80 A MANUAL FOR NORTHERN WOODSMEN 
on distances from one quarter to one third of a mile, giving 
results which are accurate to within a few feet. 
Example and Reduction of Readings. 1' on rod cut off 
at distance of 100'. In computation, correction made for 
1' instrumental constant. True horizontal distance and 
difference of elevation between points both worked out. 
Height of instrument over station obtained at each setting 
and center hair for vertical angle read at same height on 
rod. 
Observed 
Computed 
Bearing 
Rod 
Reading 
Vert. 
Angle 
Distance 
Diff. 
Elev. 
Elev. 
N. 5° E. 
2.00' 
+ 1° 30' 
200.86' 
+ 5.27' 
5.27' 
N. 5° E. 
1.80' 
+ 4° 10' 
179.84' 
+ 13.12' 
18.39' 
N. 5° E. 
1.05' 
00 
, + 
103.94' 
+ 14.61' 
33.00' 
N. 5° E. 
1.50' 
— 30' 
150.98' 
— 1.31' 
31.69' 
j_ 
635.62' 
31.69' 
Computation. First shot, with v. a. of 1° 30', rod reading 2.00'. 
Add .01' for instrument constant, making 2.01', for corrected rod 
reading. From table the horizontal distance for 1' rod reading is 
found to be 99.93' the difference of elevation 2.62'. For 2.01' rod 
reading the elements are 99.93 X 2.01 and 2.62 X 2.01 or 200.86' 
and 5.27', as above. 
Second shot, 1.80 + .01, = 1.81, corrected rod reading. 
For v. a. 4° 10' and rod reading 1', horizontal distance 99.47 
and diff. elev. 7.25 are found in the tables. 99.47 X 1.81 and 
7.25 X 1.81 = 179.84 and 13.12. 
Similarly for succeeding shots 
4. Uses of the Transit 
To Take the Bearing of a Line. Set up over the first 
point, level the instrument, free the needle, and turn the 
telescope toward the other point. Read the bearing in the 
same way as with a compass. 
When set up on the forward one of two points, exactly 
the same bearing may be read as if the instrument were 
