Gunter, Edmund

, an English mathematician, was of Welsh extraction, from a family at Gunter’s-town, in Brecknockshire but his father being settled in the county of Hereford, had this son born to him there in 1581. As he was a gentleman possessed of a handsome fortune, he thought proper to give him a liberal education, to which end he was placed by Dr. Busby at Westminster-school, where he was admitted a scholar on the foundation, and elected student of Christ-church, Oxford, in 1599. Having | taken both his degrees in arts at the regular times, he entered into orders, and became a preacher in 1614, and proceeded B. D. November 23, 1615. But genius and inclination leading him chiefly to mathematics, he applied early to that study; and about 1606, merited the title of an inventor by the new projection of his sector, which he then described, together with its use, in a Latin treatise; and several of the instruments were actually made according to his directions. These being greatly approved, as being more extensively useful than any that had appeared before, on account of the greater number of lines upon them, and those better contrived, spread our author’s fame universally their uses also were more largely and clearly shewn than had been done by others and though he did not print them, yet many copies being transcribed and dispersed abroad, carried his reputation along with them, recommended him to the patronage of the earl of Bridgewater, brought him into the acquaintance of the celebrated Mr. Oughtred, and Mr. Henry Briggs, professor of geometry at Gresham; and thus, his fame daily increasing the more he became known, he was preferred to the astronomy-chair at Gresham-college, on March 6, 1619.

He had invented a small portable quadrant, for the more easy finding of the hour and azimuth, and other solar conclusions of more frequent use, in 1618; and in 1620, he published his Latin “Canon Triangulorum, or Table of artificial Sines and Tangents to the Radius 10,000,000 parts, to each Minute of the Quadrant.” This was a great improvement to astronomy, by facilitating the practical part of that science in the resolution of spherical triangles without the use of secants or versed sines, the same thing being done here (by addition and subtraction only) for performing which the former tables of right sines and tangents required multiplication and division. This admirable help to the studious in astronomy was gratefully commemorated, and highly commended, by several of the most eminent mathematicians who were his contemporaries, and who at the same time did justice to his claim to the improvement, beyond all contradiction.

The use of astronomy in navigation unavoidably draws the astronomer’s thoughts upon that important subject; and accordingly we find Gunter discovering a new variation in the magnetic needle, or the mariner’s compass, in 1 Gilbert, in the beginning of that century, had | incontestibly established the first discovery of the simple variation; after which the whole attention of the studious in these matters was employed in settling the rule observed by nature therein, without the least apprehension or suspicion of any other; when our author, making an experiment at Deptford in the above year, found that the direction of the magnetism there had moved no less than five degrees within two minutes, in the space of forty-two years. The fact, however, was so surprising, and so contrary to the opinion then universally received of a simple variation only, which had satisfied and bounded all their curiosity, that our author dropt the matter apparently, expecting, through modesty, an error in his observation to have escaped his notice in his experiment. But afterwards, what he had done induced his successor at Gresham, Mr. Gellibrand, to pursue it; and, the truth of Gunter’s experiment being confirmed by a second, farther inquiry was made, which ended in establishing the fact. We have since seen Halley immortalize his name, by settling the rule of it in the beginning of the last century.

The truth is, Gu-nter’s inclination was turned wholly the same way with his genius; and it cannot be denied that he reached the temple of fame by treading in that road. To excite a spirit of industry in prosecuting mathematical knowledge, by lessening the difficulties to the learner; to throw new light into some things, which before appeared so dark and abstruse as to discourage people of ordinary capacities from attempting them; and by that means to render things of wonderful utility in the ordinary employment of life so easy and practicable as to be managed by the common sort; is the peculiar praise of our author, who effected this by that admirable contrivance of his famous rule of proportion, now called the line of numbers, and the other lines laid down by it, and fitted in his scale, which, after the inventor, is called “Gunter’s scale;” the description and use of which he published in 1624, 4to, together with that of his sector and quadrant already mentioned. His fame having reached the ears of his sovereign, prince Charles gave directions, that he should draw the lines upon the dials in Whitehall garden, which were destroyed in Charles Il.'s time, and give a description and use of them; and king James ordered him to print the book the same year, 1624. There was, it seems, a square sj;one there before of the same si?e and form, having five | dials upon the upper part, one upon each of the four corners, and one in the middle, which was the principal dial, being a large horizontal concave; besides these, there were others on the sides, east, west, north, and south; but the lines on our author’s dial, except those which shewed the hour of the day, were greatly different. And Dr. Wallis tells us, that one of these was a meridian, in fixing of which great care was taken, a large magnetic needle being placed upon it, shewing its variation irom that meridian from time to time. If the needle was placed there with that intention by our author, it is a proof that his experiment at Deptford had made so much impression upon him, that he thought it worth while to pursue the discovery of the change in the variation, of which the world would doubtless have reaped the fruits, had his life been continued long enough for it. Unfortunately, however, for science, he died December 10, 1G26, about his forty-fifth year, and in the prim of life, at Gresham college, and was buried in St. Peter the Poor, Broad-street, without any monument or inscription; hut his memory will always be preserved in the mathematical world as an inventor, and the parent of instrumental arithmetic. The 5th edition of his works was published by Mr. Leybourn in 1674, 4to. 1


Biog. Brit. —Hutton’s Dictionary, and Cydopredia, in articles Sector, Scale, &c. Ward’s Greshaw Professors, —Ath. Ox, vol. I.