48, that one persecutes me forever? One single barricade did I construct - it held, because it was practical, and as it was practical, it was beautiful", wrote Semper in dismay. Post-revolutionary period (1849–1855) After stays in Zwickau, Hof, Karlsruhe and Strasbourg, Semper eventually ended up back in Paris, like many other disillusioned Republicans from the 1848 Revolutions (such as Heinrich Heine and Ludwig Börne). In the fall of 1850, he travelled to London, England. But while he was able to pick up occasional contracts — including participation in the design of the funeral carriage for the Duke of Wellington and the designs of the Canadian, Danish, Swedish, and Ottoman sections of the 1851 Great Exhibition in the Crystal Palace — he found no steady employment. If his stay in London was disappointing professionally, however, it proved a fertile period for Semper's theoretical, creative and academic development. He published Die vier Elemente der Baukunst (The Four Elements of Architecture) in 1851 and Wissenschaft, Industrie und Kunst (Science, Industry and Art) in 1852. These works would ultimately provide the groundwork for his most widely regarded publication, Der Stil in den technischen und tektonischen Künsten oder Praktische Ästhetik, which was published in two volumes in 1861 and 1863. Zürich period (1855–1871) Concurrently with the onset of the industrial revolution, the Swiss Federation planned to establish a polytechnical school. As the principal judge for the competition held to select a design for the new building, Semper deemed the submitted entries unsatisfactory and, ultimately, designed the building himself. Proudly situated (where fortified walls once stood), visible from all sides on a terrace overlooking the core of Zurich, the new school became a symbol of a new epoch. The building (1853–1864), which despite frequent remodeling continues to evoke Semper's concept, was initially required to accommodate not only the new school (known today as the ETH Zurich), but the existing University of Zurich, as well. In 1855, Semper became a professor of architecture at the new school and the success of many of his students who attained success and renown served to ensure his legacy. The Swiss architect Emil Schmid was one such student. With his income as a professor, Semper was able to reunite his family, bringing them to Zurich from Saxony. The City Hall in Winterthur is among other buildings designed by Semper in Switzerland. In 1861, Semper and his family were awarded Swiss