The wooden bridges built in Swizerland by Hans Ulrich Grubenmann (1709-83) and, in particular, by his older brother Johannes Grubenmann (1707-71) were notable for the 'hanging work' principle that they perfected. This technique of overlapping and bolting timbers allowed for much increased spans without relying on piers. On 29-31 May 1780 when Soane made these drawings, he was on his way home and thence to Downhill in Northern Ireland to take up a commission from Frederick Hervey, Bishop of Derry and Earl of Bristol (see Soane's early works, 1770-1785: a Grand Tour of 1770-2 and studied fifteen or so wooden bridges. He later had many of the record drawings, made by his accompanying draughtsman Michael Shanahan, engraved. These were not formally published but a set of 32 plates are in the RIBA Library, entitled 'Plans and Elevations Of Stone and Timber Bridges in France, Germany, Switzerland, and Italy; Together with a Plan of an intended Bridge at London-derry'. Besides his own interest in bridges, Soane's motive for making the drawings must relate to Hervey's (unrealised) project for a bridge over the River Foyle in the City of Londonderry.
All four drawings catalogued here were exhibited in 'John Soane and the wooden bridges of Switzerland. Architecture and the culture of technology from Palladio to the Grubenmanns', in Mendrisio, Vicenza, Basel and, London, 2002-3. A comprehensive exhibition catalogue published by Accademia di Architettura Mendrisio (in English) 2003, fully describes and discusses these drawings and gives the relevant history of Swiss wooden bridges (see pp.90-5 et passim).
Further literature. P.du Prey, John Soane's architectural education 1753-80, 1977, pp.325-32; P.du Prey, ‘Eighteenth-century English sources for a history of Swiss wooden bridges’, Zeitschrift fur schweizerische Archaologie und Kunstgeschichte, XXXVI, 1979, pp. 56-7; P.du Prey, John Soane: the making of an architect, 1982, pp.103-4; G.Darley, John Soane: an accidental Romantic, 1999, pp.54-5