“On the 24th of August,” writes Pliny the Younger some eleven years after the event he is about to describe, “about one in the afternoon, my mother desired my uncle to observe a cloud which appeared of a very unusual size and shape. He had just returned from taking the benefit of the sun, and after bathing himself in cold water, and taking a slight repast, was retired to his study. He immediately arose and went out upon an eminence, from whence he might more distinctly view this very uncommon appearance. It was not at that distance discernible from what mountain this cloud issued, but it was found afterwards to ascend from Mount Vesuvius. I cannot give a more exact description of its figure than by resembling it to that of a pine-tree, for it shot up to a great height in the form of a trunk, which extended itself on the top into a sort of branches, occasioned, I imagine, either by a sudden gust of air that impelled it, the force of which decreased as it advanced upwards, or the cloud itself being pressed back again by its own weight, expanded in this manner; it appeared sometimes bright, and sometimes dark and spotted, as it was more or less impregnated with earth and cinders. This extraordinary phenomenon excited my uncle’s philosophical curiosity to take a nearer view of it.” The nephew then proceeds to relate how his uncle sailed by way of Retina, the port of Herculaneum, to Stabiae, where he met with his second in command, one Pomponianus. Meanwhile the Younger Pliny, who had declined to accompany his uncle’s expedition on the plea of having to pursue the studies with which as a hard-working youth of seventeen he was evidently engrossed, became alarmed during the night for the Elder Pliny’s safety. His own and his mother’s terrible experiences are vividly portrayed in the second letter, which, at the historian’s special request, the Younger Pliny wrote to Tacitus in later years.