Among the concepts originated by Newton and appearing in the Principia, the most important is no doubt "mass," introduced and named in Definition 1 of the Principia. In this work there are also set forth the three "Laws of Motion," generally known today as "Newton's laws." Here also is the first appearance in print of Newton's invention of the calculus, the universal tool of the exact natural and social sciences.

What most attracted attention and admiration in the century after Newton's book was published, however, was not his magisterial contributions to the new science of dynamics or his presentation of the differential calculus, but rather his "System of the World," an explanation of the phenomena of our universe based on "scientific" principles-a gravitational cosmology. Here was a magnificent display of the power of the human mind strengthened and guided by science. Most people agreed with Sir Edmond Halley's judgment (in a poem he wrote as a kind of foreword to the Principia): "No mortal may approach nearer to the gods!"

The Editions
The Principia was published during Newton's lifetime in three authorized editions: London, 1687; Cambridge, 1713; and London, 1726. During this time there were also two unauthorized editions: Amsterdam, 1714; Amsterdam, 1723. The first edition occurs in two "states," differentiated by the title page. The first (or original) bears the imprint "apud Sa. Smith." The title page of the second state is a cancel, pasted on the stub of the original, or cancellandum; it bears the imprint "apud Sam. Smith … aliosque nonnullos Bibliopolas." It was suggested by A. N. L. Munby, the first scholar to undertake a careful bibliographical study of these two states, that copies in the second state were intended for sale on the Continent. Munby estimated that this first edition was limited to between two-hundred and fifty and three hundred copies of the first issue and about fifty of the second; more recently D. T. Whiteside has shown that the more likely number was five hundred. The second edition (1713) occurs only in a single state; the size of the edition was seven hundred and fifty copies. The third edition (1726) exists in three states. Most of the copies were printed on ordinary sized paper; a certain number were printed on "large paper;" and a very few on extra large paper ("royal folio'). The number of copies printed in these three states were as follows: 800, 25, 10.

The Babson Collection has a copy of each of these authorized editions: 1687 (both states); 1713; 1726 (all three states). Thus in a single collection are every form of every edition of the Principia published before Newton's death in 1727.

A Very Special Copy
The Collection also contains a very special copy of the first edition, formerly in the possession of Miss Margaret Norman of Cremorne (New South Wales, Australia). This copy had been in the library of her great-grandfather, James Sprent, an
Edinburgh astronomer who migrated to Hobart in 1837, and later became Surveyor-General of Tasmania. This copy has a contemporaneous calf binding, containing a tool in gold in the corners, which differs from the tool (in blind) in the three copies known to have been presentations by Newton (at present in the Sidney Sussex and Trinity libraries, Cambridge-one of the two in Trinity is the copy presented by Newton to John Locke). The title page of the Babson Collection's copy bears an inscription, partly in Greek and partly in Latin, which may be translated as:

A remembrance of the
cherished person of a most
outstandingly learned and
distinguished Author.

The handwriting is that of Sir Edmond Halley and the inscription almost identical to one in a copy of Newton's Opticks (1704) that also belonged to Halley. This copy of the Principia is especially noteworthy because of the corrections to the text, mostly made by Halley himself. In the years following the publication of the Principia, Newton produced a number of corrections and improvements that were quite widely disseminated. These are described and listed in the Latin edition of the Principia with variant readings (Edited by A. Koyré, I. Bernard Cohen, and Anne Whitman, 1971, vol. 2, suppl. 4; see "Introduction to the 'Principia,'" 1070, p. 202). What is especially remarkable about the Babson copy is that at least six of the alterations were made by Newton himself, in his own hand and appear in other annotated copies of the first edition. In the laudatory poem written by Halley, he himself suggested that the word ulva (in the accusative ulvam or "sedge") be changed to alga ("seaweed").
    One of the puzzles of this copy is that it is printed on a thick paper, much coarser than the paper generally found in other copies of the first edition. This copy came to the Babson Collection, following an auction at Sotheby's, through Dawsons of Pall Mall. In Dawsons' catalogue, Eric Osborn, then their chief cataloguer, described this as a "proof copy" largely because it is printed on coarse paper. This cannot be true. A comparison of the text of this copy and the manuscript used by the printer shows that it is of later date than the proof copy. Furthermore, there are no proof corrections preliminary to publication. The difference in paper remains a mystery.