Today I have been mildly irritated by numerous tweets announcing the 5th July 1687, as the day on which Isaac Newton’s Principia was published, why? Partially because the claim is not strictly true and partially because it evokes a false set of images generated by the expression, published on, in the current age.
In the last couple of decades we have become used to images of hoards of teens dressed in fantasy costumes as witches queuing up in front of large bookstores before midnight to participate in the launch of the latest volume of a series of children’s books on a juvenile wizard and his adventures. These dates were the days on which the respective volumes were published and although the works of other authors do not enjoy quite the same level of turbulence, they do also have an official publication date, usually celebrated in some suitable way by author and publisher. Historically this has not always been the case.
In earlier times books, particularly ones of a scientific nature, tended to dribble out into public awareness over a vague period of time rather than to be published on a specific date. There were no organised launches, no publisher’s parties populated by the glitterati of the age and no official publication date. Such books were indeed published in the sense of being made available to the reading public but the process was much more of a slapdash affair than that which the term evokes today.
One reason for this drawn out process of release was the fact that in the early centuries of the printed book they were often not bound for sale by the publisher. Expensive works of science were sold as an unbound pile of printed sheets, allowing the purchaser to have his copy bound to match the other volumes in his library. This meant that there were not palettes of finished bound copies that could be shipped off to the booksellers. Rather a potential purchaser would order the book and its bindings and wait for it to be finished for delivery.
Naturally historians of science love to be able to nail the appearance of some game changing historical masterpiece to a specific date, however this is not always possible. In the case of Copernicus’ De revolutionibus, for example, we are fairly certain of the month in 1543 that Petreius started shipping finished copies of the work but there is no specific date of publication. With other equally famous works, such as Galileo’s Sidereus Nuncius, the historian uses the date of signing of the dedication as a substitute date of publication.
So what is with Newton’s Principia does it have an official date of publication and if not why are so many people announcing today to be the anniversary of its publication. Principia was originally
printed written in manuscript in three separate volumes and Edmond Halley, who acted both as editor and publisher, had to struggle with the cantankerous author to get those volumes out of his rooms in Cambridge and into the printing shop. In fact due to the interference of Robert Hooke, demanding credit for the discovery of the law of gravity, Newton contemplated not delivering the third volume at all. Due to Halley’s skilful diplomacy this crisis was mastered and the final volume was delivered up by the author and put into print. July 5th 1687 is not the date of publication as it is understood today, but the date of a letter that Halley sent to Newton announcing that the task of putting his immortal masterpiece onto the printed page had finally been completed and that he was sending him twenty copies for his own disposition. I reproduce the text of Halley’s letter below.
I have at length brought you Book to an end, and hope it will please you. the last errata came just in time to be inserted. I will present from you the books you desire to the R. Society, Mr Boyle, Mr Pagit, Mr Flamsteed and if there be any elce in town that you design to gratifie that way; and I have sent you to bestow on your friends in the University 20 Copies, which I entreat you to accept.
 Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, Cambridge University Press, Cambridge etc., 1980, p. 468.