An Account of Several Earthquakes Felt in Wales. By Thomas Pennant, Esq. F. R. S. in a Letter to Sir Joseph Banks, P. R. S.

XII. An Account of several Earthquakes felt in Wales. By Thomas Pennant, Esq. F. R. S. in a Letter to Sir Joseph Banks, P. R. S. Read January 25, 1781. Dear Sir, It is very singular, that in three days after my return home I should be reminded of my promise by a repetition of the very phenomenon on which I had engaged to write to you: for on Saturday last, between four and five in the evening, we were alarmed with two shocks of an earthquake; a slight one, immediately followed by another very violent. It seemed to come from the north-east, and was preceded by the usual noise; at present I cannot trace it farther than Holywell. The earthquake preceding this was on the 29th of August last, about a quarter before nine in the morning. I was forewarned of it by a rumbling noise not unlike the coming of a great waggon into my court-yard. Two shocks immediately followed, which were strong enough to terrify us. They came from the north-west; were felt in Anglesea, at Caernarvon, Llanrwst, in the isle of Clwyd south of Denbigh, at this house, and in Holywell; but I could not discover that their force extended any farther. The next in this retrograde way of enumerating these phenomena was on the 8th of September 1775, about a quarter before before ten at night, the noise was such as preceded the former; and the shock so violent as to shake the bottles and glasses on the table round which myself and some company were sitting. This seemed to come from the east. I see in the Gentleman's Magazine of that year, that this shock extended to Shropshire, and quite to Bath, and to Swansea in South Wales. The earliest earthquake I remember here was on the 10th of April 1750. It has the honour of being recorded in the Philosophical Transactions, therefore I shall not trouble you with the repetition of what I have said. Permit me to observe, that I live near a mineral country, in a situation between lead mines and coal mines; in a sort of neutral tract, about a mile distant from the first, and half a mile from the last. On the strictest inquiry I cannot discover that the miners or colliers were ever sensible of the shocks under ground: nor have they ever perceived, when the shocks in question have happened, any falls of the loose and shattery strata, in which the last especially work; yet, at the same time, the earthquakes have had violence sufficient to terrify the inhabitants of the surface. Neither were these local; for, excepting the first, all may be traced to very remote parts. The weather was remarkably still at the time of every earthquake I have felt. I remain, with true regard, &c.