Edward Wright (baptised 8 October 1561; died November 1615) was an English mathematician and cartographer noted for his book Certaine Errors in Navigation (1599; 2nd ed., 1610), which for the first time explained the mathematical basis of the Mercator projection by building on the works of Pedro Nunes, and set out a reference table giving the linear scale multiplication factor as a function of latitude, calculated for each minute of arc up to a latitude of 75°. This was in fact a table of values of the integral of the secant function, and was the essential step needed to make practical both the making and the navigational use of Mercator charts.
Wright was born at Garveston in Norfolk and educated at Gonville and Caius College, Cambridge, where he became a fellow from 1587 to 1596. In 1589 the college granted him leave after Elizabeth I requested that he carry out navigational studies with a raiding expedition organised by the Earl of Cumberland to the Azores to capture Spanish galleons. The expedition's route was the subject of the first map to be prepared according to Wright's projection, which was published in Certaine Errors in 1599. The same year, Wright created and published the first world map produced in England and the first to use the Mercator projection since Gerardus Mercator's original 1569 map.
Not long after 1600 Wright was appointed as surveyor to the New River project, which successfully directed the course of a new man-made channel to bring clean water from Ware, Hertfordshire, to Islington, London. Around this time, Wright also lectured mathematics to merchant seamen, and from 1608 or 1609 was mathematics tutor to the son of James I, the heir apparent Henry Frederick, Prince of Wales, until the latter's very early death at the age of 18 in 1612. A skilled designer of mathematical instruments, Wright made models of an astrolabe and a pantograph, and a type of armillary sphere for Prince Henry. In the 1610 edition of Certaine Errors he described inventions such as the "sea-ring" that enabled mariners to determine the magnetic variation of the compass, the sun's altitude and the time of day in any place if the latitude was known; and a device for finding latitude when one was not on the meridian using the height of the pole star.
Apart from a number of other books and pamphlets, Wright translated John Napier's pioneering 1614 work which introduced the idea of logarithms from Latin into English. This was published after Wright's death as A Description of the Admirable Table of Logarithmes (1616). Wright's work influenced, among other persons, Dutch astronomer and mathematician Willebrord Snellius; Adriaan Metius, the geometer and astronomer from Holland; and the English mathematician Richard Norwood, who calculated the length of a degree on a great circle of the earth using a method proposed by Wright.
Family and education The younger son of Henry and Margaret Wright, Edward Wright was born in the village of Garveston in Norfolk, East Anglia, and was baptised there on 8 October 1561. It is possible that he followed in the footsteps of his elder brother Thomas (died 1579) and went to school in Hardingham.Parsons & Morris, p. 61. The family was of modest means, and he matriculated at Gonville and Caius College, University of Cambridge, on 8 December 1576 as a sizar.. Sizars were students of limited means who were charged lower fees and obtained free food and/or lodging and other assistance during their period of study, often in exchange for performing work at their colleges.
Wright was conferred a Bachelor of Arts (B.A.) in 1580–1581. He remained a scholar at Caius, receiving his Master of Arts (M.A.) there in 1584, and holding a fellowship between 1587 and 1596. At Cambridge, he was a close friend of Robert Devereux, later the Second Earl of Essex, and met him to discuss his studies even in the weeks before Devereux's rebellion against Elizabeth I in 1600–1601. In addition, he came to know the mathematician Henry Briggs; and the soldier and astrologer Christopher Heydon, who was also Devereux's friend. Heydon later made astronomical observations with instruments Wright made for him.
Foreign expedition
In 1589, two years after being appointed to his fellowship, Wright was requested by Elizabeth I to carry out navigational studies with a raiding expedition organised by the Earl of Cumberland to the Azores to capture Spanish galleons. The Queen effectively ordered Caius to grant him leave of absence for this purpose, although the college expressed this more diplomatically by granting him a sabbatical "by Royal mandate". Wright participated in the confiscation of "lawful" prizes from the French, Portuguese and Spanish – Derek Ingram, a life fellow of Caius, has called him "the only Fellow of Caius ever to be granted sabbatical leave in order to engage in piracy". Wright sailed with Cumberland in the Victory from Plymouth on 8 June 1589; they returned to Falmouth on 27 December of the same year. An account of the expedition is appended to Wright's work Certaine Errors of Navigation (1599), and while it refers to Wright in the third person it is believed to have been written by him.
In Wright's account of the Azores expedition, he listed as one of the expedition's members a "Captaine Edwarde Carelesse, alias Wright, who in S. Frauncis Drakes West-Indian voiage was Captaine of the Hope". In another work, The Haven-finding Art (1599) (see below), Wright stated that "the time of my first employment at sea" was "now more than tenne yeares since". The Oxford Dictionary of National Biography asserts that during the expedition Wright called himself "Captain Edward Carelesse", and that he was also the captain of the Hope in Sir Francis Drake's voyage of 1585–1586 to the West Indies, which evacuated Sir Walter Raleigh's Colony of Virginia. One of the colonists was the mathematician Thomas Harriot, and if the Dictionary is correct it is probable that on the return journey to England Wright and Harriot became acquainted and discussed navigational mathematics. However, in a 1939 article, E.J.S. Parsons and W.F. Morris note that in Capt. Walter Bigges and Lt. Crofts' book A Summarie and True Discourse of Sir Frances Drakes West Indian Voyage (1589),. Edward Careless was referred to as the commander of the Hope, but Wright was not mentioned. Further, while Wright spoke several times of his participation in the Azores expedition, he never alluded to any other voyage. Although the reference to his "first employment" in The Haven-finding Art suggests an earlier venture, there is no evidence that he went to the West Indies. Gonville and Caius College holds no records showing that Wright was granted leave before 1589. There is nothing to suggest that Wright ever went to sea again after his expedition with the Earl of Cumberland.
Wright resumed his Cambridge fellowship upon returning from the Azores in 1589, but it appears that he soon moved to London for he was there with Christopher Heydon making observations of the sun between 1594 and 1597, and on 8 August 1595 Wright married Ursula Warren (died 1625), a daughter of Augustine Bernher, at the parish church of St. Michael, Cornhill, in the City of London.Parish register, London, St. Michael Cornhill, 8 August 1595, GL [marriage]: see Apt, "Wright, Edward", Oxford Dictionary of National Biography. They had a son, Samuel (1596–1616), who was himself admitted as a sizar at Caius on 7 July 1612.Parsons & Morris, p. 71. The St. Michael parish register also contains references to other children of Wright, all of whom died before 1617. Wright resigned his fellowship in 1596.
Mathematician and cartographer Certaine Errors in Navigation
Wright helped the mathematician and globe maker Emery Molyneux to plot coastlines on his terrestrial globe, and translated some of the explanatory legends into Latin. Molyneux's terrestrial and celestial globes, the first to be manufactured in England, were published in late 1592 or early 1593, and Wright explained their use in his 1599 work Certaine Errors in Navigation. He dedicated the book to Cumberland, to whom he had presented a manuscript of the work in 1592,Lewi, "Mercator, Wright and Mapmaking", pp. 24–25. stating in the preface it was through Cumberland that he "was first moved, and received maintenance to divert my mathematical studies, from a theorical speculation in the Universitie, to the practical demonstration of the use of Navigation".
The navigation errors addressed by Wright in Certaine Errors in Navigation had been previously treated by Pedro Nunes, whose works had been compiled in Petri Nonii Salaciensis Opera in 1566 (later expanded, corrected and re-edited as De arte adque ratione navigandi in 1573). This is pointed out by Wright himself in the Preface:
This appeal to the authority of Pedro Nunes and the fact that the first chapter treats the Faults in the common Sea Chart, With Rumbes expressed by right lines and degrees of latitude, everywhere equal, show Nunes' influence in Wright's work. In addition, the effect of following a rhumb line course on the surface of a globe was first discussed by Pedro Nunes in 1537 in his Treatise in Defense of the Marine Chart. In this work, Nunes proposes the construction of a nautical atlas composed of several large-scale sheets in the cylindrical equidistant projection as a way to minimize distortion of directions. If these sheets were brought to the same scale and assembled, they would approximate the Mercator projection, later introduced by Gerardus Mercator in 1569. Mercator never explained the method of construction of the projection bearing his name, nor how he arrived at it. Various hypotheses have been tendered over the years, but in any case Mercator's friendship with Pedro Nunes and his access to the loxodromic tables Nunes created likely aided his efforts. Mercator's projection was advantageous for nautical purposes as it represented lines of constant true bearing or true course (rhumb lines), as straight lines.
In Certaine errors of navigation, Wright improved and diversified Nunes' charting method, thus explaining the construction and use of the Mercator projection. As Wright himself puts it in Chapter 2:
In order to achieve this, Wright introduces the method for dividing the meridian, an explanation of how he had constructed a table for the division, and the uses of this information for navigation. On a globe, circles of latitude (also known as parallels) get smaller as they move away from the Equator towards the North or South Pole. Thus, in the Mercator projection, when a globe is "unwrapped" on to a rectangular map, the parallels need to be stretched to the length of the Equator. In addition, parallels are further apart as they approach the poles. Wright compiled a table with three columns. The first two columns contained the degrees and minutes of latitudes for parallels spaced 10 minutes apart on a sphere, while the third column had the parallel's projected distance from the Equator. Any cartographer or navigator could therefore lay out a Mercator grid for himself by consulting the table.Monmonier, Rhumb Lines and Map Wars, pp. 63–64. Wright explained: