GUNTER. 



in the cities of London and Westminster, 

 or within three miles thereof, or within 

 any other city, borough, or market-town, 

 or one mile thereof, or within two miles 

 of the king's palaces or magazines, or 

 half a mile of any parish church, on pain 

 of forfeiture, and two shillings per pound, 

 except in licensed mills, or to the amount 

 of three hundred pounds for the use of 

 collieries, within two hundred yards of 

 them. 



GUNTER (EDMUND,) an English ma- 

 thematician of the seventeenth century, 

 was descended from a"n ancient atid re- 

 spectable family in Brecknocshire, South 

 Wales, and was born in the county of 

 Herefordshire in the year 1580. He re- 

 ceived his classical education on the royal 

 foundation at Westminster School,whence 

 he was elected at about eighteen years 

 of age to Christ Church College, in Ox- 

 ford. He was admitted to the degree of 

 B. A. in 1603, and to that of M. A. in 

 1606 ; after which he entered into orders, 

 and proceeded bachelor of divinity in the 

 year 1615. His genius had early led 

 him to the pursuit of mathematical stu- 

 dies; and at the time when he took his 

 degree of M. A. he had'merited the title 

 of an inventor by his new projection of 

 the sector, of which he then wrote a de- 

 scription in Latin, and permitted his 

 friends to transcribe it, though the Eng- 

 lish account of his invention was not pub- 

 lished till several years afterwards. In 

 the year 1618, he had invented a small 

 portable quadrant, for the more easy find- 

 ing the hour and azimuth, and more use- 

 ful astronomical purposes. The reputa- 

 tion which he had now acquired in the 

 mathematical world occasioned his intro- 

 duction to the acquaintance of some of 

 the most able mathematicians of his time, 

 by whose recommendation and interest 

 he was elected professor of astronomy at 

 Gresham College, London, in the year 



1619. In this situation he soon distin- 

 guished himself by his lectures and his 

 writings, which contributed greatly to 

 the improvement of science, and reflected 

 credit to the choice that had been made 

 of him to that professorship. His first 

 publication after his election appeared in 



1620, and was entitled "Canon Trian- 

 gulorum, sive Tabulae simmm artificiali. 

 um ad radium 10.0000000, etad Scrupula 

 prima Quadrantis," 8vo. This treatise 

 was accompanied with the first 1,000 of 

 Brigg's logarithms of common numbers. 

 In the second edition of it, which was 

 published in English in 1624, under the 

 title of " Canon Triangulorum, OP Table 



of artificial Sines and Tangents to a ra- 

 dius of 10.0000000 Parts to each Minute 

 of the Quadrant," 4to., the logarithms 

 were continued from 1,000 to 10,000, and 

 a rule was given at the end for augmenting 

 them to 100,000. These tables were the 

 first of the kind which had been given to 

 the world, and, if the author had publish- 

 ed nothing else, would have preserved his 

 memory to the latest posterity, by the ad- 

 mirable aid which they afforded to stu- 

 dents in astronomy; for they greatly faci- 

 litated the practical parts of that science, 

 by furnishing a method of solving speri- 

 cal triangles without the aid of secants or 

 versed sines : the same thing being ef- 

 fected by addition and subtraction only, 

 which in the use of the former tables of 

 right sines and tangents required multi- 

 plication and division. Due praise was 

 bestowed upon him by many of the most 

 eminent mathematicians among his con- 

 temporaries, for the service which he ren- 

 dered to science by this most excellent 

 work; and his right to the improvement of 

 logarithms, by their application to sphe- 

 rical triangles, was satisfactorily establish- 

 ed by Mr. Edmund Windgate, Mr. Robert 

 Burton, and Mr. Henry Bond, sen. 



In the year 1622, Mr. Gunter made 

 his important discovery, that the variation 

 of the magnetic needle varies. To this 

 discovery he was led in the course of 

 lectures he made on the variation at 

 Deptford, by which he found, that the de- 

 clination of the needle had changed al- 

 most five degrees in the space of forty- 

 two years. The truth of this discovery 

 was afterwards confirmed and established 

 by Mr. Gellibrand, his successor at Gre- 

 sham College. Soon after this he in- 

 vented his famous " rule of proportion," 

 which is an easy and excellent method 

 of combining arithmetic and geometry, 

 adapted to the understanding of persons 

 of the most ordinary capacities. It con- 

 sists in applying the logarithms of num- 

 bers and of sines and tangents to straight 

 lines drawn on a scale or rule, by which, 

 proportions in common numbers and tri- 

 gonometry may be resolved by the mere 

 application of a pair of compasses : a me- 

 thod founded on this property, that the lo- 

 garithms of the terms of equal ratios are 

 equidifferent. This was called Gunter's 

 proportion and Gunter's line ; and the in- 

 strument in the form of a two foot scale 

 is now in common use for navigation and 

 other purposes, is and commonly called 

 the Gunter. In the year 1624, this in- 

 vention was carried into France by Mr. 

 Wingate, who not only communicated it 



