GUN 



GUS 



tend the compasses to the multiplier ; and 

 the same extent, applied the same way 

 from the multiplicand, will reach to the 

 product. Thus, if the product of 4 and 

 8 be required, extend the compasses 

 from 1 to 4, and that extent, laid from 8 

 the same way, will reach to 32, their pro- 

 duct. , 2. " To divide one number by 

 another." The extent from the divisor 

 to unity will reach from the dividend to 

 the quotient ; thus, to divide 36 by 4, ex- 

 tend the compasses from 4 to 1, and the 

 same extent will reach from 36 to 9, the 

 quotient sought. 3. * c To three given 

 numbers, to find a fourth proportional." 

 Suppose the numbers 6, 8, 9 ; extend the 

 compasses from 6 to 8, and this extent, 

 laid from 9 the same way, will reach to 

 12, the fourth proportional required. 4. 

 '* To find a mean proportional between 

 any two given numbers." Suppose 8 and 

 32 : extend the compasses from 8 in the 

 left-hand part of the line to 32 in the 

 right ; then bisecting this distance, its 

 half will reach from 8 forward, or from 

 32 backward, to 16, the mean propor- 

 tional sought. 5. " To extract the square 

 root of any number." Suppose 25: bisect 

 the distance between one on the scale 

 and the point representing 25 ; then the 

 half of this distance, set off' from 1, will 

 give the point representing the root 5. 

 In the same manner the cube root, or 

 that of any higher power, may be found, 

 by dividing the distance on the line, be- 

 tween 1 and the given number, into as 

 many equal parts as the index of the 

 power expresses ; then one of those parts, 

 set from 1, will find the point represent- 

 ing the root required. 



GUTTER'S quadrant, one made of wood, 

 brass, &c. containing a kind of stereo- 

 graphic projection of the sphere, on the 

 plane of the equinoctial; the eye being 

 supposed placed in one of the poles. Be- 

 sides the use of this quadrant in finding 

 heights and distances, it serves also to find 

 the hour of the day, the sun's azimuth, 

 and other problems of the globe. 



GUNTER'S scale, usually called by sea- 

 men the Gunter, is a large plain scale, 

 having various lines upon it, of great use 

 in working the cases or questions in na- 

 vigation. This scale is usually two feet 

 long, and about an inch and a half broad, 

 with various lines upon it, both natural 

 and logarithmic, relating to trigonometry, 

 navigation, &c. On the one side are the 

 natural lines, and on the other the artifi- 

 cial or logarithmic ones. The former 

 side is first divided into inches and tenths, 

 and numbered from one to twenty -four 



inches, running the whole length nea* 

 one edge. One half the length of this 

 side consists of two plain diagonal scales, 

 for taking off dimensions to three places 

 of figures. On the other half or foot of 

 this side are contained various lines re- 

 lating to trigonometry, in the natural 

 numbers, and marked thus, viz. 



Rumb, the rumbs or points of the com- 

 pass; 



Chord, the line of chords; 



Sine, the line of sines; 



Tang, the tangents ; 



S. T. The semi-tangents ; and at the 

 other end of this half are, 



Leag. leagues, or equal parts; 



Rumb, another line of rumbs ; 



M. L. miles of longitude ; 



Chor. another line of chords. 



Also in the middle of this foot are L, 

 and P, two other lines of equal parts : and 

 all these lines on this side of the scale 

 serve for drawing or laying down the 

 figures to the cases in trigonometry and 

 navigation. On the other side of the 

 scale are the following artificial or lo- 

 garithmic lines, which serve for working 

 or resolving those cases ; viz. 



S. R. the sine rumbs ; 



T. R. the tangent rumbs ; 



Numb, line of numbers ; 



Sine, sines; 



V. S. the versed sines; 



Tang, the tangents ; 



Meri. Meridional parts ; 



E. P. Equal parts. 



GUN-WALE, or gunnel, is the upper- 

 most wale of a ship, or that piece of tim- 

 ber which reaches on either side from the 

 quarter-deck to the forecastle, being the 

 uppermost bend which finishes the up- 

 per works of the hull, in that part in 

 which are put the stanchions which sup- 

 port the waste-trees. 



GUSSET, in heraldry, is formed by a 

 line drawn from the dexter or sinister 

 chief points, and falling down perpen- 

 dicularly to the extreme base. 



GUST, in sea-language, a sudden and 

 violent squall of wind, bursting from the 

 hills upon the sea, so as to endanger the 

 shipping near the shore. These are pe- 

 culiar to some coasts, as those of South 

 Barbary and Guinea. 



GUSTAVIA, in botany, so named in 

 memory of Gustavus 111. King of Sweden : 

 a genus of the Monadelphia Polyandria 

 class and order. Natural order of Myrti, 

 Jussieu. Essential character : calyx none; 

 petals several ; berry many-celled ; seeds 

 appendicled. There is but one species, 

 tiiz. G. augusta, which is a tree from 





