Nikolai Fuss's mathematical abilities brought him to the attention of Daniel Bernoulli who recommended him for the post of Euler's secretary. Fuss went to St Petersburg in Russia in 1772 to take up this post and spent the rest of his life in Russia.
His first papers, written under Euler's direction, were on problems in insurance. In 1776 he became and assistant at the St Petersburg Academy and, in 1783, academician in higher mathematics. From 1800 to 1826 he was permanent secretary to the Academy.
Most of his papers are solutions to problems posed by Euler on spherical geometry, trigonometry, series, differential geometry and differential equations. His best papers are in spherical trigonometry, a topic he worked on with A J Lexell and F T Schubert.
Fuss also worked on geometrical problems of Apollonius and Pappus. He made contributions to differential geometry and won a prize from the French Academy in 1778 for a paper Recherche sur le dérangement d'une comète qui passe près d'une planète.
Fuss won other prizes from Sweden and Denmark. He contributed much in the field of education, writing many fine textbooks.