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CURVE TABLES. <br />Published by KEUFFEL Ss ESSER CO. <br />HOW TO USE CURVE TABLES. <br />Table I. contains Tangents and Externals to a 11 curve. Tan. and <br />Ext. to any other radius may be found nearly enough, by dividing theTan. <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 and External: <br />Divide Ext. opposite the given Central Angle by the given External. <br />To find Nat. Tan. and Nat. Ex. See. for any angle by Table L: Tan. <br />or Ext. of twice the given angle divided by the radius of a 1° curve will <br />be the Nat. Tan. or Nat. Ex. Sec. <br />EXAMPLE. <br />Wanted a Curve with an Ext. of about 12 ft. Angle <br />of Intersection or 1. P.=230 20' to the R. at Station <br />542+72.- <br />Ext. <br />42+72.Ext. in .Tab. I opposite 23' 2(Y =120.87 <br />120.87+12=10.07.- Say a 10° Curve. <br />Tan. in Tab. I opp. 23° 20'=1183.1 <br />10=118.31. <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 required find in same way) <br />Ang. 23°20'=23:33°=10=2.3333=1_. C. <br />2° 19," =' for sta. 542 1. P. =sta. 542+72 <br />4° 49; rc cc cc +50 Tan. = 1 • .18.47 <br />543 <br />9°493'= c u <br />+50 B. C.=eta. 541+53.53 <br />543+ 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° 19," def. for sta. 542. <br />Def. for 50'ft. =2° 30' for a 10° Curve. <br />Def. for 36.86 ft. =1° 5012' for a 10° Curve. <br />