The Mechanism of the Heavens was the first english language "rendition" of Pierre Simon Laplace's five volume Mécanique céleste. In this work Somerville, who was later known for her predition of the then undiscovered planets Neptune and Pluto, introduced continental mathematics to english speaking readers for the first time This led to a revolution in mathematics in the UK, beginning at Cambridge University where the Mechanism of the Heavens became a standard text in courses on higher mathematics.

This second edition of Mechanism of the Heavens is designed to address not only its scarcity, but several deficiencies in the first edition. These include the correction of 140 reported errata and a significant number of unreported errata in the 1831 edition. The unreported errata include obvious printing errors such as page repeats, mislabeled chapters, and obvious printing related mathematical errata. All changes to the text have been clearly identified and the original expressions included in notes at the end of each chapter. We have made no attempt to challenge the mathematical integrity of this work. The Critical Reviews written in 1832 and included in this second edition clearly document the importance of the original text in altering the trajectory of 19th century mathematics in the English speaking world. This annotated second edition includes short biographies of numerous 19th century mathematicians and scientists referred to in the first edition (most of whom were known to Somerville). New non-mathematical annotated Forewords to each of the four Books of Mechanism of the Heavens are drawn exclusively from Somerville's own clear writing on selected topics in Celestial Mechanics published in the 10th and final edition of her popular text On the Connexion of the Physical Sciences (1877). Somerville, who was completely self taught, was considered as one of only a handful of english speaking mathematicians able to undertake this work and was praised lavishly by many of the leading scientists, mathematicians and other intellectuals of her day including James Clerk Maxwell, Charles Darwin, Michael Faraday, Sir Charles Lyell and John Stuart Mill. The work is divided into four major books on Dynamics, Universal Gravitation, Lunar Theory, and The Satellites of Jupiter. The substantial Preliminary Dissertation together with the new Forewords to each book provide the non-technical reader sufficient background to appreciate the significance of this work. The appendicies include four contemporary critical reviews, a revised subject index and a new name index.

The editor is indebted to the assistance provided by Somerville College, Oxford, during the research phase of this project. College Librarian and Archivist Ms. P. Adams was generous in providing advice and materials. College Secretary Ms. Norma MacManaway and Ms. Anne Wheatley provided access to College resources and accommodation and Mr. Chris Bamber provided computer assistance. I would also like to extend my appreciation to Professor A. Morpurgo Davies for additional direction. The archivists, librarians and staff of the Bodleian Library, Oxford, were especially helpful and generous in answering many questions and providing free access to the Mary Somerville Collection and related documents. The more than 5,000 items in that Collection were sorted and catalogued by Elizabeth Chambers Patterson beginning in 1967. That archival work culminated in the publication in 1983 of her extraordinarily thorough Mary Somerville and the Cultivation of Science 1815-1840, an invaluable source for students of Mary Somerville. Cambridge University Press has also released a new publication on Somerville by Kathryn A. Neeley. This important work Mary Somerville : Science, Illumination, and the Female Mind offers new insight on the character of this extrordinary 19th century intellectual.

Russell McNeil, Ph.D.
Department of Physics, Engineering and Astronomy and,
Department of Liberal Studies
Malaspina University College