# OUGHTRED (William)

, an eminent English mathematician and divine, was born at Eton in Buckinghamshire, 1573, and educated in the school there; whence he was elected to King's-college in Cambridge in 1592, where he continued about 12 years, and became a fellow; employing his time in close application to useful studies, particularly the mathematical sciences, which he contributed greatly, by his example and ex hortation, to bring into vogue among his acquaintances there.

About 1603 he quitted the university, and was presented to the rectory of Aldbury, near Guildford in Surry, where he lived a long retired and studious life, seldom travelling so far as London once a year; his recreation being a diversity of studies: “as often, says he, as I was tired with the labours of my own profession, I have allayed that tediousness by walking in the pleasant, and more than Elysian Fields of the diverse and various parts of human learning, and not of the mathematics only.” About the year 1628 he was appointed by the earl of Arundel tutor to his son lord William Howard, in the mathematics, and his Clavis was drawn up for the use of that young nobleman. He always kept up a correspondence by letters with some of the most eminent scholars of his time, upon mathematical subjects: the originals of which were preserved, and communicated to the Royal Society, by William Jones, Esq. The chief mathematicians of that age owed much of their skill to him; and his house was always full of young gentlemen who came from all parts to receive his instruction: nor was he without invitations to settle in France, Italy, and Holland. “He was as facetious, says Mr. David Lloyd, in Greek and Latin, as solid in arithmetic, geometry, and the sphere, of all measures, music, &c; exact in his style as in his judgment; handling his tube and other instruments at 80 as steadily as others did at 30; owing this, as he said, to temperance and exercise; principling his people with plain and solid truths, as he did the world with great and useful arts; advancing new inventions in all things but religion, which he endeavoured to promote in its primitive purity, maintaining that prudence, meekness, and simplicity were the great ornaments of his life.

Notwithstanding Oughtred's great merit, being a strong royalist, he was in danger, in 1646, of a sequestration by the committee for plundering ministers; several articles being deposed and sworn against him: but upon his day of hearing, William Lilly, the famous astrologer, applied to Sir Bulstrode Whitlocke and all his old friends; who appeared so numerous in his behalf, that though the chairman and many other Presbyterian members were active against him, yet he was cleared by the majority. This is told us by Lilly himself, in the History of his own Life, where he styles Oughtred the most famous mathematician then of Europe.—He died in 1660, at 86 years of age, and was buried at Aldbury. It is said he died of a sudden ecstasy of joy, about the beginning of May, on hearing the news of the vote at Westminster, which passed for the restoration of Charles the 2d.—He left one son, whom he put apprentice to a watch-maker, and wrote a book of instructions in that art for his use.

He published several works in his life time; the principal of which are the following:|

1. *Arithmeticæ in Numero & Speciebus Institutio,* in
8vo, 1631. This treatise he intended should serve as a
general Key to the Mathematics. It was afterwards
reprinted, with considerable alterations and additions,
in 1648, under the title of *A Key to the Mathematics.*
It was also published in English, with several additional
tracts; viz, one on the Resolution of all sorts of Affected
Equations in Numbers; a second on Compound
Interest; a third on the easy Art of Delineating all
manner of Plain Sun-dials; also a Demonstration of the
Rule of False-Position. A 3d edition of the same
work was printed in 1652, in Latin, with the same
additional tracts, together with some others, viz, On
the Use of Logarithms; A Declaration of the 10th
book of Euclid's Elements; a treatise of Regular Solids;
and the Theorems contained in the books of Archimedes.

2. *The Circles of Proportion,* and a *Horizontal Instrument;*
in 1633, 4to; published by his scholar Mr. William
Foster.

3. *Description and Use of the Double Horizontal Dial;*
1636, 8vo.

4. *Trigonometria:* his treatise on Trigonometry, in
Latin, in 4to, 1657: And another edition in English,
together with Tables of Sines, Tangents, and Secants.

He left behind him a great number of papers upon mathematical subjects; and in most of his Greek and Latin mathematical books, there were found notes in his own hand writing, with an abridgment of almost every proposition and demonstration in the margin, which came into the museum of the late William Jones Esq. F. R. S. These books and manuscripts then passed into the hands of his friend Sir Charles Scarborough the physician; the latter of which were carefully looked over, and all that were found fit for the press, printed at Oxford in 1676, in 8vo, under the title of

5. *Opuscula Mathematica hactenus inedita* This collection
contains the following pieces: (1), Institutiones
Mechanicæ: (2), De Variis Corporum Generibus Gravitate
& Magnitudine comparatis: (3), Automata:
(4), Quæstiones Diophanti Alexandrini, libri tres:
(5), De Triangulis Planis Rectangulis: (6), De Divisione
Superficierum: (7), Musicæ Elementa: (8) De
Propugnaculorum Munitionibus: (9), Sectiones Angulares.

6. In 1660, Sir Jonas Moore annexed to his Arithmetic
a treatise entitled, “*Conical Sections;* or, The
several Sections of a Cone; being an Analysis or Methodical
Contraction of the two first books of Mydorgius,
and whereby the nature of the Parabola, Hyperbola,
and Ellipsis, is very clearly laid down. Translated from
the papers of the learned William Oughtred.”

Oughtred, though undoubtedly a very great mathematician, was yet far from having the happiest method of treating the subjects he wrote upon. His style and manner were very concise, obscure, and dry; and his rules and precepts so involved in symbols and abbreviations, as rendered his mathematical writings very troublesome to read, and difficult to be understood. Beside the characters and abbreviations before made use of in Algebra, he introduced several others; as × to denote multiplication; : : for proportion or similitude of ratios; <*> for continued proportion; <*> <*> for greater and less; &c.