ABSTRACT
At ten o'clock in the morning of 24 August AD 79 smoke began to issue from Mount Vesuvius. It was the beginning of an eruption which was to engulf the towns immediately to its south and west, and in so doing encapsulate them in a layer of volcanic matter which was to preserve them to our own day. The prevailing southerly winds carried a hail of red hot volcanic ash over the towns of Pompeii and Stabiae and buried them to a depth of four to five metres. The torrential downpour which accompanied the last stages of the eruption washed a slimy ooze of ash and mud down the slopes of the mountain to cover the small town of Herculaneum to a depth of 15-20 metres. Oplontis, which lay midway between Pompeii and Herculaneum, and which is only now beginning to be uncovered, disappeared under a combination of ash and mud. Pliny the younger, whose uncle died in the disaster, wrote an eye witness account of it (Letters, 6. 16):
My uncle was at Misenum and was personally commanding the fleet. On 24 August in the early afternoon my mother pointed out to him a cloud of unusual size and appearance It was not clear as we were so far away which mountain the cloud was rising from (it was afterwards known to be Vesuvius). Its appearance can only be expressed as being like an umbrella pine, for it rose to a great height on a sort of trunk and then split off into branches, I imagine because it was thrust upwards by the blast which had just occurred and then left unsupported as the pressure subsided, or else was borne down by its own weight so that it spread out and dispersed. In places it looked white, elsewhere spotty and dirty, according to the amount of soil and ashes it contained.
