The Illustrated London News, 17 March 1849, pp. 176–177. A major source for his life is a series of reminiscences by his son Leopold, published in sixteen parts in the Newcastle Weekly Chronicle in 1889. There are a number of surviving letters and reminiscences by, among others, B.R. Haydon, John Constable, Ralph Waldo Emerson, the Rossettis, Benjamin Disraeli, Charlotte Brontë and John Ruskin – a persistent critic who, even so, admitted Martin's uniqueness of vision. The first full biography was that by Mary L. Pendered whose chief source, Martin's friend Sergeant Ralph Thomas, wrote a diary – now lost – of their friendship. Thomas Balston then wrote two biographies on the artist, the first in 1934, and the second (still the leading biography) in 1947. Christopher Johnstone produced an introductory book on Martin 1974, and in 1975 the art critic William Feaver was author of an extensively illustrated work on Martin's life and works. Since 1986, Michael J. Campbell has produced a number of publications on John Martin, including the leading publication on his work as an original printmaker, published by the Royal Academy of Arts, Madrid, in 2006. In 2011–12 Tate Britain and Newcastle's Laing Art Gallery co-curated a major retrospective exhibition of Martin's work in all genres -"John Martin – Apocalypse" – including his contribution as a civil engineer. Featured in the exhibition was the fully restored The Destruction of Pompeii and Herculaneum, 1822. Recorded as lost in the disastrous Tate Gallery flood of 1928, the painting was rediscovered by Christopher Johnstone, a research assistant at the gallery, when he was researching his book John Martin (1974). Its restoration by Tate conservator Sarah Maisey, reveals that the original paintwork was in near pristine condition; a large area of missing canvas has been repainted by Maisey using techniques that were not available in 1973 as she describes on page 113 of the exhibition catalogue John Martin: Apocalypse (2011). When rediscovered the painting was rolled up inside the missing Paul Delaroche painting The Execution of Lady Jane Grey which was returned to the National Gallery, London. Family Wife and children With his wife Susan, née Garrett, who was nine years older than him, Martin had six children who survived to adulthood: Alfred (who worked with his father as a mezzotint engraver and later became a senior tax official), Isabella, Zenobia (who married the artist Peter Cunningham), Leopold (who became a