246 GEOGRAPHIC TABLES AND FORMULAS. [bull. 214. 
Table 24. — For obtaining differences of altitude for any minute, etc. — Continued. 
2°. 
Corrections 
for curva- 
1 
2 
3 
4 
5 
6 
7 
8 
J) 
ture, refraction 
and 
height of instrument." 
1 

184.4 
368.8 
553 
738 
922 
1,106 
1,291 
1,475 
1,659 
1 
185. 9 
371.8 
558 
744 
930 
1,116 
1,301 
1,487 
1,673 
Miles. 
Feet 
Miles. 
Fed. 
2 
187.5 
374.9 
562 
750 
937 
1,125 
] , 312 
1,500 
1,687 
1.6 
6 
10.2 
64 
3 
189.0 
378.0 
567 
756 
945 
1,134 
1,323 
1,512 
1,701 
2.1 
7 
10.3 
65 
4 
190. 5 
381.1 
572 
762 
953 
1,143 
1, 334 
1,524 
1,715 
2. 5 
8 
10.4 
67 
5 
192. 1 
384.1 
576 
768 
960 
1,152 
1,344 
1, 537 
1,729 
2.8 
9 
10.5 
68 
6 
193.6 
387.2 
581 
774 
968 
1, 162 
1,355 
1, 549 
1,742 
3.1 
10 
10.6 
69 
7 
195.1 
390. 3 
585 
781 
976 
1,171 
1,366 
1, 561 
1, 756 
3.4 
11 
10.7 
70 
8 
196.7 
393.4 
590 
787 
983 
1,180 
1,377 
1,573 
1,770 
3.6 
12 
10.8 
71 
9 
198. 2 
396.4 
595 
793 
991 
1,189 
1,388 
1,586 
1,784 
3.8 
13 
10.9 
73 
10 
199.8 
399.5 
599 
799 
999 
1,199 
1,398 
1,598 
1,798 
4.1 
14 
11.0 
74 
11 
201.3 
402. 6 
604 
805 
1,006 
1,208 
1,409 
1,610 
1,812 
4.3 
15 
11.1 
75 
12 
202. 8 
405. 7 
609 
811 
1,014 
1,217 
1,420 
1,623 
1,826 
4.5 
16 
11.2 
77 
13 
201. 4 
408.8 
613 
818 
1, 022 
1,226 
1,431 
1,635 
1,839 
4.7 
17 
11.3 
78 
14 
205. 9 
411.8 
618 
824 
1,030 
1 , 235 
1,441 
1,647 
1,853 
4.8 
18 
11.4 
79 
15 
207. 5 
414.9 
622 
830 
1,037 
1,245 
1,452 
1,660 
1,867 
5.0 
19 
11.5 
80 
16 
209. 
418.0 
627 
836 
1,045 
1,254 
1,463 
1 , 672 
1,881 
5.2 
20 
11.6 
82 
17 
210.5 
421. 1 
632 
842 
1,053 
1,263 
1,474 
1,684 
1,895 
5.4 
21 
11.7 
83 
18 
212. 1 
424.1 
(536 
848 
1, 060 
1,272 
1,484 
1,697 
1,909 
5.5 
22 
11.8 
84 
19 
213.6 
427.2 
641 
854 
1,068 
1,282 
1,495 
1,709 
1,932 
5.7 
23 
11.9 
86 
20 
215. 1 
430.3 
645 
861 
1,076 
1,291 
1,506 
1,721 
1,936 
5.8 
24 
12. 
87 
21 
216. 7 
433.4 
650 
867 
1, 083 
1,300 
1,517 
1,733 
1,950 
6.0 
25 
12.1 
89 
22 
218. 2 
436. 4 
655 
873 
1,091 
1,309 
1,528 
1,746 
1,964 
6.1 
26 
12.2 
90 
23 
219.8 
439.5 
659 
879 
1,099 
1,319 
1,538 
1, 758 
1,978 
6.3 
27 
12. 3 
91 
24 
221.3 
442. 6 
664 
885 
1,106 
1,328 
1,549 
1,770 
1, 992 
6.4 
28 
12.4 
93 
25 
222. 8 
445. 7 
669 
891 
1,114 
1,337 
1,560 
1,783 
2, 006 
6.5 
29 
12.5 
94 
26 
224. 4 
448.7 
673 
897 
1, 122 
1,346 
1,571 
1,795 
2, 019 
6.7 
30 
12.6 
96 
27 
225. 9 
451.8 
678 
904 
1, 130 
1, 355 
1,581 
1,807 
2, 033 
6.8 
31 
12.7 
97 
28 
227. 5 
454.9 
682 
910 
1,137 
1,365 
1,592 
1, 820 
2, 047 
6.9 
32 
12.8 
99 
29 
229.0 
458. 
687 
916 
1,145 
1,374 
1,603 
1, 832 
2,j)61 
7.0 
33 
12.9 
100 
30 
230. 5 
461.1 
692 
922 
1,153 
1,383 
1,614 
1,844 
2,075 
7.2 
34 
13.0 
102 
31 
232. 1 
464.1 
696 
928 
1,160 
1,392 
1,624 
1,857 
2, 089 
7.3 
35 
13.1 
103 
32 
233. 6 
467.2 
701 
934 
1,168 
1,402 
1,635 
1,869 
2,102 
7.4 
36 
13. 2 
105 
33 
235. 1 
470.3 
705 
941 
1,176 
1,411 
1,646 
1,881 
2, 116 
7.5 
37 
13.3 
106 
34 
236. 7 
473.4 
711 
947 
1,183 
1, 420 
1,657 
1,893 
2,130 
7.6 
38 
13.4 
108 
35 
238. 2 
476.4 
715 
953 
1,191 
1,429 
1,668 
1,906 
2, 144 
7.8 
39 
13.5 
109 
36 
239. 8 
479.5 
719 
959 
1,199 
1,439 
1,678 
1,918 
2, 158 
7.9 
40 
13.6 
111 
37 
241.3 
482. 6 
724 
965 
1,207 
1,448 
1,689 
1, 930 
2, 172 
8.0 
41 
13.7 
112 
38 
242. 8 
485.7 
729 
971 
1,214 
1,457 
1,700 
1,943 
2,186 
8.1 
42 
13.8 
114 
39 
244.4 
488.8 
733 
978 
1, 222 
1,466 
1,711 
1,955 
2,199 
8.2 
43 
13.9 
115 
40 
245.9 
491.8 
738 
984 
1,230 
1,476 
1,721 
1,967 
2,213 
8.3 
44 
14.0 
117 
41 
247. 5 
494.9 
742 
990 
1,237 
1,485 
1, 732 
1, 980 
2, 227 
8.4 
45 
14.1 
119 
42 
249. 
497.0 
747 
996 
1,245 
1,494 
1,743 
1,992 
2,241 
8.5 
46 
14.2 
120 
43 
250. 5 
501.1 
752 
1, 002 
1,253 
1, 503 
1,754 
2, 004 
2, 255 
8.6 
47 
14.3 
122 
44 
252. 1 
504. 2 
756 
1,008 
1,260 
1, 512 
1,765 
2, 017 
2, 269 
8.7 
48 
14.4 
124 
45 
253. 6 
507. 2 
761 
1,014 
1,268 
1,522 
1,775 
2, 029 
2,283 
8.8 
49 
14.5 
125 
46 
255. 2 
510. 3 
765 
1,021 
1, 276 
1,531 
1,786 
2,041 
2, 296 
8.9 
50 
14.6 
127 
47 
256.7 
513. 4 
770 
1,027 
1,283 
1,540 
1,797 
2, 054 
2, 310 
9.0 
51 
14.7 
129 
48 
258. 2 
516. 5 
775 
1,033 
1,291 
1,549 
1,808 
2, 066 
2, 324 
9.1 
52 
14.8 
130 
49 
259. 8 
519.5 
779 
1,039 
1,299 
1, 559 
1,818 
2,078 
2, 338 
9.2 
53 
14.9 
132 
50 
261.3 
522.6 
784 
1,045 
1,307 
1,568 
1,829 
2,091 
2,352 
9.3 
54 
15.0 
134 
51 
262. 9 
525. 7 
789 
1,051 
1,314 
1,577 
1,840 
2, 103 
2, 366 
9.4 
55 
15. 1 
135 
52 
264. 4 
528. 8 
793 
1, 058 
1, 322 
1,586 
1,851 
2,115 
2, 380 
9.5 
56 
15.2 
137 
53 
265. 9 
531.9 
798 
1, 064 
1,330 
1,596 
1,862 
2, 127 
2, 393 
9.6 
58 
15.3 
139 
54 
267.5 
534. 9 
802 
1,070 
1,337 
1,605 
1,872 
2, 140 
2,407 
9.7 
59 
15.4 
141 
55 
269. 
538.0 
807 
1,076 
1, 345 
1,614 
1,883 
2, 152 
2,421 
9.8 
60 
15. 5 
142 
56 
270. 6 
541. 1 
812 
1,082 
1,353 
1,623 
1,894 
2, 164 
2, 435 
9.9 
61 
15.6 
144 
57 
272. 1 
544.2 
816 
1,088 
1, 360 
1,633 
1,905 
2, 177 
2, 449 
10.0 
52 
15.7 
146 
58 
273.6 
547. 3 
821 
1,095 
1,368 
1,642 
1,915 
2, 189 
2, 463 
10.1 
63 
15.8 
148 
59 
275.2 
550. 3 
826 
1,101 
1,376 
1,651 
1,926 
2,201 
2,477 
15.9 
16.0 
150 
151 
60 
276.7 
553.4 
830 
1,107 
1,384 
1,660 
1,937 
2, 214 
2,490 
a For all distances under 1.6 miles the correction may be taken as +5 feet. 
i assumed 4.5 feet. 
Height of instrument 
