24 



Instructions to Field Parties, 



Table for reducing odometer readings to fortieths of a mile — Cont'd. 



Plane-table traversing. — It is sometimes impossible to furnish the 

 field party with a base map of proi)er accuracy. In all such cases 

 the party will be supi)lied with a plane-table outfit, and a traverse 

 base map of the area is to be constructed in the field by the soil- 



