The book "Scientist American. Supplement, No. 275, April 9, 1881" is a collection of scientific articles that appeared in the supplement to Scientific American magazine in April 1881. This issue contains interesting materials on the topics of physics, chemistry, biology and other scientific disciplines. The authors of the presented articles are various scientists of that time who share their research, discoveries and new ideas. This book is a valuable source of information for those interested in the history of science and technology, as well as for professionals in the field of scientific research.