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0 <br />CURVE TABLES. <br />Published by KEUFFEL & ESSER CO. <br />].HOW TO USE • CURVE TABLES. <br />Table I. contains Tangents and Externals to a P curve. Tan. and <br />�. Ext. to any other radius maybe found nearly enough, bydividing the Tan. <br />or Ext. opposite the given Central Angle by the given degree of curve. <br />'.To find Deg. of Curve, having the Central Angle and Tangent: <br />Divide Tan. opposite the given Central Angle by the given Tangent. <br />. To find Deg. of Curve, having the Central Angle and4 External: <br />Divide Ext. opposite the given Central Angle by the given External. <br />To find Nat. Tan. and Nat. Ex. Sec: for any angle by Table I.: Tan. <br />or Est. of twice the given angle divided by the radius of a P curve will <br />be'the Nat. Tan. or Nat. Ex. Sec. <br />EXAMPLE., <br />Wanted a Curve with an Eat. of about 12 ft. Angle <br />of Intersection or I. P. =23° 20' to the R.- at Station <br />542+72. <br />Ext. in Tab.:I, opposite 23° 20' =120.87 <br />120.87 =12 =10.07. Say a. lOP Curve. . <br />Tan. in Tab. I opp. 23° 20'= 1183.1 <br />1183.1+10=118.3l.' <br />Correction for A: 23° 20' for a 10° Cur. =0.16 <br />118.31+0.16=118.47 =corrected Tangent. <br />(If,corrected Ext. is.re juiced find in same way) <br />Ang. 23°20'=23.33 ,=10=2.3333=.L. C. . <br />2° 19,'=def: for sia. 542 I. P. =sta. 542+72 <br />40491-1--' " " +50 Tan. = 1 .18.47 <br />90 49j'�� +50 B. C. =sta. -541+53.53 <br />110 40'-_--` " " " 543 -F. L. C. _ . 2 .33.33 <br />86.86 E. C.=Sta. 543 ► 86.86 <br />100-53.53=46.47X3'(def. for 1 ft. of 10° Cur.) -_'-139.41'= <br />2°49;'=def. for sta.,542. <br />Def. for 50 ft: =2° 30' fora 10° Curve.' <br />Def. for 36.86 ft. =1° 50F for a 10° Curve. <br />LP.Anq.23 �ppn <br />