Leveling Rod Leveling Rod BS L₂ BS TP BM, Elev. of TP, Difference in Elev. between and BM₂ BM Elev of BM,(known) (Do not copy the illustration or drawing) Table: Determination of Elevation STATION BS HI FS ELEVATION 100 m BM1 1.60 m TP1 1.47m 0.85 TP2 1.67 m 0.78 TP3 1.54 m 0.89 BM2 0.75 2. Arithmetic Check. To check the accuracy of the arithmetical computations, add all backsights as well as all the foresights. The difference between these two sums must be equal to the difference in elevation between the initial and final points of the level line. (Show computations on the computed height of instrument and the elevation of the certain station or point.) Leveling Rod L₁ FSI HI, Horizontal Line of Sight FS BM₂ Elev. of BM₂