"La Photographie Animée" by Eugène Trutat, Director of the Natural History Museum in Toulouse, is a 1899 publication that explores the history and development of animated photography. The book is introduced by a preface by Marey, a renowned chronophotographer. The author begins with a brief history of the subject, explaining the application of persistence of vision in early devices like the phenakisticope and zootrope. He then traces the evolution of the apparatus from multiple cameras of Muybridge, Anschutz, Londe, and himself to the use of fixed plates by Marey and others. The book includes detailed descriptions of French machines that have been successful. The third chapter discusses the procedures for obtaining and displaying photographs, including exposure, development, and printing. The book is useful for those interested in animated photography, though its value is somewhat limited by its focus on French apparatus and lack of knowledge about foreign machines. The article discusses the interferometer and the use of the device in high interference observations. It addresses concerns about diffraction and the visibility of interference bands, and explains the structure of the spectrum line. The author describes modifications to the original apparatus to improve performance, using a fluid surface as a reflector. The article also discusses the theory of functions, responding to criticisms from Prof. Burnside. The authors clarify that their work is accurate and that the reviewer's criticisms are based on misunderstandings. They also correct the reviewer's misstatement about the number of chapters on elliptic functions and the definition of logarithms. The article discusses the tetravalency of oxygen, arguing that oxygen is tetravalent in certain compounds and that this concept is important for understanding the alternating valency of non-metallic atoms. The author references historical predictions about polymerization and the role of oxygen in chemical reactions. The article discusses the progress of wireless telegraphy, highlighting the achievements of Marconi and the potential of the technology for future communication. It emphasizes the importance of the technology for maritime communication and the need for regulations to prevent interference."La Photographie Animée" by Eugène Trutat, Director of the Natural History Museum in Toulouse, is a 1899 publication that explores the history and development of animated photography. The book is introduced by a preface by Marey, a renowned chronophotographer. The author begins with a brief history of the subject, explaining the application of persistence of vision in early devices like the phenakisticope and zootrope. He then traces the evolution of the apparatus from multiple cameras of Muybridge, Anschutz, Londe, and himself to the use of fixed plates by Marey and others. The book includes detailed descriptions of French machines that have been successful. The third chapter discusses the procedures for obtaining and displaying photographs, including exposure, development, and printing. The book is useful for those interested in animated photography, though its value is somewhat limited by its focus on French apparatus and lack of knowledge about foreign machines. The article discusses the interferometer and the use of the device in high interference observations. It addresses concerns about diffraction and the visibility of interference bands, and explains the structure of the spectrum line. The author describes modifications to the original apparatus to improve performance, using a fluid surface as a reflector. The article also discusses the theory of functions, responding to criticisms from Prof. Burnside. The authors clarify that their work is accurate and that the reviewer's criticisms are based on misunderstandings. They also correct the reviewer's misstatement about the number of chapters on elliptic functions and the definition of logarithms. The article discusses the tetravalency of oxygen, arguing that oxygen is tetravalent in certain compounds and that this concept is important for understanding the alternating valency of non-metallic atoms. The author references historical predictions about polymerization and the role of oxygen in chemical reactions. The article discusses the progress of wireless telegraphy, highlighting the achievements of Marconi and the potential of the technology for future communication. It emphasizes the importance of the technology for maritime communication and the need for regulations to prevent interference.