PROBLEMS 



279 



represented by diagonal lines. The measured interval 

 scales are shown on the left and right margins. Pick off 

 the proper measured interval on the left or right margin 

 and follow the horizontal line from this point on the meas- 

 ured interval scale to its intersection with the proper 

 off -vertical line. From here follow a vertical line to the 

 upper or lower margin, as the case may require, where 

 the vertical correction in feet is indicated. 



Table IX. — Example and Fokm of Notes for Versine Vertical 

 Correction Method 



