IN ONE of his rare moments of lucidity, Hamlet tells his friend Horatio exactly how he hopes to trap the king, and explains in an uncharacteristically forthright way what the failure of his subterfuge will mean:
If his occulted guilt
Do not itself unkennel in one speech,
It is a damned ghost that we have seen,
And my imaginations are as foul
As Vulcan's stithy.
Now, Vulcan, to whom the Prince refers, was God of Fire in heaven, and by appointment, official blacksmith to the gods. He was the son of Jupiter and Juno, and on one occasion when this normally harmonious pair were having something of a tiff, Vulcan unwisely took his mother's side. The angry Jupiter promptly threw him out of heaven:
From morn
To noon he fell from noon to dewy eve,
A summer's day; and with the setting sun
Dropped from the zenith like a falling star
On Lemnos, the Aegean isle.
Vulcan recommended his business here on earth, establishing his many workshops under Mount Etna, Vesuvius and as we have seen in recent days, in Iceland, where evidence of his activity is there, for all to see. Naturally such mountains came to be named after him: they are called volcanoes.
Nowadays, of course, we have other explanations for such happenings. We know that the centre of the earth is very hot, and that even relatively close to the surface there can be found vast reservoirs of molten rock, called magma. If the pressure in a magma chamber becomes greater than its roof can stand, the molten rock bursts forth at the weakest point, often at the joints between the vast tectonic plates that make up the surface of the earth.
If the molten rock is thin and runny, like basalt, it allows the gases formed within to bubble freely, and to escape easily upwards without explosive consequence. Such a volcano is described as Hawaian or Strombolian, since these examples are typical of this relatively mild activity.
But if the melted rock is thick and toffee like, as is the case with molten granite, the bubbles of the gas within have difficulty making their escape; very high pressure build up, and culminate in a violent explosion. This is a plinian eruption, so called because it was described so vividly by the Roman writer Pliny who witnessed the eruption of Vesuvius in AD 79.