He was educated very well from early on, receiving a scholarship from the municipality (rare for the time), allowing him to study at the Chalon Middle School. His teachers suggested that he look for a position as a teacher but Baillaud had higher ambitions. He was able to get his scholarship renewed upon his graduation, leading him to the lycée in Lyon where he studied special mathematics. There he lived with his uncle Louis Baillaud who had moved to Lyon to help his nephew.
Graduating from the lycée in Lyon, Baillaud entered the École Normale Supérieure. It was here that he spent the three years 1866 to 1869, and it was where he met and befriended future mathematician Jules Tannery and future physicist Edmond Bouty. These three would remain lifelong friends, and in some sense become each other's family: Baillaud would go on to marry, on 31 December 1873, Marie Hélène Pons (1847-1920), a sister of Bouty's wife; Tannery would go on to marry Baillaud's sister, Esther. Moreover, their children would maintain this family friendship. Baillaud graduated with a mathematics degree from the École Normale Supérieure in 1869 and was appointed to teach mathematics at the lycée in Montauban.
Baillaud, as a teacher, was not called for military service in the Franco-Prussian war of 1870-71. He did, however, serve in the National Guard in Montauban. In these early years he was involved in politics and made known his strong Republican views. He was one of the founders of the newspaper, Le Républicain de Tarn et Garonne. Over the following years he taught in the Lycée Saint-Quentin, the Lycée St Louis, the Lycée Louis le Grand, the Lycée Charlemagne, and the Lycée Condorcet.
He was appointed to roles in the Paris Observatory in the early 1870s. In 1872, he was made Élève Astronome (student astronomer) under Urbain Le Verrier, and in 1874, Aide Astronome (assistant astronomer). At this stage he was studying for his doctorate and consulted Charles Delaunay (the Director of the Paris Observatory), Charles Hermite and Victor Puiseux about possible topics for his research. He settled on studying perturbations of the motions of comets. Letters he wrote show his personality; for example writing to Edmond Bouty on 22 June 1872 (see ):-
I cannot ... conceal that I've always had at the bottom of my heart a little vanity and much ambition. ... I do not lack patience and even energy. ... I will be working ... as hard as a man can, and if I am needed, you will find me ready to put my knowledge to the service of science and my country.In 1876 he was awarded a doctorate in Mathematical Sciences for his thesis on perturbations of the motions of comets Exposition de la méthode de M Gylden pour le développement des perturbations des comètes Ⓣ. By 1877, he was lecturing on dynamical astronomy at the Sorbonne (University of Paris), substituting for Le Verrier who was ill. Le Verrier died in September 1877 and Félix Tisserand, who had been Director of the Toulouse Observatory since 1873, moved to the Paris Observatory to fill the vacancy in 1878. Baillaud, who had succeeded Le Verrier as Professor of Astronomy at the University of Paris, was a candidate for the vacant post in Toulouse.
In 1878, Baillaud was selected to be the Director of the Toulouse Observatory. He served in this role until 1907 when he returned to Paris. During much of his time working in Toulouse, he also operated as the Dean of the Faculty of Science of the University of Toulouse. He had been proposed for this role by the President of the University who wrote (see ):-
This is a man of great sense and of the strongest character ... he is a very intelligent man and very hardworking, very dedicated to the University with liberal ideas, who by his character will act as a leader of the professors, by his devotion he will have the best influence on students of the School.In the School of Sciences, he taught astronomy. He played a key role at the University, developing the Faculty :-
The buildings were old and inadequate; students were few in number, and the number of professors insufficient for these few. His first step was to secure from the Ministry of Education the means to call the eminent Émile Picard to the chair of mathematics and to build laboratories of physics and chemistry. Much needed additions were made to the scientific library. Finally, with the assistance of the city of Toulouse, additional land was acquired and buildings erected for the faculty of science which were adequate at the time.He raised the number of chairs from 9 to 20, and was responsible for the appointment of to-be-famous scientists such as Marie Henri Andoyer, Marcel Brillouin, Eugène Cosserat, Édouard Goursat, Gabriel Koenigs, Thomas Stieltjes and Ernest Vessiot in addition to Émile Picard. At the Observatory he aimed to expand its capabilities, attracting many collaborators and giving full support to the international Carte du Ciel Ⓣ project.
He also managed to improve the status of astronomy by re-launching the journal Annales de l'Observatoire de Toulouse in 1880, producing an initial volume of a new series, published in Paris. The series continued through to 1968. Moreover, upon his proposal, the journal Annales de Faculté des Sciences de Toulouse was created in 1886. He also disseminated his astronomical knowledge through public lectures, offering a popular course illustrated with photographs and drawings, for which the public were invited to the Observatory.
One of Baillaud's most impressive contributions to astronomy came after 1903, when the Toulouse Observatory took over the facility on the Pic du Midi, a mountain in the French Pyrenees. Founded by amateurs in the 1850s, the mountain-top observatory had been intended to house a telescope, but the 9400ft/2865m height above sea level proved too big of a logistical challenge, leaving the goal unrealised. Construction of the observatory had begun in 1878, but the spiralling costs had caused the work to be suspended in 1882. Upon the Toulouse take-over, Baillaud organised a team of soldiers to erect a 20in/0.5m reflecting telescope, and a 10in/0.25m refracting telescope on the summit. The 8m dome was completed in 1908. It was here that, in 1909, those working at the Observatory discredited the Martian canal theory, the belief during the late 19th and early 20th centuries that there were canals on Mars. It turned out that these 'canals' were merely optical illusions and were revealed to be so by the improved astronomical observations of the 20th century. It is thanks to Baillaud that this facility was in operation.
In 1902, he was made a Correspondent of the Académie des Sciences, leading to full membership in 1908. This year also saw him become an associate member of the Royal Astronomical Society and a member of the Bureau des Longitudes. He later became a corresponding member of the Imperial Academy of Sciences of Saint Petersburg (1913) and an associate member of the Accademia dei Lincei (1918).
He left Toulouse for Paris in 1908, when he became the Director of the Paris Observatory. His appointment had come at the end of a difficult process which had many twists and turns. The Minister made the appointment after receiving advice from the Academy of Sciences and the Council of the Paris Observatory. There were several candidates but the close call came between Baillaud and Guillaume Bigourdan. First one man and then the other appeared to be first choice. On 17 December 1907 some newspapers reported, prematurely, that Bigourdan had almost certainly won but when the official announcement came on 6 January 1908 it was Baillaud who was declared the new Director of the Paris Observatory.
On 26 March 1908 his colleagues at Toulouse gathered to wish him well in his position in Paris. One of his colleagues made a farewell speech (see ):-
As administrator we have seen that you have always had in mind the general interest, and that alone. We know that by your innate sense of right you have kept yourself free from prejudice and have rendered to each one the justice due him. But it would show little knowledge of your character to see in you only the administrator and the man of science. However eminent may be your professional attainments, much more exquisite are your personal qualities, the qualities of heart which, by a happy reciprocity, you have always esteemed so highly in others. ... No words could be more eloquent than the presence of ninety persons, administrators, colleagues, students, friends, who have come spontaneously to show that it is the man rather than the official that they love.He set out to re-launch the stalled Carte du Ciel Ⓣ project. It had been initialised in 1887 by Paris Observatory director Amédée Mouchez, who realised the potential of the new dry plate photographic process to revolutionise the process of making maps of stars. A congress, held in the Paris Observatory on 16 April 1887, had resolved: (i) to create a chart of all stars down to the fourteenth magnitude, the plates to be in duplicate (ii) to create a second series of photographs with shorter exposure, including stars to the eleventh magnitude, to be made concurrently to form a catalogue and to determine fundamental positions in the first series. It was realised, however, that the charts proved to be excessively expensive to photograph and reproduce, thus less attention was given to the project over time. Baillaud hosted a conference at the Observatory with entertainment in the form of singers from the Paris Opera, and refreshments of wine provided by the Bordeaux Observatory. Though the French government had agreed to fund the venture, it became increasingly clear that the objectives were too unrealistic. The project was never completed.
For two years from 1909, Baillaud served as the President of the French Astronomical Society (Société astronomique de France).
Baillaud held a keen interest in time standardisation, promoting Universal Time, the time standard based on the Earth's rotation. He was chosen in 1913 to be the director of the Bureau International de l'Heure, based at the Paris Observatory. It was the responsibility of the Bureau to combine different measurements of Universal Time. The Bureau also played an important role in the research into time keeping. Baillaud initialised the transmission of a time signal from the Eiffel Tower, and maintained the Observatory and time signal throughout the First World War, despite the fact that the German howitzer, Big Bertha, had its nominal coordinates for Paris set to the location of the Observatory.
Following the armistice after World War I, scientists began to reorganise. Baillaud was one of the most involved of those responsible for the creation of the International Astronomical Union, combining the Carte du Ciel Ⓣ, the Solar Union and the Bureau International de l'Heure, and he was elected as the founding president, serving from 1919 to 1922.
Baillaud retired as Director of the Paris Observatory in 1926, and was awarded with the title of Honorary Director.
He had eight children including two sets of twins: Émile 1874-1945, Jules 1876-1960, Madeleine 1877-1961, Henri 1877-1939, Marthe 1882-1978, René 1885-1977, Pierre 1885-1906, and Hélène 1892-1976. Two of his children became astronomers: Jules became an Assistant at the Paris Observatory; René became the Director of the Observatory of Besançon (1930-1957). A letter he wrote to his wife on 12 October 1891 reveals much about him and his desires for his children (see for example ):-
As much as I have seemed to be occupied with the work entrusted to me, I can say openly that these concerns have been secondary for me. My real life is in you and my children, who are ours, and the first form of our immortality. I'm glad to see you happy, sweet. These children are good. They take after their mother, and no quality is more important. That's the cure for all ills, for all the difficulties of life in this world, for all temptations. Keep them this way. They will work, if only for good. They will understand, as they grow, that there are people who suffer, who lack the necessities, who have neither the well-being that allows a pleasant life, nor the joys and religious and moral consolations which are the real life, and which give true happiness. They will conclude for themselves that being privileged in the midst of so many people who suffer, they must repay, through their work and dedication to others, all that they have received from society. The education they receive, they owe to the society that has well rewarded the efforts of their father. They owe much to their mother who has devoted all of her time and all of her efforts to them, and who has herself received from society noble and elevated feelings which are the most enviable charm. They will want, when their turn comes, to be good for everyone, be able to make their work render to their less fortunate fellow citizens all they have received. I have full confidence in all of them. They will never forget these feelings which seem to their father the most urgent duty, the debt I owe to others.Baillaud's lifetime of work in astronomy did not go unrecognised: in 1923, he won the Bruce Medal from the Astronomical Society of the Pacific; he was awarded the honorary degree of Sc.D. (Doctor of Science) by the University of Cambridge; there is a crater on the moon named after him (Baillaud, approved 1935) as well as the asteroids 11764 Benbaillaud and 1280 Baillauda.
Baillaud died on 8 July 1934 and has been remembered as a remarkable professor with a great amount of administrative proficiency. Four years after his death, the Alumni Association of the Middle School of Chalon-sur-Saône began work to place a bronze bust of Baillaud in the Courthouse Square. It was not actually intended for public display, but it is currently displayed in Corneilla-la-Rivière, a town in the Pyrénées-Orientales department in southern France.
Article by: I J Falconer, J G Mena, J J O'Connor, T S C Peres, E F Robertson, University of St Andrews.