268 GEOGKAPHIC TABLES AND FORMULAS. [bull.234. 
Table 25. — Corrections for cnrralKre (ititl rrfrocliov, hi feet=^OjT74 {distance, iniles)^. 
[Difference in feet between the apparent and trne level at distances varying from 1 to 66 miles.] 
Distance, 
miles. 
Difference in feet for— 
Distance, 
miles. 
Difference in feet for— 
Curvatnre. 
Refrac- 
tion. 
Curvatnre 
and 
refraction. 
Curvatnre. 
Refrac- 
tion. 
Curvature 
and 
refraction. 
1 
0.7 
0.1 
0.6 
34 
771.3 
108.0 
663. 3 
2 
2.7 
0.4 
2.3 
35 
817.4 
114.4 
703. 
3 
(). 
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 
157.0 
964.7 
9 
54.0 
7.6 
46.4 
42 
1,177.0 
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 
189.2 
1,162.0 
18 
112.8 
15.8 
97.0 
46 
1,411.9 
197.7 
1,214.2 
14 
130. 8 
18.3 
112.5 
47 
1, 474. 
206. 3 
1,267.7 
15 
150.1 
21.0 
129.1 
48 
1, 537. 3 
215 2 
1, 322. 1 
16 
170.8 
23.9 
146.9 
49 
1,602.0 
224. 3 
1,377.7 
17 
192.8 
27.0 
165.8 
50 
1,668.1 
233. 5 
1,434.6 
18 
216.2 
30.3 
185.9 
51 
1, 735. 5 
243. 
1 , 492. 5 
19 
240.9 
33. 7 
207.2 
52 
1, 804. 2 
252. 6 
1,551.6 
20 
266. 9 
37.4 
229.5 
53 
1,874.3 
262.4 
1,611.9 
21 
294.3 
4L2 
253.1 
54 
1,945.7 
272.4 
1,673.3 
22 
322.9 
45.2 
277.7 
55 
2,018.4 
282. 6 
1,735.8 
23 
353. 
49.4 
303.6 
56 
2, 092. 5 
292.9 
1, 799. 6 
24 
384. 3 
53. 8 
330. 5 
57 
2, 167. 9 
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 
388.0 
59 
2, 322. 7 
325. 2 
1, 997. 5 
27 
486.4 
68.1 
418. 3 
60 
2, 402. 1 
336. 3 
2, 065. 8 
28 
523. 1 
73.2 
449.9 
61 
2, 482. 8 
347. 6 
2, 135. 2 
29 
561.2 
78.6 
482.6 
62 
2, 564. 9 
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 
