DIFFERENCE OF ALTITtTDE. 



49 



TABLE 6. Difference of altitude between the "station" occupied by the 

 surveyor, of which the altitude is known, and a higher distant object 

 whose altitude is desired Continued. 



[Difference of altitude in feet add to station altitude.] 



This table is corrected for earth curvature, refraction, and the height of the instru- 

 ment used at the station (4J feet). 



23682 12 4 



