The towers of the Spanish optical telegraph. Antecedents and variants of the architectural type

The Spanish optical telegraph was planned by the Ministry of the Interior in 1844 for civilian governmental use. It was a ‘tower and telescope’ telegraph developed by Colonel José María Mathé, with a design clearly inspired by military sensibilities and considerations. This paper first analyses the contemporary military reference point of the embrasure tower as a military stronghold campaign. It goes on to examine the historical antecedents of watchtowers or signal towers from the 16th century and the freestanding or outpost towers from the 17th century. This is followed by a description of the architectural type of telegraph tower and an analysis of its variants, which gradually differed from the model typology in both form and materiality. Finally, it examines the military telegraph towers of the second and third Carlist wars. Thus, the historical and typological study emphasizes the military inspiration of the optical telegraph towers that has often gone unremarked in order to optimize the heritage characterization of the remaining structures.