This is a collection of articles written by W. Mattieu Williams on different subjects, that in his opinion "are likely to be interesting to all readers who are sufficiently intelligent to prefer sober fact to sensational fiction, but who, at the same time, do not profess to be scientific specialists." This book offers and intriguing glimpse into the scientific ideas of late 19th century. Though nowadays these essays should not be seen as wholly scientifically accurate, they are still entertaining and in many basic aspects remain truthful.