Kazimierz Marcin Sosnowski (1857-1942), born in the village of Wincentów (Kolno district, Łomża gubernia), son of Kalikst Sosnowski (member of the municipal organisation in 1863, owner of a tenement house in Łomża) and Karolina Godlewska. A graduate of the Technological Institute (Polytechnic) in St Petersburg, he did not, however, receive his diploma, according to the PSB. During and after his studies, he was ideologically linked to the socialist movement, for which reason he fled the Kingdom of Poland via Galicia and Switzerland, eventually settling in France. He was a technological engineer, foreign trade advisor and member of the Paris Chamber of Commerce. He published many works, especially on steam engines, director of the Laval system steam turbine company, one of the founders of the steam turbine industry. Author of numerous political pamphlets and proclamations and the book La turbine à vapeur de Laval (published 1895). He married Helena Goldszpigel (Goldszpiegel, Golspiegel) on 21 August 1890 in Paris (AdP AM Paris 8e no. 717 of 1890). Naturalised in France with his wife and son on 1 January 1900. He died on 7 February 1942 in Paris at his place of residence (13 rue Clément-Marot), and was buried on 10 February 1942 (annual number 366) (AdP AD Paris 8e, no. 141 of 1942; ANF Leonore database, code LH 19800035/251/33465).

• Polski Słownik Biograficzny, t. 40, s. 575–579