Blas Cabrera y Felipe
(Arrecife, Lanzarote, 1878 - México D. F., 1945)

Blas Cabrera y Felipe studiedat the Instituto de Canarias in La Laguna and received his baccalaureate in June 1894. In September, he moved to Madrid to attend the Universidad Central. Initially, he intended to study law, but soon directed his energies toward science, influenced by his almost daily contact with Santiago Ramón y Cajal at the Café Suizo’s tertulia. He enrolled in the Faculty of Sciences in 1894 and graduated in 1900.
He began his doctoral studies in 1901 and finished his dissertation entitled “Variación diurna del viento.” Between 1902 and 1905, he was assistant professor of the Faculty of Sciences in Madrid. He was an experimental physicist and published several research articles on different scientific topics, but his most significant work during those years was dedicated to the properties of electrolytes, a subject on which he conducted research sporadically until 1918. Most of his work from those years were published in the Anales de la Sociedad Española de Física y Química, the periodical of the Sociedad Española de Física y Química, founded in 1903, with Cabrera among its founding members. Between 1903 -1937, he contributed 68 articles to this publication.
        
On March 2, 1905, he obtained the chair of Electricity and Magnetism at the Universidad Central. The following year, he married María Sánchez Real, a native of La Laguna, and on January 17, 1907 his first son, Blas Cabrera Sánchez, was born. (He eventually studied medicine and became a distinguished physiologist; he worked in Juan Negrín’s Laboratory of Physiology and was his personal secretary during the Civil War). They later had two more children: Luís, who studied architecture, and Nicolás, who distinguished himself in the same discipline as his father, physics.

On April 7, 1909 he was elected member to the Real Academia de Ciencias Exactas, Físicas y Naturales, where he held the seat number 22, succeeding Francisco de Paula Rojas. A year later, on 17 April 1910, he read his acceptance speech, entitled “El éter y sus relaciones con la materia en reposo.” The same year, he began to work with the Junta para Ampliación de Estudios (JAE) and was appointed director
of the Laboratorio de Investigaciones Físicas, which officially started its work in 1910. He held this position when the laboratory became the Instituto Nacional de Física y Química.
        
Although he was the director of the laboratory, Cabrera had enough sense to realize that he needed to go abroad to further develop his studies.  Therefore, in 1912 he requested a grant to the JAE for five months "in order to visit laboratories and conduct research on magnetism in France, Switzerland and Germany, “ a request that was granted.

He spent most of the time in Zurich working in Pierre Weiss’ laboratory, the Federal Polytechnic School, accompanied by physicist and chemist, Enrique Moles. The remarkable thing about the experience was that the whole project almost collapsed because Cabrera presented himself in Weiss’ laboratory without having made any prior arrangement. He was a prestigious scientist, professor at the main Spanish university, and director of a laboratory, but he was abroad in a precarious situation. This was precisely the challenge that Cabrera had to face: how to establish a structure in the international sphere; he was successful. In fact, the time he spent in Zurich was crucial to his career. Zurich and then Strasbourg (where Weiss was appointed director of the Institute of Physics in 1919) were cities with which he maintained a special relationship.
        
Thereafter, he focused mainly on magnetism and made important contributions in this field. Two particularly outstanding contributions were his modification of the Curie-Weiss law for the rare-earths metals, and his equation for the atomic magnetic moment that included the effect of temperature. With his work, Cabrera won international recognition, as evidenced by his many publications in international periodicals (at least 35), his participation in conferences and his election as a member of the Commission Internationale Scientifique of the Institut International de Physique Solvay in 1928.  In 1929, he replaced Leonardo Torres Quevedo in the International Committee of Weights and Measures, the body responsible for overseeing the operation of the Bureau International des Poids et Mesures. On 12 November 1928, he was elected member of the Academy of Sciences in Paris, and took the seat vacated by Arrhenius.

In Spain he held many different positions. Elías Tormo was appointed rector of the University of Madrid, and, on his proposal on 28 September 1929, Cabrera was appointed vice chancellor in charge of educational affairs. Soon, however, political events had their effect on Cabrera. On 30 January 1930, General Berenguer replaced Primo de Rivera as head of government and appointed Elias Tormo as minister of Public Education. Tormo appointed Cabrera as his successor (March 3) at the University of Madrid.  Cabrera went through a difficult period as rector because there were students’ demonstrations against educational reforms proposed by the government, and he left the position in March 1931.

He was also member of the Junta Constructora de la Ciudad Universitaria (1931), president of the Real Academia de Ciencias (1934-1938), and of the Sociedad Española de Física y Química in 1916 and 1923. On January 26, 1936, he took the seat left vacant after Santiago Ramón y Cajal’s death in 1934, in the la Real Academia Española.

He also focused on the dissemination of physics among the general public through lectures and books such as ¿Qué es la electricidad? (1917), and Principio de relatividad (1923), both published by the Residencia de Estudiantes. In 1934, he was appointed rector of the International Summer University of Santander by the government of the Republic, succeeding Ramón Menéndez Pidal.  He was there when the Civil War began. As head of the university, Cabrera organized the return of teachers and students to Madrid, where he arrived in September. Soon, however, he left Spain, for there is evidence that on October 9 he and his wife were in Paris at the Colegio de España in the Cité Universitaire, which was his residence and that of other Spanish intellectuals exiled in Paris throughout his stay in the French capital.

In Paris, Cabrera worked at the Bureau International des Poids et Mesures as secretary of the overseeing committee. After the war, the government led by General Franco, who considered Cabrera as one of his enemies (he was expelled from his chair by an order published in the Boletín Oficial del Estado, 14 February 1939), put pressure to have him expelled from his position in Paris. He did not want to create problems for the Bureau, resigned and left France bound for Cuba in October 1941. Finally, and already weakened by a nervous system disorder that he suffered -Parkinson's disease-, he settled in Mexico D. F., where the Universidad Autónoma de México welcomed him as professor of Atomic Physics and History of Physics. He continued to publish articles (some of them in Ciencia, a periodical founded by the Spanish exiles, which he headed after the death of Ignacio Bolívar), and a monograph summarizing his work, El magnetismo de la materia.