N Newton’s Principia

Newton’s Principia

Marlborough College is fortunate to own a copy of the rare and important second edition of Newton’s Philosophiae naturalis principia mathematica (1713), one of only 750 copies printed.

It contains substantial modifications to the text of the extremely scarce first edition of 1687, of which only 250 copies were made. Published 26 years after the first, the second edition was printed at Cambridge University Press in wide quarto format and illustrated with numerous woodengraved and letterpress diagrams, including beautiful images of cometary orbits. Newton’s work had a major influence on the history of science, and was described by Albert Einstein as ‘perhaps the greatest intellectual stride that it has ever been granted to any man to make’.

There were, in all, three authorised printings of the Principia in Newton’s lifetime (1643–1727). Richard Bentley, the Cambridge classical scholar and member of the Royal Society, noticed that copies of the first edition were becoming increasingly hard to find and accordingly very expensive. In 1708 he convinced his friend Newton to allow him to organise a second edition, and to engage the help of Roger Cotes, Professor of Astronomy at Cambridge, in compiling it. Together, they expanded the scope of the work and developed further postulations. The result was an improved and expanded text of the Principia; indeed, the book was almost entirely rewritten. The second edition of the Principia was subsequently viewed as an exemplary work of empirical science, and the definitive expression of Newton’s ideas. Because of the extent to which Einsteinian theory is grounded on Newtonian science, the Principia has retained its unique and seminal position in the history of physics, even if some of its tenets have been further refined and finessed.

Philosophiae naturalis principia mathematica translates from Latin as ‘Mathematical Principles of Natural Philosophy’, the term ‘natural philosophy’ being an earlier description of what we would call physics. The book expounds Newton’s laws of motion and universal gravitation, making it the foundational work of classical mechanics. The sequence of definitions used in setting up dynamics in the Principia is familiar from many textbooks current today. Indeed, Newton first set out the definition of mass used to define what we now call momentum. Newton’s single-minded attention to his work on the Principia was recalled many years later by his one-time secretary and copyist, Humphrey Newton (no relation). His account describes his master’s complete absorption in his studies, and how he would forget to eat or sleep, and that he would often rush back to his room with a new thought, not even waiting to sit down before writing.

The College’s copy of the Principia is imperfect, lacking its title page. It is bound in early 19th-century calf with neoclassical ornament and bears an old ex libris of the library of the Mathematics Department. How one of the first thousand copies of science’s most momentous book since antiquity came into College ownership is unknown.