. Mathematics, compiled from the best authors and intended to be the text-book of the course of private lectures on these sciences in the University at Cambridge [microform]. SPHERIC ASTRONOMY. 499 therefore they may be considered as respectively ZVV, or ZW, may be considered as the differenceof die zenith distances ; ihe former increasing the distance,and the latter decreasing it. To find this difference,observethe angle VZT, or VZT, formed by the rhumb line, onwhich the ship sails, and the suns bearing. 1 hen, in theright-angled plane triangles VZW, VZW, the data are theangles, a
. Mathematics, compiled from the best authors and intended to be the text-book of the course of private lectures on these sciences in the University at Cambridge [microform]. SPHERIC ASTRONOMY. 499 therefore they may be considered as respectively ZVV, or ZW, may be considered as the differenceof die zenith distances ; ihe former increasing the distance,and the latter decreasing it. To find this difference,observethe angle VZT, or VZT, formed by the rhumb line, onwhich the ship sails, and the suns bearing. 1 hen, in theright-angled plane triangles VZW, VZW, the data are theangles, and the side ZV, or ZV, the distance or lengdi ofthe run; to find ZW, or Z W. Example. Given the suns declination 14° 30 N, itstrue altitude 47° 30 by the former oi two obseivations, bothtaken in the forenoon, and *6° 30 by the latter ; the intervalof time being ih. 44 ; required the latitude oi uie = PT = 75° 30= = 42° 30 - ast co-ait. ZT= 33 30 ==2Ucp-a*t. ZSPT = 26 == interval ui time. Draw the perpendic-ulars Pr and ZN, inthe triangles PbT andand PZS. PoT beingan isosceles triangle, Prbisects the angle SPT,and the side Cot. £ZSPT 13°: R 90:: Cos. PS 75 30 ar. co. 9*363364110* 9*3985996 : Cot. ZPST 86 41 30 8*7619637 R 90°: Sin. PS 75 30::Sin.|ZSPTi3 10* 9*98 5941693 *20880 : Sin. Sr. 12 34 44 2 9*3380296 ST 25 92 8 500 MATHEMATICS ZS = 42°ZT=33ST = 25 30 30 9 28 . sine sine sinesine 16 43 sine2 2) 2)101 50ZS 42 9 3430 28 44 8 4 44 1st. rem 9-1477889 50ST 25 349 4428 25 ZS42°ST 25 25 309 16 2d rem. co-arc28 co-arc \ ZZST 27° 9*6327285 1932233u39 6611651 ZST 54 3j 26 PST 86° 41 SOZST 54 33 26 PSZ 32 8 4 Cot. ZS:R :: Cos. ZSn 42° 30 90 32 8 4 ar. 90. SP : Tang. Sn 37 48 35 Sn=Pn = 37°4l25. 9*96205251099277820 98898345 Cos. Sn 37° 48 35 ar. co. 0*1023449 : Cos. SZ 42 30 9*8676309 ::Cos. Pn 37 41 25 9*8983561 : Cos. PZ* 42 23 56 9*8683319 * R : cos. nZ : : cos. Sn : cos. SZ > By the Catholic Pro- R : cos. nZ :: cos. Pn :
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