34 



A MANUAL FOR NORTHERN WOODSMEN 



the distribution. In any case the correction is applied so 

 as to help close the survey and not the reverse. This pro- 

 cess is called Balancing a Survey. 



The field notes of a closed survey, the latitudes and de- 

 partures as they reckon out, and the same balanced, are 

 given herewith. The reckoning is also given, and all is in 

 convenient arrangement. The latitudes and departures 



COMPUTING LATITUDES AND DEPARTURES 



in this case have been reckoned out not from the traverse 

 table, but from the table of logarithmic sines and cosines. 

 A little consideration, shows that the latitude of a course is 

 the cosine of its bearing multiplied by its distance, while 

 the departure is the product of the sine multiplied by the 

 distance. Now a table of sines and cosines gives values 

 to single minutes instead of for 15' bearings. Logarithmic 

 computation, too, shortens the process. This is, therefore, 

 the more convenient way of reckoning for transit work, or 

 for accurate compass surveying. 



When all but the final course has been run, it is in 

 some circumstances desirable to ascertain what course 

 to set in order to hit the starting point. This, too, may 

 readily be done by means of the figured latitudes and 

 departures. 



Thus, suppose that four courses of the above survey have 



