242 GEOGRAPHIC TABLES AND FORMULAS. [bull. 214. 
Table 23. — Corrections for curvature and refraction, infeet=0.574 {distance, miles)' 1 . 
[Difference in feet between the apparent and true level at distances varying from 1 to 66 miles.] 
Distance, 
miles. 
Difference in feet for — 
Distance, 
miles. 
Difference in feet for— 
Curvature. 
Refrac- 
tion. 
Curvature 
and 
refraction. 
Curvature. 
Refrac- 
tion. 
Curvature 
and 
refraction. 
1 
0.7 
0.1 
0.6 
34 
771. 3 
108. 
663. 3 
2 
2.7 
0.4 
2.3 
35 
817.4 
114.4 
703. 
3 
6.0 
0.8 
5.2 
36 
864. 8 
121. 1 
743.7 
4 
10.7 
1.5 ! 
9.2 
37 
913. 5 
127.9 
785.6 
5 
16.7 
2. 3 
14.4 
38 
'963. 5 
134.9 
828.6 
6 
24.0 
3.4 
20. 6 
39 
1,014.9 
142. 1 
872. 8 
7 
32.7 
4.6 
28. 1 
40 
1,067.6 
149. 5 
918.1 
8 
42 7 
6.0 
36. 7 
41 
1, 121.7 
157. 
964.7 
9 
54.0 
7.6 
46. 4 
42 
1, 177. 
164.8 
1,012.2 
10 
66.7 
9.3 
57. 4 
43 
1,233.7 
172.7 
1,061.0 
11 
80.7 
11.3 
69. 4 
44 
1,291.8 
180.8 
1,111.0 
12 
96.1 
13.4 
82.7 
45 
1,351.2 
L89.2 
1,162.0 
13 
1 12. 8 
15.8 
97.0 
46 
1,411.9 
107.7 
1, 214. 2 
14 
130. 8 
18.3 
112. 5 
47 
1, 474. 
206. 3 
1,267.7 
15 
150.1 
21. 
129.1 
48 
1,537.3 
215 2 
1, 322. 1 
16 
L70.8 
23.9 
146.9 
49 
1,602.0 
224. 3 
1,377.7 
17 
L92.8 
27.0 
L65.8 
50 
1,668.1 
233. 5 
1,434.6 
is 
216. 2 
30.3 
1S5.9 
51 
1 , 735. 5 
243. 
1 , 402. 5 
111 
240. 9 
33. 7 
207. 2 
52 
1 , S04. 2 
252. 6 
1,551.6 
20 
266. 9 
37.4 
229. 5 
53 
1,874.:; 
202. 4 
1,011.9 
21 
294. 3 
41.2 
253. 1 
54 
1.015.7 
272. 4 
1,673.3 
22 
: 522.9 
45. 2 
277.7 
55 
2,018.4 
2S2. li 
1,735. s 
23 
353.0 
49.4 
303.6 
56 
2, 092. 5 
202.0 
1,790.0 
24 
384. 3 
53.8 
330. 5 
57 
2, 107.0 
303.5 
1,864.4 
25 
417.0 
58. 4 
358.6 
58 
2, 244. 6 
314.2 
1,930.4 
26 
451.1 
63.1 
388. 
59 
2, 322. 7 
325.2 
1,997.5 
27 
486. 4 
j 68.1 
418. 3 
60 
2, 402. 1 
336.3 
2, 065. 8 
28 
523. 1 
73.2 
449.9 
61 
■ 2,482.8 
7 
347. 6 
2, 135. 2 
29 
561. 2 
78.6 
482.6 
62 
| 2,564.0 
359. 1 
2,205.8 
30 
600.5 
84.1 
516.4 
63 
2,648.3 
370.8 
2,277.5 
31 
641.2 
89.8 
551. 4 
64 
2, 733. 
382.6 
2,350.4 
32 
683.3 
95.7 
587.6 
65 
2,819.1 
394. 7 
2, 424. 4 
33 
726.6 
101.7 
624.9 
66 
2, 906. 5 
406.9 
2, 499. 6 
