During this extended tour, from 25 September 1840 to 30 June 1841, when he was convalescing from tuberculosis, Ruskin wrote to his 'College Friend', the Revd Edward Clayton, from Naples on 12 February 1841 announcing his first plans for 'a work of some labour' which would take him 'several years to complete', but for which he was not then strong enough to read ( Works, 1.434). As there are no extant manuscripts of Modern Painters I from this period and few references to the project in Evans and Whitehouse, The Diaries of John Ruskin, we can only guess what progress was made during the tour. Ruskin was clearly thinking about Turner 's paintings as he witnessed particular effects of light on landscapes and buildings ( Evans and Whitehouse, Diaries I, pp.103, 136, 186), but any attempt at writing was dependent upon Ruskin's health. As late as 9 June 1841 he wrote to his former tutor, the Revd Professor Thomas Dale, from Lausanne reporting that, after the most recent recurrence of his symptoms, 'hard mental labour of any kind' hurt him 'instantly' ( Works, 1.389). (See a restful summer (1841), long gestation period of Modern Painters I.)