I have now reviewed the context of Han astronomy so far as it relates to the Zhou bi, and tried to show how the contents and origin of the book can be understood within that context. From the Han dynasty onwards the nature of our discussion changes, for the Zhou bi is no longer the property of an active group of astronomical thinkers, but becomes a classical text subject to the labours of commentators and editors.

So far it has been necessary to be cautious in speaking of ‘the Zhou bi’, for we have had no guarantee that the term referred to anything that had yet taken on a fixed form and content. If my tentative explanation of the process by which the canon was closed is correct, the Zhou bi waited at least two centuries before Zhao Shuang saw it, and in that interval it certainly seems that the text suffered some damage and corruption. But a careful reading of the present text and its three commentaries suggests that since the time of Zhao the text has not changed apart from a few minor copyist's errors. The object of this section is to tell the story of how the Zhou bi came down to the present day. In the process it will be interesting to say something about its later influence, without becoming too involved in the historical complexities of pre-modern Chinese debates on astronomy and cosmography.

The Zhou bi in the period of division

From the break-up of the Han in AD 220 to the reunification under the Sui in AD 581, China underwent three centuries of division and political chaos.

Most previous discussions of the Zhou bi have at some point attacked the apparently obvious question of the date of the work. A recent study cites the opinions of fourteen scholars before coming to its own conclusion that ‘Therefore, the date of composition of the work must be in the early Western Han (c. 200 BC).’ We may note that the opinions cited give dates ranging from the traditional attribution to the Duke of Zhou in the eleventh century BC to the conclusions of a modern scholar that the book can be precisely bracketed into the period AD 9 to AD 84.

I do not intend to provide such a review of the work of all previous scholars on this topic before beginning my own discussion. My reasons for this are twofold. Firstly, and fairly trivially, a critical review of fourteen different opinions (each it must be said written with little or no reference to the others) is probably not the best way to help the reader towards clarity of mind on this question. More importantly, I believe that previous writers on this topic have largely misdirected their efforts in trying to find some epoch when the book as a whole could reasonably have been composed.

I suggest that two unspoken assumptions behind these efforts have lead to largely illusory results being obtained. Firstly, it is assumed that the Zhou bi is more or less a single entity which must therefore have some particular date of composition. I believe that on the contrary the different sections of the Zhou bi have extremely varied degrees of interrelation.

I have endeavoured here to write an account of the greatest mind in British history. If any names of Englishmen survive into the remote future, those of Shakespeare and Newton will surely be among them. The latter was above all things a mathematician and a natural philosopher, but he also gave deep scholarship and profound thought to ancient history, especially to the early history of Christianity, the unravelling of sacred prophecy and even to monetary theory and practice. On all these topics he left vast accumulations of manuscript material.

In this book attention is chiefly directed to Newton the mathematician and philosopher. As such he worked his great transformation in human thought. Even so, a volume of modest size permits no very technical treatment of his researches in mathematics and mechanics, and in experimental optics. For such treatment the reader may turn to D. T. Whiteside's epoch-making edition of Newton's Mathematical Papers, the parallel volumes of Optical Papers (in progress) edited by Alan E. Shapiro, and very many specialist studies by these and other scholars. As for Newton's daily life and personal pursuits, for all the huge amount of material by and concerning Newton now accessible to us, these are shadowy at all periods of his life. I have not tried to emulate here Frank E. Manuel's psychological analysis of Newton in terms of theories whose validity seems to be doubtful. In general, I believe it imprudent to try to interpret Newton's life and writings in terms of single factors, whether these be his infantile experiences, his reading of the strange books of the alchemists, his faith in God or even his confidence in number and measure.

Humphrey Newton's Recollections

In the last year of the reign of King Charles II, according to his own recollection, Humphrey Newton came to Trinity College, Cambridge, from Grantham School to be sizar to his great namesake, Isaac. Neither Newton admitted or claimed relationship with the other. Humphrey remained with Isaac for five years before returning to Grantham as a country physician, during which period he lived in some intimacy with the Lucasian Professor, chiefly serving as his copyist. John Conduitt, after Isaac's death, sought in 1728 Humphrey's recollections of him, first published by Brewster in 1855. With all its obvious imperfections and silliness, Humphrey's is the only personal record of Newton's daily life from someone who had every opportunity for close and long observation.

Humphrey was much more struck by Newton's manners than by his mind, which was beyond his appreciation. His only memory of the Principia, after having copied it, was that some of the scholars in Cambridge to whom Newton bade him take presentation copies, declared ‘that they might study seven years before they understood any thing of it’. (They might have spent seven years in worse ways.) He remembered that Newton kept a five-foot-long [refracting] telescope at the head of the stairs leading from his rooms to the garden below, but all he could say of Newton's study of astronomy was that ‘several of his observations about comets and the planets may be found scattered here and there in a book entitled The Elements of Astronomy by Dr. David Gregory.’