go ENGINEERING ON THE FARM 



convergence of the meridians, this point is less than 6 

 miles from the principal meridian. The next tier of town- 

 ships is carried north in the same manner, and when the east 

 line of the third tier of townships is carried north, at the 

 northeast corner of each township a line is run east as well 

 as west to establish the north boundary of the fourth or 

 east tier of townships, since the guide meridian forms the 

 east boundary of that tier. 



At the time the base line, principal meridian, standard 

 parallel, guide meridians, and township corners are surveyed, 

 all corners, including the section and quarter-section cor- 

 ners, are established on these lines. The legal width of a 

 township, 6 miles, is correct on the south side of the 24-mile 

 area, but on the north side of the area the township widths 

 are less than 6 miles because of convergence. The line that 

 is run east or west to the corner that has previously been 

 established is a random line, and no permanent corners are 

 placed upon it. As soon as the location of the random 

 line is known with reference to the corner which is to be 

 intersected, the line is corrected and the corners established 

 on the true line. 



Convergency due to curvature increases with the latitude 

 and is as follows for a tract 6 miles wide and 6 miles long 

 on the indicated parallels: 



Lat. 44. Convergency 70 . 1 Iks. 



Lat. 45. Convergency 72 . 6 Iks. 



Lat. 46. Convergency 75-2 Iks. 



Lat. 49. Convergency 83 . 5 Iks. 



Offsets to locate a parallel when run as a prolongation 

 of a line having an angle of 90 with the meridian at the 

 starting point would be as follows for a location near 45 

 North Latitude: 



1 mile o . 67 f t. 



2 miles 2 . 66 ft. 



3 miles 5 . 99 ft. 



4 miles 10.65 ft. 



5 miles 16 . 64 ft. 



