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.. I Sr H,I ; za sta , 01 Ik rp aA3' � l o 1l c( ¢ r7 oaS,�l7 P, /.77 e, ¢,Z 1. a � a _ 4 Ti- *1 Y" der _ 3•I7 !�7 7— i 7 wP- -- �d _ 5, .c ?47 /a2. -ca jai{ C. CURVE TABLES. • Published by KEUF'FEL 8& ESSER CO, HOW TO USE CURVE, TABLES. Table 1. contains Tangents and Externals to a 1° curve. Tan. and Ext. to any other radius may be found nearly enough, by dividing the Tan, or Ext. opposite the given Central Angle by the given degree of curve. To find Deg. of Curve, having the Central Angle and Tangent: Divide Tan. opposite the given Central Angle by the given Tangent. To find Deg..of Curve, having the Central Angle and External: Divide Ext. opposite the given Central Angle by the given External. To find Nat. Tan. and Nat, Ex. Sec. fox any angle by Table L: Tan, or, Ext. of twice the given angle divided by tlhe radius of"a P curve will be the Nat. Tan, or Nat. Ex. Sec. EXAMPLE. Wanted a Curve with an Ext. of about 12 ft. Angle of Intersection or I. P. =23' 20` to the It, at Station 542+72: Ext, in Tab. T opposite 23° 20'= 120.87 120.87-12=10.07. Say a lo' Curve. Tan. in Tab. I opp. 23° 20` 1183.1 1183.1-10 =118.31. Correction for A. 23° 20' for a 10' Cur. =0.16 118.31 x-0.16 =11.8.47 =corrected; Tan (If corrected Ext. is required find 1n same *ay) Ane. 23°20'=23.33°-10-2.3333=L. C. 2° 199'=def. forsta. 542 1. P. :sta. 542-1 72 40491 a' _ « -1-50 Tan, = 70 19z`= a rr r, 1 .18.47 a 543 004911= 13. C. = st.7. 541 +5T53a rr rc 350 + LC = 2 .33.33 100-53.53=46.47X3'(deef. for 1 t. of 543+86.86 Cur.) 543 6 2° 19a'=def, for sta. 542. Def. for 50 ft. =2° 30' for a 10° Curve. Def. for 36.86 ft. =1° 50j' for a 10° Curve.