Joseph Chaix Isniel was born in San Felipe (now Xátiva) in 1765; he was interested in mathematics and astronomy. He studied at the University of Valencia and continued his studies in Britain and France.

He was among the Spanish scholars living in Paris who worked at the service of the Spanish Crown, under the leadership of Agustín de Betancourt. Before leaving Paris, between 1791 and 1793, Chaix was commissioned by the Spanish government to join a group of French scientists who had been appointed to carry out measurements of a meridian arc on Spanish soil, led by Jean Baptiste Delambre and Pierre Méchain, participating in the project along with Juan López de Peñalver.

In 1795 he was appointed vice-director of the Observatory of Madrid and the following year, when Salvador Ximenez Coronado created the Corps of Cosmographic Engineers, Chaix was appointed vice-director. When Coronado Ximenez resigned, he became Director of the Corps. He was later commissioner of the General Inspection of roads and canals, and was responsible for one of the chairs of the School of Roads and Canals, directed by Agustín de Betancourt.

In 1803, he collaborated again with Méchain with the mission of extending the measurement of the meridian arc to the Balearic Islands, work that continued until Méchain’s death in 1804. This work began again in 1806 under the command of Jean Baptiste Biot and Francois Jean Dominique Arago and was again interrupted, this time for good, by the War of Independence.

There is a certain parallelism between the determination of the metre and the early works on optical telegraphy, both chronologically and by the people involved or the elements they had in common, such as the use of telescopes and the need to have stations with visual communication between them. The report of Borda and Delambre (among others) on Betancourt's telegraph is well known, the first of them was the inventor of the "repeating circle" an instrument used by Delambre and Méchain to carry out their measurements. But not so well known is the proposal of a direct collaborator of Pierre Méchain (responsible for the measurement of the arc) of an optical telegraph system in Spain.

In 1809 Chaix, was commissioned by the Junta Central Suprema to give his opinion on the proposal of a telegraph devised by the Franciscan Soler y Sintes. The ruling was not favourable, but Chaix with the priest Miguel Pla, pledged to develop another system using the expertise of the mathematician. Chaix system was based on Murray’s Shutter Telegraph that he had seen during his stay in England and it consists of six shutters that can be opened or shut independently, giving rise to a primitive binary code.

Joseph Chaix is one of the few mathematicians of the late eighteenth and early nineteenth century internationally recognized thanks to his first volume of Instituciones de Cálculo Diferencial e Integral (Differential and Integral Calculus Institutions), published in 1801. He also published several astronomical works in the journal "Anales de Ciencias Naturales" and in 1807 he published Memoria sobre un nuevo método general para transformar en serie las funciones trascendentes (Report on a new general method to transform the transcendental functions into series).