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A MANUAL OF TOPOGRAPHIC METHODS. 



Table X. — For computing differences of attitude from angles of elevation or depression (applicable to scale 



of 1:30000). 

 [Prepared bj R. S. Woodward.! 



T!i»'„,.„„,.„ r in,, i ? +n''i+''i <"r angles of elevation. 

 Difference of altitnde= !_!„,; J A ^., ll .. 111 j lesol . lll . ]iri , ssl(m _ 



D = distanee in scale divisions B l a inch each; a =angle of elevatii 

 curvature and refraction. 

 Argument for //, is a. argument for !/■ is V. 



'depression; h , = 5U feet x tan a ; /i 2 =^correetion 



