Admitted by the Academic Committee of the Ministry of Public Education as an educational guide for secondary schools. The plan of this book was conceived by me bol? e twenty l? so on. As a beginner private associate professor at Petrograd University, I was invited to read lektsіi in mathematics? Institute? Engineer of the Way Soobshchenіya. Did I invite seb to help? in qualities?, so called, tutor of the Institute Vladimіra Andreevich Markov (academician's brother), who shortly before t? m graduated from university. Premature death of V. A. Markov of all ages? 26 l? t ot evil? her consumption deprived Russian science of its visible representative, who gave great hope.