The Whetstone of Witte. Este artículo no está disponible.The Whetstone of Witte

The sole edition of Robert Recorde's The Whetstone of Witte was printed at London by John Kingston in 1557. One of Recorde’s concerns in this book is to develop not only a means of representing powers of numbers, but also a means of naming them. Prior to the development of a numerical index notation, the names given to the powers was of considerable importance. Hence in these pages we find terminology which is now archaic, for instance the strange word zenzizenzizenzike, the name for the eighth power of a number. It is generally acknowledged that Recorde’s treatise on algebra, in the section entitled The arte of cossike numbers, is the first to be printed in the English language. Although this work owes much to the German mathematicians Christoff Rudolff and Michael Stifel, it does have one well known claim to originality; the first use of two parallel lines as the sign for equality (because noe 2 thyngs, can be moare equalle). Recorde’s invention of the equals sign =, together with his adoption of the + sign (which betokeneth more) and the minus sign – (which betokeneth less) placed him at the very forefront of European practice. Like most of Recorde’s books, The Whetstone is written in the form of a dialogue between a learned master and a clever, but rather precocious, scholar. After being patiently encouraged through the seconde parte of arithmetic (begun by the scholar in Recorde’s first book, The Grounde of Artes) followed by the extraction of rootes, the scholar remarks ‘I am moche bounde unto you … Trusting so to applie my studie, and emploie my knowlege, that it shall never repente you of your curtesie in this behalfe’. To which the master, about to start an exposition on the difficult and strange cossike arte (algebra), replies ‘Then marke well my words, and you shall perceive, that I will use as moche plainesse, as I maie, in teaching : And therefore will beginne with cossick numbers first’. Here Recorde is again using terminology that is now archaic. In his day algebra was called the cossic art, derived from the Latin cosa, meaning ‘thing’. The Whetstone also includes a lengthy treatise on the arte of surde nombers, that is, on irrational numbers.

Robert Recorde was born circa 1510 in Tenby, Pembrokeshire, Wales. He entered Oxford University in 1525 aged about 15 years. He graduated with a B.A. in 1531 and was elected a Fellow of All Souls College in the same year. At some time he moved from Oxford to Cambridge, where he studied for an M.D. and graduated in 1545 at the age of 35. He then moved to London, where for a few years he practised medicine. In later years he was always to describe himself as 'physician' and was judged as a very learned scholar. A defining moment in his life occurred in 1549 when he was appointed Controller of the Bristol Mint. It was during his time there that he made a very powerful and ruthless enemy. Sir William Herbert was sent by Edward VI to help suppress a revolt by John Dudley, Earl of Warwick, in the west country. Herbert demanded that Recorde divert funds from the mint to pay and support his army, but Recorde refused on the grounds that the order did not come from the king. Herbert countered and accused Recorde of treason. He was lucky to incur the mild penalty of confinement to court for 60 days. However, apparently all was later forgiven because in 1551 he was appointed general surveyor of Mines and Monies in Ireland. He was placed in charge of the Wexford silver mines and also became the technical supervisor of the Dublin mint. In the meantime, Sir William Herbert was created Earl of Pembroke for his services to the crown during the rebellion, and there was continued animosity between him and Recorde. Upon the accession to the throne of Mary, the daughter of Henry VIII, Pembroke was made a privy councillor for his support of Mary's claim to the throne. For some strange reason, Recorde chose the moment when Pembroke was strongest to try and get his revenge, charging him with misconduct in gaining his court positions. The allegation was probably true, but Pembroke was in favour with the monarchy and so had almost perfect immunity. He responded by suing Recorde for libel. There was a hearing in January 1557 and Recorde was ordered to pay the huge sum of £1000 compensation. He either could not or would not pay and so was sentenced to imprisonment in the King's Bench Prison in Southwark, for debt. Whilst in prison he made his will, leaving small sums of money to various people, including £20 to his mother. The date of his death is not known with any certainty, but is generally supposed to have been in the later part of 1558, only a short time after making his will.