**Charles Cailler** was a Swiss mathematician who worked on differential equations and kinematics.

- After graduating from secondary school, he entered the Faculty of Sciences of the University of Geneva where he worked under the direction of professors Charles Cellérier (1818-1889) and Gabriel Oltramare (1816-1906).
- Cailler's thesis was on this topic of calculus of generalisation.
- By the age of twenty-two Cailler was a doctor of mathematical sciences having submitted the thesis Recherches sur les équations aux dérivées partielles et sur quelques points du calcul de généralisation Ⓣ(Research on partial differential equations and on some points of the generalization calculation).
- After graduating from the University of Geneva with his doctorate, Cailler undertook postdoctoral studies at the University of Berlin where he spent two years.
- At this time Berlin was a remarkable place to study mathematics with mathematicians such as Karl Weierstrass, Leopold Kronecker and Lazarus Fuchs, the latter having replaced Eduard Kummer who had retired a few years before Cailler arrived.
- In 1889 he returned to Geneva and began teaching in the Faculty of Science on 3 October, the day after the death of Charles Cellérier, holder of the Chairs of Mechanics and Astronomy.
- When in 1900 the Chair of Higher Mathematics became vacant by the retirement of Gabriel Oltramare, Cailler was also in charge of the differential and integral calculus course, which he completed by regularly teaching on the theory of functions.
- Having once again proved this theorem, Cailler extended it to the case where the density of the layer is inversely proportional of an odd (≥ 3) power to the distance of A, or to a direct one.
- For many years Cailler was a member of the Board of the Faculty of Sciences of the University of Geneva and acted as its secretary.
- Cailler was, in the full force of the term, a master of talent and of devotion.
- Dominating, to an increasingly rare degree nowadays, the different domains of mathematics, Cailler has published many memoirs of great interest pertaining to the most diverse branches, from Algebra, Geometry, Analysis, and Mechanics to the recent problems raised by the theory of relativity.
- After he retired from his teaching at the University, Cailler had made a whole plan of work.
- This was the case for Cailler.
- Cailler also had great admiration for the fine arts.
- As early as the autumn of 1921 Charles Cailler had to retire for health reasons, but his death on 30 January 1922, caused a very legitimate emotion in the scientific community.
- The life of Charles Cailler presents an admirable unity: to characterize the scientist and the professor is to let one guess what the man was.
- Cailler was a fundamentally benevolent and kind character.

Born 20 February 1865, Geneva, Switzerland. Died 30 January 1922, Geneva, Switzerland.

View full biography at MacTutor

Origin Switzerland

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive