284 GEOGRAPHIC TABLES AND FORMULAS. [bull. 234. 
Table 26. — For obtain'mg differences of altitude for any minute, etc. — Continued. 
14°. 
Corrections for 
3urva- 
1 
2 
» 
4 
5 
6 
7 
8 
9 
ture, refraction 
, and 
heightof instrument." 

1,316 
2,633 
3,949 
5,266 
6,582 
7,899 
9,215 
10,532 
11,848 
1 
1,318 
2,636 
3,954 
5,272 
6,590 
7,909 
9, 227 
10, 545 
11, 863 
Miles. 
Feet. 
Miles. 
Feet. 
2 
1,320 
2,639 
3,959 
5, 279 
6,599 
7,918 
9,238 
10,558 
11,877 
1.6 
6 
10.2 
64 
3 
1,321 
2,643 
3,964 
5,285 
6, 607 
7, 928 
9,249 
10,571 
11,892 
2.1 
7 
10.3 
65 
4 
1,323 
2,646 
3,969 
5,292 
6,616 
7,938 
9,261 
10, 584 
11, 907 
2.6 
8 
10.4 
67 
5 
1,325 
2,649 
3,974 
5,298 
6. 623 
7,948 
9,272 
10,*97 
11,923 
2.8 
9 
10.6 
68 
6 
1,326 
2,653 
3,979 
5, 305 
6,631 
7,957 
9,284 
10, 610 
11, 936 
3.1 
10 
10.6 
69 
7 
1,328 
2,656 
3,984 
5, 312 
6,639 
7,967 
9, 295 
10, 623 
11,961 
3.4 
11 
10.7 
70 
8 
1,330 
2,659 
3,989 
5, 318 
6,648 
7,977 
9,307 
10,636 
11,966 
3.6 
12 
10.8 
71 
9 
1,331 
2, 662 
3,993 
5, 325 
6, 656 
7,987 
9,318 
10, 649 
11,980 
3.8 
13 
10.9 
73 
10 
1,333 
2,666 
3,998 
5,331 
6, 664 
7,997 
9,329 
10, 662 
11,995 
4.1 
14 
11.0 
74 
11 
1,334 
2,669 
4,003 
5,338 
6, 672 
8,006 
9,341 
10, 675 
12,010 
4.3 
15 
11.1 
75 
12 
1,336 
2, 672 
4,008 
5, 344 
6,680 
8,016 
9, 352 
10,688 
12, 024 
4.5 
16 
11.2 
77 
i;i 
1,338 
2, 675 
4,013 
5,351 
6,688 
8,026 
9,364 
10,701 
12, 039 
4.7 
17 
11.3 
78 
14 
1,339 
2, 679 
4,018 
5,357 
6,697 
8,036 
9,375 
10, 715 
12,054 
4.8 
18 
11.4 
79 
15 
1,341 
2,682 
4, 023 
5,364 
6,705 
8,046 
9,387 
10, 728 
12, 069 
5.0 
19 
11.5 
80 
It; 
1,343 
2,685 
4,028 
5, 370 
6,713 
8,056 
9,398 
10, 741 
12, 083 
5.2 
20 
11.6 
82 
17 
1,344 
2,688 
4,033 
5,377 
6, 721 
8,065 
9,410 
10, 754 
12,098 
6.4 
21 
11.7 
83 
18 
1,346 
2,692 
4,038 
5,383 
6,729 
8,075 
9, 421 
10, 767 
12, 113 
6.5 
22 
11.8 
84 
19 
1,348 
2,695 
4,042 
5,390 
6,737 
8,085 
9,432 
10, 780 
12, 127 
5.7 
23 
11.9 
86 
20 
1,349 
2,698 
4,047 
5,397 
6, 746 
8,095 
9,444 
10, 793 
12, 142 
5.8 
24 
12.0 
87 
21 
1, 351 
2, 702 
4, 052 
5,403 
6,754 
8, 105 
9, 455 
10, 806 
12, 157 
6.0 
25 
12.1 
89 
22 
1,352 
2,705 
4,057 
5,410 
6, 762 
8,114 
9, 467 
10,819 
12, 172 
6.1 
26 
12.2 
90 
23 
1, 354 
2, 708 
4,062 
5,416 
6,770 
8, 124 
9,478 
10,832 
12, 186 
6.3 
27 
12.3 
91 
24 
1,356 
2, 711 
4,067 
5,423 
6,778 
8,134 
9,490 
10, 845 
12. 201 
6.4 
28 
12.4 
93 
25 
1,357 
2, 715 
4,072 
5, 429 
6,787 
8,144 
9, 501 
10, 859 
12,216 
6.5 
29 
12.5 
94 
26 
1,359 
2, 718 
4,077 
5, 436 
6,795 
8, 154 
9, 513 
10, 872 
12, 231 
6.7 
30 
12.6 
96 
27 
1,361 
2,721 
4,082 
5,442 
6,803 
8,164 
9, 524 
10,886 
12,245 
6.8 
31 
12.7 
97 
28 
1,362 
2,724 
4,087 
5,449 
6,811 
8,173 
9,536 
10,898 
12, 260 
6.9 
32 
12.8 
99 
29 
1,364 
2,728 
4,092 
5,455 
6,819 
8,183 
9,547 
10,911 
12, 276 
7.0 
33 
12.9 
100 
30 
1,366 
2,731 
4,097 
5,462 
6,828 
8,193 
9,559 
10, 924 
12, 290 
7.2 
34 
13.0 
102 
31 
1,367 
2,734 
4,101 
5, 469 
6, 836 
. 8, 203 
9,570 
10,937 
12,304 
7.3 
35 
13.1 
103 
32 
1,369 
2, 738 
4,106 
5,475 
6,844 
8,213 
9, .581 
10,950 
12,319 
7.4 
36 
13.2 
105 
33 
1,370 
2, 741 
4,111 
5,482 
6,852 
8, 223 
9, 693 
10, 963 
12, 334 
7.5 
37 
13.3 
106 
34 
1,372 
2,744 
4,116 
5,488 
6,860 
8,232 
9,604 
10, 976 
12, 349 
7.6 
38 
13.4 
108 
35 
1,374 
2, 747 
4,121 
5, 495 
6,868 
8,242 
9,616 
10, 990 
12, 363 
7.8 
39 
13.5 
109 
36 
1,375 
2,751 
4,126 
5, 501 
6,877 
8,262 
9, 627 
11,003 
12, 378 
7.9 
40 
13. G 
111 
37 
1,377 
2,754 
4,131 
5,508 
6,885 
8,262 
9,639 
11,016 
12, 393 
8.0 
41 
13.7 
112 
38 
1,379 
2,757 
4,136 
5,514 
6,893 
8,272 
9, 650 
11,029 
12, 408 
8.1 
42 
13.8 
114 
39 
1,380 
2,761 
4,141 
5,521 
6,901 
8, 282 
9, 662 
11,042 
12, 422 
8.2 
43 
13.9 
115 
40 
1,382 
2,764 
4,146 
5,528 
6,910 
8,291 
9,673 
11,055 
12,437 
8.3 
44 
14.0 
117 
41 
1,384 
2,767 
4,151 
5,534 
6,918 
8,301 
9,685 
11, 068 
12, 462 
8.4 
46 
14.1 
119 
42 
1,386 
2,770 
4,156 
5,541 
6,926 
8,311 
9,696 
11,081 
12, 467 
8.5 
46 
14.2 
120 
43 
1,387 
2,774 
4,160 
5,547 
6,934 
8,321 
9,708 
11,095 
12, 481 
8..6 
47 
14.3 
122 
44 
1,388 
2,777 
4,165 
5,554 
6,942 
8,331 
9.719 
11, 108 
12, 496 
8.7 
48 
14.4 
124 
45 
1,390 
2,780 
4,170 
5,560 
6, 951 
8,341 
9,731 
11,121 
12, 511 
8.8 
49 
14.5 
126 
46 
1,392 
2,784 
4,175 
5,567 
6, 959 
8,351 
9, 742 
11,134 
12, 526 
8.9 
60 
14.6 
127 
47 
1,393 
2,787 
4,180 
5,574 
6, 967 
8,360 
9,754 
11, 147 
12, 541 
9.0 
51 
14.7 
129 
48 
1,395 
2, 790 
4,185 
5,580 
6,975 
8,370 
9,765 
11,160 
12,555 
9.1 
62 
14.8 
130 
49 
1,397 
2, 793 
4,190 
6,587 
6,983 
8,380 
9,777 
11,173 
12, 670 
9.2 
53 
14.9 
132 
50 
1,398 
2,797 
4,195 
5,593 
6,992 
8,390 
9,788 
11,187 
12,586 
9.3 
54 
16.0 
134 
51 
1,400 
2,800 
4,200 
5, 600 
7,000 
8,400 
9,800 
11,200 
12,600 
9.4 
55 
15.1 
135 
52 
1,402 
2,803 
4,205 
5, 606 
7,008 
8,410 
9,811 
11, 213 
12,616 
9.5 
56 
15.2 
137 
53 
1,403 
2,807 
4,210 
5,613 
7,016 
8,420 
9,823 
11,226 
12,629 
9.6 
58 
15.3 
139 
54 
1,405 
2,810 
4,215 
5,620 
7,024 
8,429 
9,834 
11,239 
12, 644 
9.7 
59 
15.4 
141 
55 
1,407 
2,813 
4,220 
5,626 
7,033 
8,439 
9,8^6 
ll,2o2 
12, 669 
9.8 
CO 
15.6 
142 
56 
1,408 
2,816 
4,225 
5, 633 
7,041 
8,449 
9, 8o7 
11,266 
12, 674 
9.9 
61 
15.6 
144 
57 
1,410 
2, 820 
4,230 
5,639 
7,049 
8,459 
9,869 
11, 2^9 
12, 689 
10.0 
62 
15.7 
146 
58 
1,411 
2,823 
4,234 
5,646 
7,057 
8,469 
9,880 
11, 292 
12, 703 
10.1 
t;3 
15.8 
148 
59 
1,413 
2,826 
4,239 
5,653 
7,066 
8,479 
9,892 
11, 306 
12, 718 
16.9 
16.0 
150 
1 r;i 
60 
1,415 
2,830 
4,244 
5,659 
7,074 
8,489 
9,903 
11, 318 
12, 733 
1.1 J 
a For all distances under 1. 
is assumed 4.5 feet. 
miles the correction may be taken as + 5 feet. Height of instrument 
