Note 4 — LETTER I.

I am convinced, that it might be very practicable to divert the course of a lava when in this state, by preparing a new bed for it, as is practised with rivers. I was mentioning this idea at Catania in Sicily, when I was assured, that it had been done with success during the great eruption of Etna, in 1669; that the lava was directing its course towards the walls of Catania, and advancing slowly like the abovementioned, when they prepared a channel for it round the walls of the town, and turned it into the sea; that a succession of men, covered with sheep-skins wetted, were employed to cut through the tough flanks of the lava, till they made a passage for that in the centre (which was in perfect fusion) to disgorge itself into the channel prepared for it. A book I have since met with gives the same account of this curious operation; it is intituled, Relatione del nuovo incendio fatto da Mongibello 1669. Messina, Giuseppe Bisagni, 1670. His Sicilian Majesty's palace at Portici, and the valuable collection of antiquities that have been recovered from beneath the destructive lava's of Vesuvius, are in imminent danger of being overwhelmed again by the next that shall take its course that way; whereas, by taking a level, cutting away and raising ground, as occasion might require, the palace and museum would, in all probability, be insured, at least against one eruption; and, indeed, I once took the liberty of communicating this idea to the King of Naples, who seemed to approve of it.