4 CONTENTS AND ILLUSTRATIONS. 



Page. 



Determination of areas by planimeter 78 



Land Office surveys 81 



Resurveys 83 



Cancellation of misleading marks 83 



Physiographic features 85 



ILLUSTRATIONS. 



Page. 



FIG. 1. Forest Service standard compass 10 



2. Standard pocket compass 15 



3. Lines of equal magnetic variation in the United 



States 17 



4. Positions of Polaris, Big Dipper, and Cassiopeia 18 



5. Plane-table method in which the table is set up at all 



the stations 24 



6. Plane-table method in which the table is set up at 



two stations and the remaining three are located 



by intersections 25 



7. Plane-table method of locating points on both sides of 



a base line which are to be occupied later and the 



survey extended 26 



8. Plane-table method of finding location from three 



points 27 



9. Method of sighting with standard hypsometer 29 



10. Areas of a section containing a compass error of 0.25. 32 



11. Ranger-station plat 55 



12. Standard planimeter 78 



13. Rectangular system of Land Office surveys 81 



14. Names of physiographic features 85 



