Thomas Hobbes and ‘The Mathematical Demonstration of the Sword’

IAmong the Harleian manuscripts in the British Library sits a brief treatise entitled 'The mathematical demonstration of the sword' (MS 5219). The text of this little tract covers a mere seven pages, with two pages of printed diagrams. It sets about a mechanical analysis of the relative force of two swords pressing against one another, with a view to providing new principles for use in attack and defence. The treatise has attracted little attention; the only printed notice known to me is that of Thimm, who lists it among anonymous manuscript works in his bibliography of fencing manuals.1 But although it may be anonymous, it is attributable: it is an otherwise unknown work by Thomas Hobbes.The text is written in Hobbes's hand.2 It reveals all the distinctive features of his script, including those by which it may be distinguished from the similar hand of his friend, Robert Payne: these include paragraphing by means of spacing rather than indentation; ascenders and descenders thickened by means of tightly-looping pen-strokes; the absence of Greek e, but the presence of italic, reversed secretary, and two-stroke e; and a sharply angled foot on l.3 (See fig. A.)Why should Hobbes, so renowned for his horror of physical confrontation, have composed an essay on the force of two swords? To answer that question we must determine the context in and the purpose for which the essay was written.The essay was presented to and was, I shall demonstrate, written for Hobbes's patron, William Cavendish, marquess of Newcastle.4 Newcastle has, in fact, endorsed the manuscript, on its first folio, 'The [>mathematicall] Demonstration off The Sorde'. This allows us to connect it with his own autograph treatise, 'The Truth off the Sorde', also in the Harleian Collection (MS 4206), because near the start of that treatise, Newcastle inscribed the instruction 'The nexte This muste bee the mathematicall demonstration off The Sorde'.5 Hobbes's demonstration was therefore to have been incorporated into Newcastle's text. In order to make sense of this extraordinary situation, we need to sketch out some background on Newcastle and his treatise.Newcastle's expertise as a horseman is well known: it was celebrated in an epigram by Ben Jonson, and his 'new method' of dressage is widely believed to have contributed much to modern haute ecole.6 It is, however, less widely known that Newcastle was also an avid and adept swordsman - despite the fact that Jonson also wrote an epigram celebrating his proficiency at that 'noble Science'.7 In her biography of her husband, Newcastle's wife, Margaret, furnishes us with an explanation for the tendency to neglect his interest in swordsmanship, by distinguishing his relatively public demonstrations of his method of horsemanship (in which he personally instructed his 'escuyers') from his more private demonstrations of swordsmanship, in which he also developed a 'new method': 'But in the art of weapons (in which he has a method beyond all that ever were famous in it, found out by his own ingenuity and practice) he never taught anybody but now the Duke of Buckingham, whose guardian he hath been, and his own two sons.'8 In fact, Newcastle's treatise, 'The Truth off the Sorde', was addressed to his sons.9 Another reason for this neglect is that, unlike his manuals on the manage, Newcastle's treatise on the use of the sword was never published.Newcastle's treatise covers some ninety-five folios on sheets of large, highquality paper. The volume is fairly written in Newcastle's autograph, but is not a fair copy. Instructions for insertions at various points in the text, and Newcastle's provision of verses to accompany a non-existent frontispiece indicate either that it was to be recopied or that it was to be printed. Given its address, inter alia, 'To all Noble Caualiers, [>&] Gentle-men off the Sorde', it seems safe to assume it was intended for the press, in the same manner as his manuals on horsemanship of 1658 and 1667. …