Smith, John Thomas. Remarks on rural scenery; with twenty etchings of cottages, from nature; and some observations and precepts relative to the pictoresque. By John Thomas Smith, Engraver of the Antiquities of London. London, [1797]. Eighteenth Century Collections Online. Gale. Harvard University Library. 24 Feb. 2011 . also of interest https://mackereleconomics.wordpress.com/2009/04/28/composition-rules-especially-when-its-good/