GUN 
GUN'STONE, /. The (hot of cannon. They ufed 
formerly to (hoot (tones from artillery : 
Tell the pleafant prince, this^mock of his 
Hath turn’d his ball to gunjlones,.a.n& his foul 
Shall (tand fore charged for the waffeful vengeance 
That (hall fly with them. - Shakefpeare. 
SUN'TER (Edmund), an eminent mathematician, 
born in the county of Hereford; in 1581. He received 
his claflical education on the royal foundation at Weft- 
minfter-fchool, whence he was eledted to Chrift-c-hurch 
college in Oxford. He was admitted to the degree of 
B. A. in 1603, and to that of M. A. in 160 6 ; after which 
he entered into orders, and proceeded bachelor of divi¬ 
nity in 1615. His genius had early led him to the pur- 
fuit of mathematical (tudies; and at the time when he 
toolc, his degree of M. A. he had merited the title of an 
inventor, by his new projection of the, fedtor, of which 
he then wrote a defcription in Latin, and permitted his 
friends to tranfcribe it, though the Englifh account of 
liis- invention was not publiflied till feveral years after¬ 
wards. The reputation which he.bad now acquired in 
the mathematical world occafioned his introdudtion to 
the acquaintance of fome of the ableff mathematicians of 
his,time, by whbfe recommendation and inhered he was 
eledted profeflor of aftronomy at Grefham college, Lon¬ 
don, in 1619. In this (ituation he foon diftinguiflied 
liimfclf by his lectures and by his writings, which con¬ 
tributed greatly to the improvement of fcience. His 
firft publication after his eledtion, appeared in 1620, and 
was entitled, Canon Triangulorumffve Tabula Sinuum artifi- 
cialium ad Radium 10,0000000, et ad Scrupvla prima Qua - 
drantis, 8vo. This treatife was accompanied with the 
fird 1000 of Briggs’s logarithms of common numbers. 
In the fecond edition of it, w hich was publidied in Erig- 
li(h in 1624, under the title of Canon Triangulorum, or 
Table of artificial Sines and Tangents to a Radius of 
10,0000000 Parts to each Minute of-the Quadrant, 4to. 
the logarithms were continued from 1000 to 10,000, and 
a rule was given at the end for augmenting them to 
joo.ooo. Thefe tables were the fird of the kind which 
had been given to the world, and, if the author had 
publidied nothing elfe, would have preferved his me¬ 
mory to the lated poderity, by the admirable aid which 
they afforded to dudents in aftronomy. 
In 1622, Mr. Gunter made his important difcovery, 
that the variation of the magnetic needle itfelf varies. 
To this difcovery he was led in the courfe of experi¬ 
ments which he made on the variation at Deptford, by 
which he found that the declination of the needle had 
changed almod five degrees in the fpace of forty-two 
years. . The truth of his difcovefy was afterwards con¬ 
firmed and edablilhed by Mr. Gellibrand, his fiicceflor 
at Grefham college. Soon after this he invented his fa¬ 
mous “ rule of proportion,” which is an eafy and excel¬ 
lent method, of combining arithmetic and geometry, 
adapted to the underdanding of perfons of the mod or¬ 
dinary capacities. It confids in-applying the loga¬ 
rithms of numbers, and of fines and tangents, to draight 
lines, drawn on a fcale or rule; by which proportions 
in common numbers and trigonometry may be refolved 
by the mere application of a pair of compades : a me¬ 
thod founded on this property, that the logarithms of 
the terms of equal radios are equi-different. This was 
called Gunter’s proportion, and Gunter’s line ; and the 
indrument, in the form of a two-foot fcale, is now in 
common ufe for navigation and other purpofes, and is 
commonly called the Gunter. In 1624, this invention 
was carried into France by Mr. Wingate, who not, only 
communicated it to mod of the principal mathemati¬ 
cians then at, Paris, but alfo, at their requed, publidied 
an account of its ufe in the French language. Mr. 
Gunter likewife greatly improved the feitor and other 
indruments, Tor the fame ufes, the defcription of all 
-which he publiflied in 1624, in a treatife, entitled, The. 
GUN 
Crofs-Staff, in three Books, &c. 4to. In the fame year 
he publidied, by king James’s order, a fmall tradt enti¬ 
tled, The Defcription and Ufe of his Majedy’s Dials in 
Whitehall Garden, 4to. Mr. Gunter was the fir (I who 
ufed the word cofine , for the fine of the complement of 
an arc. To him, likewife, the, mathematical world is 
indebted for many other inventions and improvements, 
mod of which were the fubjedts of his ledhires at Gre- 
(ham college, and afterwards difpofed into treatifes, 
which were printed in his works. The highed expec¬ 
tations were formed of his future fervices in the caufe 
of ufeful fcience, when they were unhappily difappoint- 
ed by his death in 1626, in the forty-fifth year of his 
age. His works have been carefully collected, and 
many editions of them publifhed. The fifth is by Wil¬ 
liam Leybourp, in 1673, 4to. containing the defcription 
and ufe of the fector, crofs-daff, bow, quadrant, and 
other indruments ; with feveral pieces added by Samuel 
Forfter, Henry Bond, and William Leybourn, 
GUN'TER’s CHAIN, the chain now in common ufe 
for meafuriffg land, -according to flatute meafure; fo 
called from Mr. Gunter, its inventor. The length of 
the chain is fixty-fix‘feet, or twenty-two yards, or four 
poles of five and a half yards each ; and it is divided 
into one hundred links, of 7-92 inches,each. This 
chain is the mod convenient of all inventions for mea- 
•furing land, becaufe the contents thence computed are 
fo eafily turned into acres. The reafon of which is, 
that an acre of land is jud equal to ten fquare chains, 
or ten chains in length and one in breadth, or equal to 
100,000 fquare links. Hence,* the dimenfions being taken 
in chains, and multiplied together, it gfves the content 
in fquare chains; which therefore being divided by 10, 
or a figure cut off for decimals, brings the content to 
acres ;' after which- the decimals are reduced to roods 
and perches, by multiplying by 4 and 40. But the bet¬ 
ter way is to fet the dimenfions down in links as in¬ 
tegers, confidering each chain as 100 links; then, hav- 
ing'multiplied the dimenfions together, producing fquare 
links, divide thel'e by 100,000, that is, cut off five places 
for decimals, the red are acres, and the decimals are re¬ 
duced to roods and perches, as before. 
Example. Suppofe in meafuring a reftangular 
piece of ground, its length be 795 links, 
and its breadth 480 links. 
63600 
3'8o 
Ac. 3-81600 
Ro. 3-264 
_ 40 _ 
Per. 10-560 
So the content is 3 acres, 3 roods, 10 perches. 
GUN'TER’s LINE, a logarithmic line, ufually gra¬ 
duated upon fcales, feftors, &c. and fo called from its 
inventor Mr. Gunter. This is otherwife called the line 
of lines, or line of numbers, and confids of the logarithms 
transferred upon a rule, from the tables, by means of a 
fcale of equal parts, which therefore ferves to refolve 
problems indrumentally, in the fame manner as loga¬ 
rithms do arithmetically. For, whereas logarithms re- 
folve proportions, or perform multiplication and divi- 
fion, by only addition.and fubtrablion, the fame are.per-, 
formed on this line, by turning a pair of compafles over 
this way or that, or by Aiding one flip of wood by the 
fide of another, &c. This line has been contrived va¬ 
rious ways, for the advantage of Jiaving it as long as 
poilible. As, fird, on the two-feet rule or fcale, by 
Gunter. Then, in 1627, the logarithms were drawn by 
Wingate on two feparate rulers, Aiding againft each 
other, to fave the ufe of pompafles in refolving propor¬ 
tions. Tfley were alfo in 1627 applied to concentric 
circles by Oughtred, Then in a fpiral fop by Mr. 
.Miibv\r.ce 
