The Warsaw Scientific Society was set up by Samuel Dickstein who convened a group to try to establish the Society on 21 December 1903. Let us give a little background to this venture.
With the Polish education system controlled by the Russian rulers, Dickstein decided to do what he could to promote a Polish education and he directed his own private school for ten years beginning in 1878. However during this period he began other ventures to promote Polish science.
Dickstein was one of the main instigators of publishing mathematical journals in Poland. In 1884 he was one of the two founders of a series of mathematics and physics textbooks which were written in Polish. A few years later he was one of three scientists who set up the journal Mathematical and Physical Papers editing the journal from 1888. From 1897 he edited Mathematical News another publication which he was involved in setting up. He also continued publication of Circle of Polish Mathematicians which had begun publishing in St Petersburg in 1880. Kuratowski, thinking about the development of Polish mathematics, notes in  the importance of the publications:-
The establishment of "Mathematical and Physical Papers" and "Mathematical News" made possible for Polish mathematicians to publish the results of their research in Poland, and thus it favoured the increase of mathematical activity in our country ...In 1903 Dickstein was a founder of the Warsaw Scientific Society and he was important in the development of the Polish Mathematical Society. The first meeting of a group trying to set up a Polish institution in Warsaw took place on 21 December 1903. Dickstein was one of two mathematicians in this founding group of fourteen, and was elected as secretary of the group. The work of the Warsaw Scientific Society started properly in November 1907. A Mathematical Study was set up with Dickstein donating a fine library of mathematical texts.
Despite the fact that the Polish Mathematical Society was set up in 1919, the Warsaw Scientific Society continued to play a major role in mathematics. For example in 1928 Sierpinski was elected vice-chairman of the Warsaw Scientific Society.
List of References (2 books/articles)
Other Web site Society Web-site (in Polish)