cooled. He melted limestone in a retort made from a gun barrel, to show that it did not decompose when melted under pressure. His results were published in the Transactions of the Royal Society of Edinburgh and were well received by those like John Playfair who wanted to use Hutton's theory to promote a more mathematical approach to geology. He also carried out the first analogue modelling to investigate the formation of folds, work published in 1815. Hall travelled extensively in Europe to examine geological formations of the Alps and Mount Etna, and noted the similarity of lava flows in Italy to locations in Scotland. Sir James Hall was President of the Royal Society of Edinburgh, and author of various works on architecture and the sciences. Family He married Helen Douglas (d. 1837), daughter of Dunbar Douglas, 4th Earl of Selkirk and sister of the 5th Earl of Selkirk. They had three daughters and three sons. Hall died at home at 132 George Street in the New Town in Edinburgh, Scotland. He is buried in Greyfriars Kirkyard in central Edinburgh. The grave lies against the western wall of the original churchyard, backing onto George Heriots School. He was succeeded by his son and heir, Sir John Hall, 5th Baronet, FRS. Another son, Basil Hall, was a noted traveller and writer; his daughter Eliza was mother of Houston Stewart Chamberlain. His daughter Magdalene Hall (1793-1822) married firstly 1815 Colonel Sir William Howe De Lancey and secondly Captain Henry Harvey; she was author of A Week at Waterloo (first privately published) and died in childbirth with her third child. By De Lancey, her first husband, Magdalene had no issue. He was an agnostic or atheist. Publications Essay on the Origins and Principles of Gothic Architecture (1797) See also Scottish Enlightenment References Bibliography M. D. Eddy, 'Geology, Mineralogy and Time in John Walker's University of Edinburgh Natural History Lectures', History of Science, 39 (2001), 95-119. M. D. Eddy, 'The University of Edinburgh Natural History Class Lists', Archives of Natural History, 30 (2003), 97-117. M. D. Eddy, The Language of Mineralogy: John Walker, Chemistry and the Edinburgh Medical School, Aldershot : Ashgate Publishing Ltd, 2008, [Hall is discussed throughout the book, especially in the introduction and conclusion]. The Royal Families of England, Scotland, and Wales, with their Descendants, etc., by Messrs, John and John Bernard Burke, London, 1848: vol.1, pedigree CXXVI. Ten Parishes of