[ Oporto Earthquake, 1793. ] Manuscript transcription of first-person account (by William Sibbald?) headed 'An Essay on Earthquakes, occasioned by a most dreadful convlusion of Nature that was horribly felt here [Oporto, Portugal] this morning.'

27pp., 4to. Unbound. On thirteen bifoliums, and one loose leaf, formerly attached with string. Corner of first page embossed with small circle containing Prince of Wales feathers and words 'SUPERFINE SATIN'. In good condition, on lightly aged paper. Headed: 'Oporto 2d May 1793. | An Essay on Earthquakes occasioned by a most dreadful convulsion of Nature that was horribly felt here this morning. This is written from immediate feeling by a Father for his Children'. (A son Charles is named.) The document derives from the Sibbald family archive, and may have been transcribed by William Sibbald himself. After a pious exhortation, it begins: 'A little after midnight, your Mother being busy with her needle, and I having finished an Essay for my dear children, for their future instruction, was in the act of reading it to her my dear Infants fast asleep in the adjoining room, and all except my voice, was silent as the grave. A hurling noise, not very loud but strong and unlike anything I ever heard before, attended with rattling of all the Windows, and some shaking of the House, but not very severe, suddenly stopt me - your Mother looked somewhat alarmed, but her idea was Thunder, that was not mine, [...]'. Over the next couple of pages the author gives a brief account of how he calmed his wife. He states that he has 'several times seen eminent danger, and death as if it were staring me in the face, without agitation', and has 'more than once extricated myself from perils, by determinations seemingly rash but necessary'. A disquisition on 'the nature and causes of earthquakes' follows over a number of pages, with the rest of the document taken up by a lengthy anecdote (fictional?) concerning 'a Scotch gentleman who possessed much humour and learning' at Madrid sixty years previously. The Scotsman is a highlander, and humours the belief of a couple of individuals that he has second sight and can raise the devil. The document ends: 'Mr Gordon hugged himself on his success - Let us enquire what it was - that he had driven two Men out of their senses, who continued insane all their lives - Mr Gordon who was a good natured Man at bottom, would often groan in spirit saying he repented sincerely of having carried his fun quite so far'. The last five lines read: 'Note - The Earl Marshall was a most accomplished clever Man, was in the Rebellion of 1715 fled to Spain became a Grandee, a General Officer and in high reputation as an agreeable polite Man'.