In 1899, after a students' riot in Saint Petersburg, Ossendowski was forced to leave Imperial Russia and move to Paris, where he continued his studies at the Sorbonne, his professors being Maria Curie-Skłodowska and Marcelin Berthelot. It is possible that he received a doctorate back in Russia, but no documents have survived. In 1901 he was allowed to return to Russia, where professor Zalewski invited him to the newly founded Institute of Technology of the Tomsk State University. There, he gave lectures on chemistry and physics. At the same time he also gave lectures at the Agricultural Academy and published numerous scientific works on hydrology, geology, physical chemistry, geography and physics.