The book "Scientific American Supplement, No. 803, May 23, 1891" is a publication that contains unique materials from various fields of science and technology. In this issue you will find interesting articles about the latest discoveries and achievements in science, new inventions and technologies of our time. Readers will have the opportunity to deepen their knowledge of various disciplines and get acquainted with the prospects for the development of science at the beginning of the 20th century. Scientific American will become an important source of information for anyone interested in 19th century science and technology.