Mapping Soils and Alkali. 



23 



mileage. Each odometer is adapted to but one sized wheel. In 

 case it is impossible to obtain a vehicle with a wheel of the proper 

 size for the odometer you have, the readings must be corrected in 

 order to read miles. Should any other sized wheel be used, the 

 following formula will enable the proper correction to be made: 



ad 



X- 



A 



AVhere x is distance traver.sed in fortieths of a mile, d is the diame- 

 ter of the wheel to be used, d^ is the diameter of wheel to which 

 the odometer is adapted, and a is number of dial divisions as read 

 from odometer. 



The instruments furnished by this Bureau are nearly all adapted 

 to a 42-inch wheel. The following table will enable the proper 

 correction to be made when any other than a 42-inch wheel is 

 used. The figures in the first column are the dial divisions as 

 read from the odometer, and the figures in the other columns 

 give the distance traveled in fortieths of a mile. Chain scales 

 divided into forty parts to an inch are supplied for convenience 

 in platting distances as measured or calculated in this table. 



Table for reducing odometer readings to fortieths of a mile. 



Dial divisions. 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



46 



1.1 

 2.2 

 3.3 

 4.4 

 5. 5 



6.6 

 7. 7 

 8.8 

 9.9 

 11.0 



12.0 

 13.2 

 14.2 

 1-5.3 

 16.4 



