Equations for Mutual Inductance of Coaxial Circles

Professor Joseph Henry (1797-1878), a towering figure in American science and the first Secretary of the Smithsonian Institution, left an indelible legacy of intellectual brilliance and exemplary character. His pioneering research in electromagnetism, particularly his development of high-intensity magnets and long-distance signal transmission, laid the foundational science for the electric telegraph, though he prioritized pure discovery over personal commercial gain. As Secretary of the Smithsonian for over three decades, Henry meticulously shaped its mission for \"the increase and diffusion of knowledge among men,\" ensuring its global relevance, financial integrity, and avoiding duplication of efforts. He was celebrated for his profound wisdom, humility, and unwavering Christian faith, which he harmoniously integrated with scientific inquiry, viewing the study of nature as a form of worship and seeing a divine creator in natural laws. His life exemplified selfless service, dedicating himself to scientific advancement and public institutions, including the Light-House Board, earning him widespread national and international acclaim. Memorialized by presidents, Supreme Court justices, congressional leaders, and scientific bodies in unprecedented gatherings, and honored with a special memorial volume, Henry's enduring impact on technology, scientific institutions, and the harmonious integration of science and faith continues to inspire, solidifying his place as a \"father of American science\" and a \"Christian gentleman.\