By the end of the XIX century the Russian geographical society took an interest in Kursk magnetic anomaly and sent repeatedly the scientists to the regions for studying the reasons. There were great debates. Some say that the reason of the anomalies are unknown magnetic masses in the entrails of the earth, other scientists were closer to the truth, thinking that the underground iron-ore deposits cause the magnetic anomaly. This article reflects the work of E.E. Lejst in the study of the magnetic anomaly, a strong desire to find out the cause reasons, to discover iron-ore deposits and to obtain the mine workings in 1898-1909.