Mataró prison (1863), the first prison building planned on the "panoptical" principle (that is, with every part of the building visible from a central point), devised by the English philosopher Jeremy Bentham in the 18th century. The Vallvidrera dam (1865) Casa Arnús (1868), in Passeig de Gràcia (Barcelona)—not to be confused with another building of the same name by Enric Sagnier. Casa Almirall (1870) in Carrer Pelai (Barcelona) The old building of the University of Barcelona (1873), with strong mediaeval influence.