Leonardo Torres Quevedo (; 28 December 1852 – 18 December 1936) was a Spanish civil engineer, mathematician, and inventor who developed numerous engineering innovations related to aerial trams, airships, catamarans, and remote control. He was also a pioneer in the fields of computing and robotics, while maintaining an active role in several scientific and cultural institutions. He held prominent positions, such as Seat N of the Real Academia Española (1920–1936) and the presidency of the Spanish Royal Academy of Sciences (1928–1934). In 1927, he became a foreign associate of the French Academy of Sciences.
His first innovative design was a cableway system patented in 1887 for the safe transport of passengers, an endeavor that led to the Mount Ulia aerial ropeway in 1907 and culminated in 1916 with the opening of the Whirlpool Aero Car at Niagara Falls. In the 1890s, Torres focused his efforts on analog computation. He published Sur les machines algébriques (1895) and Machines à calculer (1901), technical studies that earned him recognition in France for his construction of machines capable of solving real and complex roots of polynomials.González de Posada, Francisco. González Redondo, Francisco A. Leonardo Torres Quevedo (1852–1936). 1ª Parte. Las máquinas algébricas., La Gaceta de la RSME, 2004.Girvan, Ray. The revealed grace of the mechanism: computing after Babbage, May 2003. At the beginning of the 20th century, he made significant aeronautical contributions by developing the non-rigid Astra-Torres airships, whose trilobed structure helped the British and French armies counter Germany's submarine warfare during World War I.González Redondo, Francisco A. The Aeronautical Contribution of Leonardo Torres Quevedo: from World War I to 21st Century. Cockade International Journal (1360–9009) January 2009, 40(3):151–161. This work in aeronautics would lead him to become a key figure in the development of radio control systems between 1901 and 1905 with the Telekino, which introduced modern wireless remote control operation principles.
From his Laboratory of Automatics established in Madrid in 1907, Torres built El Ajedrecista (The Chess Player) in 1912, an electromagnetic device capable of playing a chess endgame which demonstrated that machines could follow specific rules and heuristics, contributing to early developments in physical automata and artificial intelligence. Expanding upon the work of Charles Babbage in his 1914 paper Essays on Automatics, he explored theories of thinking machines and designed a special-purpose electromechanical calculator that conceptually foreshadowed floating-point arithmetic. British historian Brian Randell described it as "a fascinating work which well repays reading even today." Torres later demonstrated the feasibility of an electromechanical analytical engine by successfully producing a typewriter-controlled calculating machine in 1920.
Before his retirement in 1930, Torres conceived other advanced designs, particularly in the field of naval architecture. Among the most notable were the Buque campamento (Camp-Vessel, 1913), a balloon carrier designed to transport airships attached to a mooring mast of his invention,González Redondo, Francisco A. «Del 'buque-campamento' de Torres Quevedo (1913) al 'Dédalo' (1922) de la Armada Española», Revista General de Marina, noviembre de 2017, pp. 645–656. and the Binave (Twin Ship, 1916), a multihull steel vessel featuring flexible structural joints and independent propulsion systems that solved the stability and torsion issues of earlier catamarans.Pérez Fernández, Rodrigo. González Redondo, Francisco A. On the origin, foundational designs and first manufacture of the modern catamaran, International Journal of Maritime History, Sage Publishing, Volume 34, Issue 3, 1 February 2022. In addition to his interests in engineering, Torres also stood out in the field of letters and was a prominent speaker and supporter of Esperanto.
Early life and education
Torres was born on December 28, 1852, the Day of the Holy Innocents, in Santa Cruz de Iguña, Cantabria, Spain. His father, Luis Torres Vildósola y Urquijo (1818–1891), was a civil engineer in Bilbao, where he worked as a railway engineer. His mother was Valentina Quevedo de la Maza (1825–1891). He had two siblings, Joaquina (b. 1851) and Luis (b. 1855–1923). The family resided mainly in Bilbao, although they also spent long periods at his mother's family home in the Cantabrian mountains. During his childhood, he spent long periods of time away from his parents due to their work trips. Therefore, he was cared for by his father's relatives, the Barrenechea sisters, who declared him heir to their properties, which facilitated his future independence.
He completed his secondary education in Bilbao and moved to Paris in 1868, attending the Christian Brothers' school for two years to further his studies. There, he familiarized himself with French culture, customs, and language, an experience that ultimately benefited his scientific and technical relations with foreign figures and institutions. In 1870, his father was transferred, taking his family to Madrid. The following year, Torres began his higher education at the . He temporarily interrupted his studies in 1873 to enlist as a volunteer, along with his brother Luis, in the defense of Bilbao, which had been besieged by Carlist troops during the Third Carlist War. Once the siege of Bilbao was lifted in 1874, he returned to Madrid and completed his studies in 1876, graduating fourth in his class.
Career
After graduating, Torres worked as a civil engineer for a few months on railway projects, as his father had done, but his curiosity and desire to learn led him to resign from the civil engineering corps. As a young entrepreneur who had inherited a considerable family fortune, he immediately set out on a long trip through Europe, visiting Italy, France and Switzerland, to learn about the scientific and technical advances of the day. He later explained his decision: "taking a position in the Civil Service, I was convinced of my lack of love for the methodical and disciplined work of offices, and I resigned from it to dedicate myself to thinking about my own things." Upon returning to Spain in 1877, he settled in Santander to continue his self-funded research.
Cableways
Torres' studies in the field of cableways began around 1880, during his residence in his hometown of Molledo. There, in 1885, he constructed the first cableway, which spanned a depression of some . The cableway was about wide and carried a single person seated in a chair suspended from a cable, with another traction cable. The engine used to move the human cargo was a pair of cows. In 1887, he would build a much larger, motorized cableway over the Río León in , but it was intended solely for transporting materials.
These experiments formed the basis of his first patent application on 17 September, 1887, in Spain, "" ("A multi-wire suspended aerial system"),Un sistema de camino funicular aéreo de alambres múltiples, Patentes de invención de Don Leonardo Torres Quevedo, pp. 5–12, España Registro de la Propiedad Industrial, 1988. ISBN 84-86857-50-3 for a passenger cableway system with which he achieved a level of safety suitable for transporting people, not just materials. The patent was extended to other countries: the United States, Austria, Germany, France, the United Kingdom, and Italy.Reproducciones de títulos extranjeros correspondientes a la patente española n.º 7348, Patentes de invención de Don Leonardo Torres Quevedo, pp. 13–15, España Registro de la Propiedad Industrial, 1988. ISBN 84-86857-50-3 His system introduced a multiple-cable support arrangement in which one end of a cable is anchored to fixed counterweights and the other (via a pulley system) to movable counterweights. With this system, the axial force of the cables is constant and equal to the weight of the counterweight, regardless of the load on the car. What varies with this load is the deflection of the cables, which increases as the counterweight is raised. Therefore, the safety factor of these cables is perfectly known and independent of the car's load. The resulting design is very robust and remains safe in case of a support cable failure.Rafael López-García. Marco Ceccarelli. Distinguished Figures in Mechanical Engineering in Spain and Ibero-America., Springer Nature, p. 322, 2023. ISBN 978-3031310751
In April 1889 Torres presented his cableway system in Switzerland, a place very interested in this means of transport due to its geography, between Pilatus-Kulm and Pilatus-Klimsenhorn (Mount Pilatus). It was an aerial funicular with a length of 2 km and a gradient of 300 m. In 1890 he traveled to that country to convince different authorities of its construction. He failed to convince the Swiss authorities, who did not grant any reliability to the work of a Spanish engineer due to contemporary skepticism surrounding early aerial transport systems. This disappointment, known as the "Swiss failure", led him to focus on other fields for several years. On 30 September 1907, Torres put into operation the first cableway of his system intended for safe public transport, the in San Sebastián.Klaus Hoffmann. Recent Developments in Cable-Drawn Urban Transport Systems,(pdf) p. 206, vol. 34, No. 4, 2006, FME Transactions. The journey was 280 meters, with a drop of 28 meters, lasted for just over three minutes, and the gondola had the capacity to board up to 18 people on each trip. The execution of the project was the responsibility of the Bilbao Society of Engineering Studies and Works, founded in 1906 by Valentín Gorbeña to develop and commercialize Torres' patents. The Ulia cableway remained in operation until 1917 and the practical viability of its design paved the way for similar passenger transport systems in other countries.Rafael López-García. Marco Ceccarelli. Distinguished Figures in Mechanical Engineering in Spain and Ibero-America., Springer Nature, pp. 323-324, 2023. ISBN 978-3031310751
The successful outcome of this type of aerial tramway gave him the opportunity to design the Spanish Aerocar based on J. Enoch Thompson's idea at Niagara Falls in Canada. The 550-meter-long system is a cableway that crosses the whirlpool in the Niagara Gorge on the Canadian side. It travels at about . The load per cableway is , with a safety factor for the cables of 4.6, and carries 35 standing passengers on a one-kilometer journey. It was built between 1914 and 1916. For its construction and assembly, the Niagara Spanish Aerocar Company Limited was created from the Society of Engineering Studies and Works, with a capital of $110,000 (roughly $ million in ), and a planned 20-year concession. Construction was directed by Torres's son, Gonzalo Torres Polanco.Rafael López-García. Marco Ceccarelli. Distinguished Figures in Mechanical Engineering in Spain and Ibero-America., Springer Nature, p. 324, 2023. ISBN 978-3031310751 It completed its first tests on February 15, 1916, and was officially inaugurated on August 8, opening to the public the following day. The system remains in operation with only minor modifications and has become a notable tourist and engineering landmark.