The Scientific American Supplement, published from 1876 to 1924, was a weekly publication that provided in-depth articles on a wide range of scientific and technological topics. It was a companion to the Scientific American, which published shorter, more popularized articles. The Supplement was intended for a more specialized audience, including scientists, engineers, and other professionals. It covered a wide range of topics, including astronomy, physics, chemistry, geology, biology, medicine, and engineering.