THE idea of using the concave surface of an umbrella as a star map is excellent, but, of course, not new. The portability and convenience of manipulation of such a stellar guide are obvious advantages ...

THIS volume is, avowedly, not so much a text-book for astronomical students as “an invitation to read text-books on the subject,” but while it contains a large amount of real information, we fear that ...

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in ...