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I 6.4e,cH ' JvY/,,v, I W l�=oea <br />D/ <br />AM140 <br />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 1° curve. Tan. and <br />Ext. to any other radius maybe found nearly enough, by dividing 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 and 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 Ext. of twice the given angle divided by the radius of a- I` 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 I. P. =239 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 10° Curve. <br />Tan. in Tab. I opp. 23° 20'= 1183.1 <br />1183.1=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=L. C. <br />2° 19" = def. f or sta. 542 1. P: = sta. 542+72 <br />40 4911= " 0/ f/ +50 Tan. = 1 .18.47 <br />70 19j'= " <br />543 B C.=sta. 541--53.53 <br />90 491'= " " <i +50 <br />L. C.= 2 .33.33 <br />110 40'= " "1- <br />86.86 E. C. =Sta. 543-1-86.86 <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' fora 10° Curve. <br />Def. for 36.86 ft. =1° 50k' for a 10° Curv& <br />6 <br />