_The exteriour black line marks each increase & the interiour dotted line shews the state of the little Mountain before that increase, so that the dotted line in the Drawing of Oct 18.^{th} shews the Size of the little Mountain July 8.^{th} the little spot A. marks where the lava came out some days before the great Eruption. B. C. D. mark the ancient Crater & E. the little Mountain the day before the Eruption. F. G. is the present Crater, & the exteriour black line H. F. G. the present shape of the top of Mount Vesuvius. Since May last the Mountain is increased from B. to F. which is near 200 feet._] PLATE III. Views of the gradual increase of the little mountain within the ancient crater; and of the present shape of Mount Vesuvius. LETTER III. To MATHEW MATY, M. D. Secretary to the Royal SOCIETY. Villa Angelica, near Mount Vesuvius, October 4, 1768. SIR, I have but very lately received your last obliging letter, of the 5th of July, with the volume of Philosophical Transactions. I must beg of you to express my satisfaction at the notice which the Royal Society hath been pleased to take of my accounts of the two last eruptions of Mount Vesuvius. Since I have been at my villa here, I have enquired of the inhabitants of the mountain, after what they had seen during the last eruption. In my letter to Lord Morton, I mentioned nothing but what came immediately under my own observation: but as all the peasants here agree in their account of the terrible thunder and lightning, which lasted almost the whole time of the eruption, upon the mountain only; I think it a circumstance worth attending to. Besides the lightning, which perfectly resembled the common forked lightning, there were many meteors, like what are vulgarly called _falling stars_. A peasant, in my neighbourhood, lost eight hogs, by the ashes falling into the trough with their food: they grew giddy, and died in a few hours. The last day of the eruption, the ashes, which fell abundantly upon the mountain, were as white almost as snow[14]; and the old people here assure me, that is a sure symptom of the eruption being at an end. These circumstances, being well attested, I thought worth relating.