TRAIL SURVEYS. 59 



is also called to the circular of the General Land Office, 

 September 7, 1906, " Regulations Governing Entries 

 within Forest Reserves." 



A cooperative agreement between the Departments 

 of the Interior and Agriculture , da ted Sep tember 1 9 , 1 9 1 1 , 

 to avoid duplication or unnecessary work in surveying 

 forest homestead claims, provides that instead of two 

 surveys, as heretofore required, there shall be but one 

 survey, and that it may be made by a forest officer, 

 designated by and acting under the direction of the 

 surveyor general, "who will exercise supervision in 

 every case as to the manner of the execution of the 

 survey with reference to the running of lines and the 

 establishment of monuments to mark the same." 



Such surveys are for the approval of the surveyor 

 general and acceptance by the General Land Office. 

 The instructions of the surveyor general will be fol- 

 lowed in these cases, even though they conflict entirely 

 or in part with the methods of the Forest Service. 



TRAIL, SURVEYS. 



In surveying for railways, roads, or trails, the vertical 

 deflection of the line is always expressed in per cent. 

 Thus, a 5 per cent grade means a rise of 5 feet in 100 

 feet of horizontal distance. The horizontal deflection 

 of the line is always expressed in degrees. Thus, a rail- 

 way may have a 3 curve, which is a horizontal deflec- 

 tion of 3 in 100 feet, from chord to chord, or a road 

 may have a change in direction of 3 at the junction 

 of two courses. Percentage of grade and degrees of 

 azimuth should never be confounded, as very serious 

 errors will result. The terms are never interchangeable. 



