Louis Néel's article "Some Theoretical Aspects of Rock-Magnetism" explores the magnetic properties of rocks, focusing on ferrimagnetism, single-domain particles, and multi-domain particles. The paper discusses the behavior of magnetic minerals in rocks, such as magnetite, titanomagnetites, and maghemite, and their interactions with external magnetic fields. It covers the thermal variation of magnetization, the role of magnetic viscosity, and the effects of demagnetizing fields. The article also examines the reversal of spontaneous magnetization in ferrites, the compensation temperature, and the Curie point. It provides a detailed analysis of the magnetic properties of various rock constituents, including the effects of temperature, composition, and structural changes on magnetization. The study highlights the importance of understanding these properties for interpreting the magnetic behavior of rocks in geological contexts. The paper is divided into sections discussing different aspects of rock magnetism, including the theoretical foundations of ferrimagnetism, the behavior of single-domain and multi-domain particles, and the experimental and theoretical results related to magnetic properties of rocks. The article concludes with a discussion of the implications of these findings for the broader understanding of rock magnetism and its applications in geophysics.Louis Néel's article "Some Theoretical Aspects of Rock-Magnetism" explores the magnetic properties of rocks, focusing on ferrimagnetism, single-domain particles, and multi-domain particles. The paper discusses the behavior of magnetic minerals in rocks, such as magnetite, titanomagnetites, and maghemite, and their interactions with external magnetic fields. It covers the thermal variation of magnetization, the role of magnetic viscosity, and the effects of demagnetizing fields. The article also examines the reversal of spontaneous magnetization in ferrites, the compensation temperature, and the Curie point. It provides a detailed analysis of the magnetic properties of various rock constituents, including the effects of temperature, composition, and structural changes on magnetization. The study highlights the importance of understanding these properties for interpreting the magnetic behavior of rocks in geological contexts. The paper is divided into sections discussing different aspects of rock magnetism, including the theoretical foundations of ferrimagnetism, the behavior of single-domain and multi-domain particles, and the experimental and theoretical results related to magnetic properties of rocks. The article concludes with a discussion of the implications of these findings for the broader understanding of rock magnetism and its applications in geophysics.