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2 I OTEMPORART FEMALE GENII’S. At no period of onr history has female genius trinmplietl jor.-fe than in ourovwi days. At the present time here are living not lest than twenty-four he.ics of pre-enuue&t tal ent, as writers iu various departments of literature and philosophy. Mrs. Barbauld, distinguished during 50 years by her elegant productions in verse and prose. Miss Hannah More, for nearly an equal period, for various moral and coutroversal writings; not inferior for style and energy of mind to any tiling produced by the other sex. Mrs. RadcJiffe, who, as a novelist, may be ranked among the tirsl geniuses of the age and country. Miss Edgeworth, a distinguished writer of novels, moral competition, and works ol education. Mbs Cullen, the amiable and ingenious authoress of Morton and Home, novels dis tinguished for their benevolent sentiments and spirited compositions, honorable alike to her heart and head. .Mrs. Opic, various works in verse and pn.se are distinguished for their originality, good taste, ingenuity, and elegant composi tion. Mrs. Inchbald, who, as a dramatist and novolist, has produced various works, which will ever rank high among the classics of our language. Miss Hutton, respectable as a novelist, powerful as a general writer, and able as a philosophical geographer, as proved by her recent works of Africa. M iss H. M. Wilhans, who, though long resident in Paris, may be claimed as an Eng b ,h women, and is an honor to the genius of her-country women, in history, politics, elo quence and poetry. Mrs. Cajipe, a lady whose strength of un derstanding and powers of diction have led her to grapple with subjects of the highest order, as she has published several works on theology, education and biography Miss Porter, a novelist of the lirst rank in the powers of eloquent composition, whose Thaddeus of Warsaw and other works, will long he standards of the language. . Miss Benger, who figures with equal distincton as a novelist, historian, and critic. Miss Grant, who has distinguished herself in morals, philosophy, and the belles lettres. Mrs. Ma rcet, who has proved her powers of mind in her conversations on Natural Philosophy, &c. Mrs. Lowry, w ho writes and lectures with great ability on min rnlogy and geology. M iss Owenson, (L:idy Morgan,) whose j eloquent writing, moral and political reason ing, are not surpassed bv any author of her time. Mrs. Wakefield, compiler of many useful and ingoukitts w orks for the use of children and schools. Mrs. Ibortson, whose discoveries with the microscope on tli Physiology of plants, rank her high among experimental philoso phers. Miss Hcrschell, whose ingenuos, and industry in astronomical observation have obtained her a splondidr equitation through out the civilized world. Miss A ikin, niece to Mrs. Barbauld, who, soaring above productions of more taste and lancy, has in her memoirs ol Elizabeth, pro ved her powers in history and philosophy. Miss Graham, the able writer of several volumes of travels which arc distinguished tor their sound philosophy and enlightened views of society M. IP Arbly, (Mi s Burney,) whose Eve lina, Cecilia, Camille, and other novels, place her among the first and most original writers of any age. Miss Baillie, whose plays on the Passion - and other productions are higly est emed by every person of goed taste. Besides others of less celebrity, hut per haps equal merit, whose names are not pre sent to the recollection of the writer. PROBLEMS FOR FINDING THE LATITUDE, nr E. 11. BURRXTT, A. M. Between the months of April and September, in our latitude, it is impossible to measure a meridian altitude of the sun on the arc of a sextant, from the ne cessity of using an AltTiFicf ai. Horizon, which doubles the angle of observation. The solutions of spherical Trigonometry, in the commutation of right and oblique angles, exhibit other methods of determining the lati tude equally correct, though less simple, than by a meri dian altitude of the sun. Os these, the following are the most osefu), METHOD FIRST. Civcu two equal altitudes of the sun, observed the same day, with the interval of time between the ob servations, to find the latitude. Rule. —To the cotangent of the declination, add the cosine of half the internal in degrees, the sum will be the cotangent of are first. To the cosecant of the declination, add the sine of the altitude, and arc first, and call their sum the cosine of arc second. If the latitude and declination arc of the same name, that is, on the same side of the equator, then the sum of arcs first and second will be the latitude; b>-t if of contrary names, their difference w ill be the latitude. JVote. It is the advantage of this method, that the ex act time of observation is not required, as in Bowditcb and others, for determining the latitude by double alti tudes. The true apparent time is an element very often difficult to obtain accurately ; not so in measuring an interval of a few hours. N. B. The corrections for semidiameter and refrac tion must be applied to the observed altitude, in this and the following methods, as usual in other cases.' — [Fide Mackay Long. Yol. I. pp. 3tS.J METHOD SECOND. Given two altitudes of the sun, and the times of ob servation, to find the Latitude and Declination. Ride. —To the ar. co. of the log. of the difierenre of the natural versed sines of the times from noon re duced to degrees, add the log. of the versed sine of the reatest interval, and the log. of the differences of the natural sines of the true altitudes, the sum will be the log. of arc first To the constant log 5.3010300, add the two last mentioned logs, the sum will be the log of arc second. The sum of arc first, and the natural sine of the least altitude, will be the natural cosine of art third ; and this natural cosine being subtracted from arc se cond, leaves the natural cosine of arc fourth. Half the sum of arcs third and fourth, will be ie Latitude, and half the.r difference, will be tin Declination. .Vote. This method, though less simple that, the for-j nvr, bus the advantage of giving tlie sun’s declination. I wit tout which the Latitude cannot be computed 1 v other method. GEORGIA STATESMAN, TUESDAY JUNE, 13, 182 G. METHOD THIRD. The sin 's Declination, two altitudes, and the time between the observations to find the Latitude of the place. It! LE. 1. To the sine of ur.’.s polar ditarce, or co-declination, add the sire- of half the intend in degrees, and the sum, rejecting ten in the index, gives the sin ot hi If arrfiret. Cosine of polar distance minus cotangent of half the interval in degrees, gives cotungeihof arc second. 3. Fror' the h. If sum of arc first and the complements of the two altitudes, subtree! e ch of th se quantities separate!), anti reserve the remainders ; add together the sun- of the I.i t sum tfj found, and the least remaind r, or th- difference between thi half sum and comp, ofleast alt. ; Cud the arilgn-tical cotnple inent of thrir sum, add it to the sines of the two other remainders, and half the logarithm will be the tangent of an angle, the double ofwhieb, mm’j.t are second, will give arc. third 4. Cosine arc third, p! oj the tangent complement of greatest altitude, gives tangent err fourth. 5. To the ar. co. of cos. arc fourth, add cosine comp, ol the greatest altitude and the cosine of tlie difference obtwcell arc fourth and sun’s poiar distance, and their sum mil In the cosine comp, of Latitude required. .Vote. This solution, though apparently very tedious, is purely mathematical and exact; and when w ( take into consideration the peculiar advantages of tl.is method over any of the proceeding, its length will appear very much diminished. With the s me data for finding the Latitude, this is the easiest method extant, and the illustrating example is so full and minute, that it must he thoroughly understood from s. single opera tion. Tin possible difficulties which may cnibat -ass every other na 'hod eun newr happen to this, in Me thod Ftr.sr, if the observer has secured an anti-meridian altitude of the sun, and fail, by r is on of clouds, or otherwise, to note the passing instant when the evening altitude is exactly equal to the observed altitude oi the morning, his labor, for that day, becomes entirely lost, and his observation unavailing. 'Method Second is liable to a difficulty equally uncertain of remedy ; to wit—the difficulty of obtain ing, at the moment of need, the true time, without which, in this case, every other step is void. Ft time pieces are sufficiently accurate for this purpose without a correction by equal alti'udcs ; amt this, as before mentioned, maybe thwarted by the momentary intervention of a cloud. In Method Thi there it no such embarrassment. It matters not at vvliat periods, either in the forenoon or afsernoon, the two altitudes arc taken, nor whether your watch or time-piece be an hour too fast or too slow; provkUd the elapsed time be tween the observations be correctly known. METHOD FOURTH. To find the latitude by an altitude of the north polar star, taken at any hour of the night. Rule. —Add the apparent time of observation to the sun’s right ascension ; the sum (rejecting 24 hours if necessary) will be the right ascension of the meridian, or mid-heaven ; with which enter Table I, and apply the correction corresponding to the true altitude of the star, according to the direction contained in the Table, and it will give the ajt/n vrimalr (aiilvde. Enter table If, vvbb the, appioximr.t latitude, thus found at top of the page, and the same right ascension of tin tncriilr.it in the right er left hand columns, and there will be found a corwcttoii, which being added to the approximate latitude, will give the tine latitude of the place of observation. Note. —As the differences of altitude between the, polar star and the poie,jcontaine( in Table I, are par ticularly adapted to the beginning of the year 1826, a correction becomes necessary for til subsequent years ; this correction is found by multiplying the annual variation by tlie number of ye *s, and pirts of a year, elapsed between the beginning of 1826, and Ibe given day; the product being applied to the corresponding correction of altitude, by addition, or subtraction, according to the sign expressed ag instil, will gre tlie true correction of the polar star’s altitude at the given time ; with which proceed as above directed. Os all the heavenly bodies, the polar star seems best calculated for finding the tutkuds in the northern hemisphere ; because a single altitude, taken at any hour of the night by a careful obsener, in a clear atmos phere, will give the latitude to a sufficient degree of accuracy, provided th- apparent tme of observation be known within a few minutes of the truth; however, an error in the apparent time, even os considerable as 20 minutes, will not affect the latitude to the value of half a minute, when tlie polar stir is on the meridian, either above or below the pole ; nor will it ever affect the latitude more than 3 minutes and 42 seconds, cvcn«at the star’s greatest distance from the meridian. EXAMPLE I. Iu North Latitude, May 19, at 9h 59m 4s. A. M. and r .’h Dm 595. P. M. the true altitude ot‘ the sun’s centre was 50’ 25', and the declination 19 39 ; required the latitude. (By Method First.) Cotangent of Declination 19° 39' 0" 10.4472496 Cosine of half the interval 30 14 0 9.9365047 Cotangent of Arc First 22 27 16 10.3837543 Cosecant of declination 19 39 0 10.47.3.3073 Sine of altitude 50 25 0 9.8868846 Sine of arc first (22 27 1C f 9.5820050 Cosine of Arc Second (28 54 36 > 9.9421969 Latitude required 51 21 52 EXAMPLE 11. At 8h 30m. A. M. the true altitude of the sun’s centre was 38° 19', and at lOh A. M. the altitude was 50° 25' ; required the Latitude and Declination. (By Method Second.) EXAMPLE 111. Given the sun’s declination, 19' 39'N. ; first altitude in the forenoon 38* 19, and an hour and a half later, 50 25' , to find the Latitude of the pLce. Sine of polar distance 70° 21' 0" 9.9739422 Sine ol half interval 11 15 0 9.2902357 Sine 10 35 13~ oT^GITTFI) Arc First, 21 10 26 Cosine of polar distance 70’ 21' 0 ' 9.6266927 Cotangent of half the interval 11 15 0 10.7013382 Cotangent of Arc Second 86 10 24 8.8253545 Complement of least altitude 51 41 0 Complement of greatest altitude 39 35 0 Arc First 21 19 26 ij 112 26” 26 Half sum 56 c 13' 13" 56 13 13 56° 13' 13" 39 35 0 51 41 0 2 10 26 2d rem. 16 38 13 lstrem. ~~4 Ti 3d rem *35 2 47 Sine of half sum % 56 26 26 9.9196958 Sine of first, or least remaindev 4 32 13 8.8981866 18.8178824 Arithmetical complement 1.1821176 Sine of second remainder 16° 38' 13" 9.4568307 Sine of third remainder 35 2 47 9.7590930 Divide by 2) 20.39804 lT Tangent 57 41 33 To7l 990206" / Doubled 2 773 23 6 Auc Second, subtract 86 10 24 Arc Third ~29 12 42 Cosine = 9.9409260 Tang. Comp. Greatest Altitude 39 35 0 9.9173911 Tang. Arc Fourth 35 48 56 97858317! Cos. Arc Fourth 35* 40' 56" = 9.9099700 ar. co. =• 00900300 Cosine complement of greatest Alt. 39 35 0 = 9.8868846 Pol. dist. 70’21' 0" arc 4th 35° 48'56" = 34° 32’ 4” cos. 9.9158142 Gives Cosine 38° 38' 6", = complement of Lat. 51’ 21' 54" 9.8927288 Suppose it were now required to compute the true apparent times of observa tion in the third example—as follows : Latitude 51° 21' 54" 38’ 38' 6" Co-latitude Altitude 50 25 0 39 35 0 Co-altitude Declination 19 39 0 70 21 0 Co-declination -i)l48 34 6 Half sum 74 17 3 74 17 3 74 17 3 Co-lat. -38 38 6 Co-dec. 70 21 0 co-alt. 39 35 0 2d rem 35 38 57 lstrem. 3 56 33d rem 34 42 3 Sinecf half sum 74 17 3 0.9834534 Sine of third rem. 34 42 3 9.7553347 19.7387532 Arith. cornp. 0.2612118 Sine second rem. 35 38 57 $.7655348 Sine first rem. 3 56 3 8.3365883 l) Iff. 8631354 Tang: of half the hour /_ from noon 15 7 0 14315677 which doubled 2 and Converted into time gives 15) SO 14 ( h Oni 545. or ?li £9in is. for the apparent time of observation, fiom which subtract an hum - and q half, and it gives the time of first observation. By the best astronomical tables, the declination of the north polar star, at the beginning of the present year, (1826) was 88' 23' 11 ; its distance from the true pole ol the heavens i 76' 43 , and its right ascension Oh. 58m. 495.; con sequently when the right ascension ol the meridian is oh ohm 4hs polar star is 1° 6 58 49 polar star is 1 12 58 49 polar star is 1 18 58 49 polar star is 1 24 *8 49 polar star is 1 Whence it is evident that this star, in its motion about the true pole of the heavens, is continually changing its altitude, as shewn in table I. Tables for finding the Latitude, by the North Table I. Table 11. Annual | jj Rt. as. Latitude. lof the polar variation i ,; of the itr\ ’Uy r * Add. hrbtitact. [gtar’r alt, oj correc. J |j meridian. GH, 45. hms|Amsh ms\ h m s ~ „ « I !sms ,„ |, „ 0.58.49 0.58.49 12.58.49 12.58.49 1.36.43 —19.45 i 0.58.490. 00. 0 1. 0 0.45 13. 0 12.45 1.36.42 19.4 j 1.30 0. 10. 1 1.10 0.35 12.10 12.35 1.36.35 19.2 2. 0 0. 40. 5 1.20 0.25 13.20 12.25 1.36.12 18.9 2.30 0. 8 0.10 130 0.15 13.30 12.15 1.35.39 18. G 3.0 0.14 0.17 LiO 0. 5 13.40 12. 5 1.34.56 18.2 j I; 3.30 0. 20 0. 24 1.50 23.55 13.50 11.55 1.34. 1 17.7 4.0 0.27 0.33 2.0 23.45 14.0 11.45 ! 1.32.55 17.3 4.20 0.31 0.38 2.10 23.35 14.10 11.35 1.31.38 IC.B 4.40 036 0.43 2.20 2325 1420 11.25 1.30.11 16.3 5.0 0.40 0.48 2730~ 23H5 14.30 17.15 1.28.33 15.8 5.20 0. 43 (1~55 "2.40 23.5 14.40 11.5 1-26.44 15.2 5.40 0.46 0.25 2.50 22.55 14.50 10.55 1.24.46 14.5 6.0 0.48 0.58 3. 0 22.45 15. 0 10.45 1.22.35 13.9 6.20 0.49 1. 0 3.5 22.40 15.5 10.40 1.21.28 13.6 6-40 0.50 1. 1 3.7(7 22!35 TTTTo 10.35 1.20.16 13.2 ~7. 0 0. 50 T7~l 3.15 22.30 15.15 10.30 1.19.3 12.9 7.20 0.49 0.59 3.20 22.25 15.20 10.25 1.17.49 12.6 7.40 0.47 0.57 3.25 22.20 15.25 10.20 1.16.31 12.2 8.0 0.44 0.54 3.30 22.15 15.30 10.15 1 15.11 11.9 8.20 0.41 0.50 3.35 22.10 15.35 10.10 1.13.48 11.5 8.40 0. 38 (T 46 3.40 22.5 1540 10.5 1.12.24 11.1 9.0 0.34 0.42 3.45 22.0 15.45 10.0 1.10.58 10.7 920 0.30 0.36 3.50 21.55 15.50 9.55 1. 9.29 10.4 9.40 0-26 0.31 .3.55 21.50 15.55 9.50 1. 7.59 10.0 10.0 0.21 0.26 4. 0“ 21.45 16. 0 9.45 1. 6.26 9.6 10.30 0. 15 0. 19 4. 5 21.40 16. 5 9.40 1. 4.52 9.2 11. 5 0. 9 0.11 4.10 21.35 16.10 9.35 1. 3.15 8.8 11.35 0. 40. 6 415 21 30 16.15 9.30 1. 1.36 8.5 12. 5 0. 2O’ 2 4.20 21.25 16.20 9.25 1. 0.56 8.0 12.58.49 0. 0 0.0 4.30 21 15 16.30 9.15 0.57.30 7.2 13.40 0. 20. 2 4.35 21.10 16.35 9.10 0.55.44 6.8 14.10 0. 40. 6 4.40 21. 5 16.40 9.5 0.53.56 6.3 14.40 0. 90.11 4.45 21. 0 16.45 9. 0 0.52. 7 5.9 15.15 0.150.19 LSO 20.55 16.50 8.55 0 50.17 5.5 i 4.55 20.50 16.55 8.50 0.48.26 5.1 I 16. 5 026 0.31 5.0 20.45 17.0 8.45 0.46.31 4.6 L 16.25 0.30 0.36 5. 5 20.40 17. 5 8.40 0.44.36 4.2 ! 16.45 0.34 0.42 5.10 20.35 17 10 835 0.42.40 3.8 17.5 0.38 0.34 STI~ 20.30 17 15 8.30 0.40.43 3.3 17.25 Ol 5750 5.20 20.25 17.20 8.25 0.38.44 2 9 17 45 0.44 054 5.25 20.20 17.25 8.20 0.36.44 2.5 18.5 0.47 0.57 5.30 20.15 17.30 8.15 0.34.43 2.0 18.25 0.49 0.59 6.35 20 10 17.35 8.10 0.32.41 1.6 18.45 0. 50 1. 1 540 20. 5 17.40 8.5 0.30.39 1.1 19. 5 050 1~1 5.45 20. 0 17.45 8.0 0.28.35 0.7 19.25 0.49 1. 0 5.50 19.55 17.50 7.55 0.26.30 —0.03 19.45 0.48 0.58 5.55 19.50 17.55 7.50 0.24.24 .0.0 920.5 0.46 0.55 6. 0 19.45 18. 0 7.45 .0.22.18 -f 0.7 Jj20.25 0.43 0.52 6 5 lITTo 18. 5 7.40 0.20.1! 1.1 ■ 2o’. 45 0. 40 0~48 6.10 19.35 18.10 7.35 0.18.4 1.5 i 21- 5 0.36 0.43 615 19.30 18.15 7.30 0.15.55 2.0 21.25 0.31 0.38 6.20 19.25 18 20 7.25 0.13.47 2.4 j 21.45 0/27 0.33 6.25 19.20 18.25 7.20 0.11.37 2.8 | 22.15 0.20 0. 24 T 730 19.15 18 30 7.15 0. 9.28 3X 22.45 OTR OT7 6.35 19.10 18.35 7.10 0.7 18 37 23.15 0. 80 10 6.40 19. 5 18.40 7. 5 0. 5. 8 4.2 23.45 0. 4 0 5 6-45 19. 0 18 45 7. 0 0. 2.58 4.6 0.15 0. 1 0 1 650 18.58. 3 18.60 6.58. 30. 0.47 5.0 j 1 0.58.49 0. On 0 6.58.49 18.58.49118.58.49 6.68.49 0. 0. 0 -}- 5.0 j 1 * DD TABLE ill A NEW AND CORRECT TABLE. Exhibting the time and quantity of the Elongation of the North Star, on the Ist day of every month, from 1825, to 1830, inclusive, corrected for Precession, Aberration, and Nutation. Time of Star’s Greatest Elongation Elongation. Elongation. Elongation. Elongation. I Elongation. Elongation. Ist day of passing meridian East or West. 1825. 1826. 1927. 1828. 1828. 1830. II SI H M DMSDMS DM9 DM S DMS D M t January 6 12 P. m. W 0 13 a. m. 1 55 41 1 55 18 1 54 56 1 54 32 1 54 9 1 53 46 February 4 0 r. M. W 9 59 p. m. 1 53 43 1 55 20 1 54 57 1 54 34 1 54 11 1 53 47 March '210p.m.W89p.m.1554815526155 3 1 54 39 1 54 16 1 53 62 April 0 14 a. m. E 6 13 a m. 1 55 59 1 55 36 1 55 14 1 54 50 1 54 27 1 54 3| May 10 23 a. m. E 4 24 a. m. 1 66 10 1 55 47 1 65 26 1 55 2 1 54 39 1 54 15 June 8 21 a. m. E 2 22 a. m. 1 56 16 1 55 53 1 55 32 1 55 8 1 54 42 1 54 21 July 6 17 a m E 0 18 a. m. 1 56 18 1 55 55 1 55 34 1 55 10 1 54 48 1 54 24 August 4 15 v. m. E 10 14 p. m. 1 56 13 1 55 6L 1 55 29 1 55 5 1 54 43 1 54 19! September 2 19 p. m. E 8 18 p. m. 1 56 4 1 55 12 1 55 20 1 54 56 1 54 33 1 51 9! October 0 31 a m. W 6 30 a. m. 1 55 51 1 55 28 1 55 7 1 54 43 1 54 20 1 53 56 November 10 33 a. m W 4 34 a. m. 1 55 38 1 55 15 1 54 53 1 54 31 1 54 7 1 53 43! December 8 29 a. m. W 2 30 a. m. 1 55 26 1 55 3 1 54 42 1 54 18 1 53 56 1 53 31 which is a tangent to the true level, at the 13 112. 70 AL To find the difference In tween the true and app.—nt level, for any given distance ! - ! 30< 80 4255 divide lltu squirt of the distance by the diameter ~ .earth. } ° ‘ ’1» 149. 90 5586 Ur ' ll,fl^. nce **‘ wce . n tl,e tn,e am ’parent level for one mile,or 16 *7O. 100 6649 v .id*, ghee’ o.aV/ofa o ?« c ewth i", trv'; X'j: ■‘'T'? A -fctr div.auo ,0 it. p. . ..."correction 4 f * b *° 8 ,Bcto ’ *• * thf sqwwe of «v 36' 43 s above the true pole. 36 43 west of true pole. 36 43 below the tme pole. 36 43 east of the true pole. 36 43 above the true pole again. Explanations. TABLE IV. _ Curvature of the Earth Table 111 exhibits the angle 01 —— which the North Star makes S'! Inches. | ~ | Inches, with the true m.rutian at its u I | ° | greatest Eastern or Western 1 0,00125 27~0 A elongation, supposing the ob- Qn ’ . u ’ y| server to stand on the 33d de- ~ 28 0,38 gree of North latitude, hut will 3 0,01125 29 1,05 answer with equal accuracy for 4 0,02 30 1 12 any other point in Georgia, by 50 03 31 MQ adding to the numbers in the — ; - I,la table I -J- second for every 6 0,04 32 1.27 minute the latitude of the place 7 0,06 33 135 is greater than 33 deg. or sub- 80 08 34 1 ’44 trading if less. 0O ID or tIZ The time of the polar star’s 1,53 arriving at its greatest Eastern W_. _3® 1 ,62 or Western elongation is giv- 11 0 15 ~37 1 71 en in the table for the first i<> n ’io *’'* day of every month only. For 38 1,80 the intermediate days, subtract ' 0 61,21 39 1,91 4 minutes for each day, from 14 0,24 40 200 the tabular time; thus, requir- 15 028 ,l o'ao led t!,e time of elongation on - ithe bih of May— 4 times 6is 1 b 0,32 50 3,12 24 minutes, which taken from 17 0,36 55 378 the tabular time 4h. 24 m. 18 040 fin An gives the tune of elongation at , n " 1 r 4 ’ °° 4 o’clock A. M. of the given *3 0,40 65 5,31 day. The same rule applies 20 0,50 70 6,12 to the star’s passing the men- 21 (iTT TTTo dian. As the whole change of „„ ’ ‘ elongation in a month does n ~~ ">6O 80 8,00 amount to quite half of ass- 23 0,67 85 9,03 cond, its daily variation te*y 24 0 72 90 10A ;bc neglected. The letters £. ac n ’ 7R or ~ and W. shew whether th. 95 11,28 elongation be East or West. ,260,84 100 12,50 To find tiie declination of thet “ S'. " T compass needle by this table, i- H*‘B ht *" 2 Height observe the true bearing of the ’ : Feet - ST in feet, pole star at its greatest elonga- ~ | ok Tj iqo tion, and if its elongation be i ! n 1Q 01 - east, add it to the apparent \ 1B declination, but if west, sub- 4 10.6 19 21C tract it from the apparent or 6 46.6 20 266 observed declination, and the 6 i3.9 ‘>s 415 sum or iliffcrencc will he the 7 YL c 7,,. rriQ true variation of the compass. ‘ 3D 5.154 1 8 42A 35 814 Levelling. 9 53.8 ‘ 40 1064 The true level is a curve 10 66.4 4^1346 which cither coincides with, or .>o n a r Ac, is parallel to, the surface of * 80 ~ ,>0 water at rest. 12 95.4 60 239- No. 26. polar Star.