then good speed, went about to preocupate.” It was this passage which started the conflagration. Another pupil, W. Robinson, wrote to Oughtred, when the latter was preparing his Apologeticall Epistle as a reply to Delamain’s countercharges: “Good sir, let me be beholden to you for your Apology whensoever it comes forth, and (if I speak not too late) let me entreat you, whip ignorance well on the blind side, and we may turn him round, and see what part of him is free.”[52] As stated previously, Oughtred’s circular slide rule was described by him in his Circles of Proportion, London, 1632, which was translated from Oughtred’s Latin manuscript and then seen through the press by his pupil, William Forster. In 1633 appeared An Addition vnto the Vse of the Instrvment called the Circles of Proportion which contained at the end “The Declaration of the two Rulers for Calculation,” giving a description of Oughtred’s rectilinear slide rule. This Addition was bound with the Circles of Proportion as one volume. About the same time Oughtred described a modified form of the rectilinear slide rule, to be used in London for gauging.[53] CHAPTER III MINOR WORKS Among the minor works of Oughtred must be ranked his booklet of forty pages to which reference has already been made, entitled, The New Artificial Gauging Line or Rod, London, 1633. His different designs of slide rules and his inventions of sun-dials as well as his exposition of the making of watches show that he displayed unusual interest and talent in the various mathematical instruments. A short tract on watchmaking was brought out in London as an appendix to the Horological Dialogues of a clock- and watchmaker who signed himself “J. S.” (John Smith?). Oughtred’s tract appeared with its own title-page, but with pagination continued from the preceding part, as An Appendix wherein is contained a Method of Calculating all Numbers for Watches. Written originally by that famous Mathematician Mr. William Oughtred, and now made Publick. By J. S. of London, Clock-maker. London, 1675. “J. S.” says in his preface: The method following was many years since Compiled by Mr. Oughtred for the use of some Ingenious Gentlemen his friends, who for recreation at the University, studied to find out the reason and Knowledge of Watch-work, which seemed also to be a thing with which Mr. Oughtred himself was much affected, as may in part appear by his putting out of his own Son to the same Trade, for whose use (as I am informed) he did compile a larger tract, but what became of it cannot be known. Notwithstanding Oughtred’s marked activity in the design of mathematical instruments, and his use of surveying instruments, he always spoke in deprecating terms of their importance and their educational value. In his epistle against Delamain he says: