"The popular science supplement to the edition of Scientific American, No. 520, dated December 19, 1885, invites readers on an exciting journey into the world of science and technology of the 19th century. This issue collects articles from authors in various scientific fields, allowing you to review the latest research and discoveries Famous scientists share their discoveries and findings with readers, revealing the secrets of nature and technological achievements of the time. Scientific American Supplement, No. 520 is a window into the world of science of the 19th century, inviting you on an exciting intellectual journey."