Ireland is one of the
geological wonders of the world. In 1740 the Dublin Society's promo-
tion of art was responsible for bringing it to the attention of many
people in Europe. That year the Society offered a £25 premium for art
and one of the entries was from a Susanna Drury, a Dublin artist. She
submitted several excellent canvasses of views of the Giant's
Causeway in County Antrim, which she painted over a period of
three months. Miss Drury was awarded the premium and subse-
quently her images were engraved in London by Fran¸ois Vivar` s. It
was these prints that were distributed across Europe and that initiated
a steady stream of visitors to the Causeway coast. The Lord Bishop,
Augustus Hervey (1730-1803), Bishop of Derry and fourth Earl of
Bristol, apparently installed steps down to the site. Visitors included
John Wesley in 1778, John Whitehurst in 1783, Abraham Mills in
1787-88, Humphry Davy in 1806 and Jean-Fran¸ois Berger in 1811. It
is not outrageous to suggest that Susanna Drury is the most important
person in the history of Irish geology.
Nicholas Desmarest never viewed the Giant's Causeway, but on
seeing Vivar` s' engravings he declared that the basalts that formed the
