It is believed by the author that a classification and presentation of selected groups of the devices produced in the past by which it was by the inventor believed, self-motive power had been attained, will save much work in fields already thoroughly exploited.
So far as the author knows no book on the subject has appeared since 1870. The various encyclopedias published contain articles on the subject, but they are necessarily brief, and not satisfying to young men who have become interested in the subject.
In 1861, Henry Dircks, a civil engineer, of London, published a work entitled "Perpetuum Mobile; or, Search for Self-Motive Power, During the Seventeenth, Eighteenth and Nineteenth Centuries." The book contains 599 pages, and was followed in 1870, by a second series by the same author entitled "Perpetuum Mobile, or a History of the Search for Self-Motive Power from the Thirteenth, to the Nineteenth Century." In these two books there is amassed a wonderful amount of material showing on the part of the author diligence, great patience and wide and thorough search.