. A treatise on surveying and navigation: uniting the theoretical, the practical, and the educational features of these subjects. al to 23 fromthe same scale of equal partsthat AD was taken from. ThenE will be the place of the ship,at the end of the second course. Make Sc=5± points, Nd 7£points, and Se 5J points, taken from the line of chords. ThroughE draw EF, parallel to Ac, and make it equal to 36, from the scaleof equal parts ; through F draw FG parallel to Ad, and make itequal to 12, from the scale of equal parts ; through G draw GBparallel to Ae, and make it equal to 21, from the scale o
. A treatise on surveying and navigation: uniting the theoretical, the practical, and the educational features of these subjects. al to 23 fromthe same scale of equal partsthat AD was taken from. ThenE will be the place of the ship,at the end of the second course. Make Sc=5± points, Nd 7£points, and Se 5J points, taken from the line of chords. ThroughE draw EF, parallel to Ac, and make it equal to 36, from the scaleof equal parts ; through F draw FG parallel to Ad, and make itequal to 12, from the scale of equal parts ; through G draw GBparallel to Ae, and make it equal to 21, from the scale of equalparts. Demit B C a perpendicular, on the meridian NC, and joinAB ; then B will be the place of the ship, AB her distance fromthe place which she left, A Cher difference of latitude, BC her de-parture, and BA C the course which she has made on the , AB, AC, and BC being measured on the scale of equal partsfrom which the distances were taken, we have AB=, AC=, and .6(7= miles. And the arc included by A C and BC,if measured on the line of chords, gives about 18° for the measureof the course BA * Two and | points is 25° 18 45, that is, take the chord of 25° 18 in thedividers, and set it off from s to a, and so on, for other angles. TRAVERSE SAILING. TRAVERS E TABLE. 189 Courses. Points. Dis. Diff. Lat. Dep. ~H 16 N. s. E. w. SL ±E. E. S. E. 6 23 S. IF. by w.\w. 54- 36 W.\N. 7i 12 IE. H 41 Result I Lat. leftdiff. lat. - Lat. in 51° 25 00 S. 50 25 K Mid. lat. 50° 55To find the course and distance, by trigonometry, As dif. lat. miles : radius 90°: : dep. miles : tan. course 18° 12 As sin. course 18° 12: dep. miles: Radius : Dis. milesTo find the dif. of cos. 50° 55 : Radius: : dep. : diff. Ion. miles Longitude leftdiff. in 1,775246 1
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Keywords: ., boo, bookcentury1800, booksubjectnavigation, booksubjectsurveying
