GUN
653 GUN
extremes of which may be marked with black lines on the ribbon,and the word proof written in the middle-line betwixt the two.But it the experiments are made with sufficient accuracy, therewill commonly be very little difference in the length to which theribbon is drawn out. Thus- the comparative goodness of powdermay easily be ascertained ; for the stronger the powder is, thegreater will be the recoil, and consequently the greater length towhich the ribbon will be drawn out: and if care is taken in pro-portioning the charge to the weight of the bullet, to come as nearas possible to the medium proportion that obtains in practice, thedetermination of the goodness of gunpowder from the result of thisexperiment cannot fail to hold good in actual service. That which isfound to answer best is a small cannon, the bore of which is aboutone inch in diameter, and it is usually charged with two ounces ofpowder, and with powder only, as a ball is not necessary, and thestrength of the powder Is accurately shown by the arc of the gun’srecoil.
Gunpowder, Statutes Respecting. No person shall makegunpowder, but in the regular manufactories established at the timevA making the statute 12 George III . c. 61, or licensed by the ses-sions, pursuant to certain provisions, under forfeiture of the gun-powder, and two shillings per pound ; nor are pestle-mills to beused under a similar penalty. Only forty pounds of powder is tobe made at one time under one pair of stones, except Battle-pow-der. made at Battle and elsewhere in Sussex. Not more than fortyhundred weight to be dried at one time in one stove; and thequantity only required for immediate use to be kept in or near theplace of making, except in brick or stone magazines, fifty yards atleast from the mill. Not more than twenty-live barrels to be car-ried in any land-carriage, nor more than two hundred barrels bywater, unless going by sea or coastwise, each barrel not to containmore than one hundred pounds. No dealer to keep more thantwo hundred pounds of powder, nor any person not a dealer, morethan fifty pound in the cities of London and Westminster, or with-in 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 for-feiture, and two shillings per pound, except in licensed mills, or tothe amount of three hundred pounds for the use of collieries, withintwo hundred yards of them.
GUNTER, Edmund, M. A. and B. D. an excellent mathema-tician, born in Hertfordshire in 1581. He studied at Westminsterand Oxford, where he graduated in 160G, and 1615. Being emi-nent for his knowledge in the mathematics, he was in 1613, chosenprofessor of astronomy in Gresham-collcge, where he distinguishedhimself by his lectures and writings, lie improved the trigono-metrical tables then in use, by adapting them to the solution ofspherical triangles without the aid of secants. In 1622 he madethe important discovery that the variation of the needle varies.Soon after he invented the rule for working questions in proportioninstrumentallv, which is an easy and excellent method of combin-ing arithmetic and geometry, adapted to the understanding of per-sons of the most ordinary capacities. The lines on which theoperation is performed, is called Gunter’s line. He also inventeda quadrant, and greatly improved the sector and other instruments.We are indebted to him for many other inventions and improvements,most of which are printed in his works. He died at Gresham-col-lege in 1626. His first publication was entitled “ Canon Trian-gulorum.” IIis works have been collected, and various editionsof them have been published. The fifth is by William Leybourn ,in 1673, 4lh., containing the description and use of the sector,cross-stalf, bow, quadrant, and other instruments; with severalpieces added by Samuel Eoster, llenry Bond, and William Ley-bourn.
Gunter’s Chain, the chain in common use for measuring land,according to true or statute measure; so called from Mr. Gunter,its reputed inventor. The length of the chain is 66 fce|, or 22vards, or four poles, of 5-j yards each; and it is divided into 100links, of 7,92 inches each. This chain is the most convenient ofany thing for measuring land, because the contents thence com-puted are so easily turned into acres. 1 he reason of which is,that an acre of land is just equal to 10 square chains, or 10 chainsin length and one in breadth, or equal to 100,000 square links.Hence, the dimensions being taken m chains, and multiplied to-gether, it gives the content in square chains, which therefore being
divided lay 10, or a figure cut off for decimals, brings the contentto acres; after which the decimals are reduced to roods and per-ches, by multiplying by 4 and 40. But a better way is to setthe dimensions down in links, as integers, considering each chainas 100 links; then, having found the content in square links, dividethese by 100,000, that is, cut off five places for decimals, the restare acres, and the decimals are reduced to roods and per-ches as before. Suppose a rectangular field to be measured be624 links in length, and 550 in breadth, to find its area we say
624
550
31200
3120
3. '132034
1.72800
40
29.12 •
The area, or quantity of surface, is 3 A. I R. 29P.
Gunter’s Line, a logarithmic line, usually graduated uponscales, sectors, &c. It is also called the line of lines, and line ofnumbers; being only the logarithms graduated upon a ruler, whichtherefore serves to solve problems instrumentally in the same man-ner as logarithms do arithmetically. It is usually divided into anhundred parts,every tenth whereo’f is numbered, beginning with 1,and ending with 10 ; so that if the first great division, marked 1,stand for one-tenth of any integer, the next division, marked 2,will stand for two-tenths; 3, tliree-tentljs, and so on ; and the in-termediate divisions will, in like manner, represent 100th parts ofthe same integer. R each of the great divisions represent 10 in-tegers, then will the less divisions stand for integers; and if thegreat divisions be supposed each 100, the subdivisions will beeach 10
Gunter’s Line, Use of. 1. To find the product of two num-bers. From 1. extend the compasses to the multiplier; and thesame extent, applied the same way from the multiplicand, willreach to the product, 'flius, if the product of 4 and 8 be required,extend the compasses from 1' to 4, and that extent laid from 8 thesame way, will reach to 32, their product. 2. To divide one num-by another. The extent from the divisor to unity will reach fromthe dividend to the quotient: thus to divide 36 by 4, extend (hecompasses from 4 to 1, and the same extent will reach from 36 to9, the quotient sought. 3. To three given numbers, to find a4th proportional. -Suppose the numbers 6, S, 9; extend the com-passes from 6 to 8, and this extent, laid from 9 the same way, willreach to 12, the fourth proportional required. 4. To find a meanproportional between any two given numbers. Suppose 8 and 32:extend the compasses from 8 in the left hand part of the line to 32in the right; then bisecting this distance, its half will reach from 8forward, or from 32 backward, to 16, the mean proportional sought.5. To extract the square root of any number. Suppose 25: bi-sect the distance between one on the scale and the point represent-ing 25; then the half of this distance, setoff from 1, will give thepoint represecting the root 5. In the same manner the cube root, orthat of any higher power, may be found by dividing the distanceon the line, between 1 and the given number, into as many equalparts as the index of the power expresses; then one of those parts,set from l, will find the point representing tiie root required.
Gunter’s Quadrant, one made of wood, brass, &c. contain-ing a kind of stereographic projection of the sphere, on the planeof the equinoctial; the eye being supposed placed in one of thepoles. See Quadrant. f
Gunter’s Scale, usually called by seamen the Gunter, is alarge plain' scale, having various lines upon it, of great use in work-ing the cases or questions in navigation. This scale is usually twofeet long, and about an inch and a half broad, with various linesupon it, both natural and logarithmic, relating to trigonometry,navigation, Sec. On the one side are the natural lines, and on theother the artificial or logarithmic ones. The former side is firstdivided into indies and tenths, and numbered from one to twenty8 D tour