256 GEOGRAPHIC TABLES AND FORMULAS. [bull. 214. 
Table 24. — For obtaining differences of altitude for any minute, etc. — Continued. 
12°. 
Corrections for < 
3urva- 
1 
2 
3 
4 
5 
6 
7 
8 
9 
ture, refractior 
l, and 
height of instrument." 

1, 122 
2,245 
3,367 
4,489 
5,612 
6,734 
7,856 
8,978 
10, 101 
1 
1,124 
2,248 
3,372 
4,496 
5,620 
6,743 
7,867 
8,991 
10,115 
Miles. 
Feet. 
Miles. 
Feet. 
2 
1,126 
2, 251 
3,377 
4, 502 
5, 628 
6, 753 
7,879 
9, 004 
10, 130 
1.6 
6 
10.2 
64 
3 
1,127 
2, 254 
3,381 
4,508 
5, 636 
6, 763 
7, 890 
9,017 
10, 144 
2.1 
7 
10.3 
65 
4 
1,129 
2,257 
3,386 
4, 515 
5,644 
6, 772 
7,901 
9,030 
10, 159 
2.5 
8 
10.4 
67 
5 
1,130 
2, 261 
3,391 
4, 521 
5,652 
6, 782 
7,912 
9,043 
10, 173 
2.8 
9 
10.5 
68 
6 
1,132 
2,264 
3,396 
4, 528 
5,660 
6, 792 
7, 924 
9, 056 
10,188 
3.1 
10 
10.6 
69 
7 
1,134 
2, 267 
3,401 
4,534 
5,668 
6,801 
7,935 
9, 068 
10,202 
3.4 
11 
10.7 
70 
8 
1, 135 
2,270 
3,405 
4,541 
5, (576 
6,811 
7,946 
9,081 
10,216 
3.6 
12 
10.8 
71 
9 
1,137 
2,274 
3,410 
4,547 
5,684 
6,821 
7,957 
9,094 
10, 231 
3.8 
13 
10.9 
73 
10 
1,138 
2,277 
3,415 
4,554 
5,692 
6,830 
7,969 
9,107 
10, 245 
4.1 
14 
11.0 
74 
11 
1,140 
2,280 
3,420 
4, 560 
5,700 
6,840 
7,980 
9, 120 
10, 260 
4.3 
15 
11.1 
75 
12 
1,142 
2,283 
3,425 
4,566 
5,708 
6, 850 
7,991 
9,133 
10,274 
4.5 
16 
11.2 
77 
13 
1,143 
2,286 
3,430 
4,573 
5,716 
6,859 
8, 002 
9, 146 
10, 289 
4.7 
17 
11.3 
78 
14 
1,145 
2, 290 
3,434 
4,579 
5, 724 
6,869 
8,014 
9,158 
10,303 
4.8 
18 
11.4 
79 
15 
1,146 
2, 293 
3,439 
4, 586 
5,732 
6, 879 
8, 025 
9,171 
10, 318 
5.0 
19 
11.5 
80 
16 
1,148 
2, 296 
3,444 
4,592 
5,740 
6,888 
8,036 
9,184 
10,332 
5.2 
20 
11.6 
82 
17 
1,150 
2, 299 
3,449 
4,599 
5, 748 
6,898 
8,047 
9,197 
10, 347 
5.4 
21 
11.7 
83 
18 
1,151 
2, 302 
3, 454 
4, 605 
5, 756 
6, 907 
8, 059 
9, 210 
10, 361 
5. 5 
22 
11.8 
84 
19 
1,153 
2,306 
3,459 
4,611 
5, 7<J4 
6,917 
8,070 
9,223 
10, 376 
5.7 
23 
11.9 
86 
20 
1,154 
2,309 
3,463 
4,618 
5,772 
6,927 
8,081 
9,236 
10, 390 
5.8 
24 
12.0 
87 
21 
1, 156 
2, 312 
3,468 
4, 624 
5, 780 
6,936 
8, 092 
9, 249 
10, 405 
6.0 
25 
12.1 
89 
22 
1,158 
2, 315 
3, 473 
4, 631 
5,788 
6,946 
8,104 
9,261 
10, 419 
6.1 
26 
12.2 
90 
23 
1,159 
2,319 
3,478 
4, 637 
5, 796 
6,956 
8, 115 
9, 274 
10, 434 
6.3 
27 
12.3 
91 
24 
1,161 
2, 322 
3,483 
4,644 
5, 804 
6, 965 
8, 126 
9, 287 
10,448 
6.4 
28 
12.4 
93 
25 1, 163 
2, 325 
3,487 
4, 650 
5,812 
6, 975 
8,138 
9,300 
10,463 
6.5 
29 
12.5 
94 
26 1 1,164 
2,328 
3, 492 
4,656 
5,821 
6,985 
8,149 
9, 313 
10,477 
6.7 
30 
12.6 
96 1 
27 
1,166 
2, 331 
3,497 
4, 663 
5,829 
6,994 
8, 160 
9, 326 
10, 491 
6.8 
31 
12.7 
97 
28 
1, 167 
2,335 
3, 502 
4,669 
5,837 
7,004 
8,171 
9,339 
10, 506 
6.9 
32 
12.8 
99 
29 
1,169 
2,338 
3, 507 
4,676 
5,845 
7,014 
8,183 
9, 351 
10, 520 
7.0 
33 
12.9 
100 
30 
1,171 
2,341 
3,512 
4,682 
5, 853 
7,023 
8, 194 
9,364 
10, 535 
7.2 
34 
13.0 
102 
31 
1,172 
2,344 
3,516 
4,689 
5, 861 
7,033 
8, 205 
9,377 
10, 549 
7.3 
35 
13.1 
103 
32 
1,174 
2,348 
3, 521 
4,695 
5,869 
7,043 
8, 216 
9, 390 
10,564 
7.4 
36 
13.2 
105 
33 
1,175 
2,351 
3,526 
4,702 
5, 877 
7, 052 
8, 228 
9,403 
10, 579 
7.5 
37 
13.3 
106 
34 
1,177 
2,354 
3,531 
4,708 
5, 885 
7, 062 
8, 239 
9,416 
10, 593 
7.6 
38 
13.4 
108 
35 
1,179 
2,357 
3, 536 
4,714 
5,893 
7,072 
8,250 
9,429 
10,608 
7.8 
39 
13.5 
109 
36 
1,180 
2, 360 
3,541 
4,721 
5, 901 
7,081 
8,262 
9,442 
10, 622 
7.9 
40 
13.6 
111 
37 
1,182 
2, 364 
3, 546 
4,727 
5, 909 
7,091 
8,273 
9, 455 
10,637 
8.0 
41 
13.7 
112 
38 
1,183 
2, 367 
3, 550 
4,734 
5,917 
7,101 
8,284 
9, 468 
10, 651 
8.1 
42 
13.8 
114 
39 
1,185 
2,370 
3, 555 
4,740 
5,925 
7,110 
8, 296 
9,481 
10, 666 
8.2 
43 
13.9 
115 
40 
1,187 
2,373 
3, 560 
4,747 
5,933 
7,120 
8,307 
9,494 
L0,680 
8.3 
44 
14.0 
117 
41 
1,188 
2,377 
3, 565 
4, 753 
5, 942 
7, 130 
8,318 
9,506 
10, 695 
8.4 
45 
14.1 
119 
42 
1,190 
2, 380 
3, 570 
4, 760 
5, 950 
7,140 
8, 329 
9, 519 
10,709 
8.5 
46 
14.2 
120 
43 
1,192 
2,383 
3, 575 
4,766 
5,958 
7,149 
8,341 
9, 532 
10, 724 
8.(1 
47 
14.3 
122 
44 
1,193 
2,386 
3,579 
4,773 
5,966 
7, 159 
8, 352 
9, .545 
10,738 
8.7 
48 
14.4 
124 
45 
1,195 
2,390 
3, 584 
4,779 
5,974 
7,169 
8,363 
9, 558 
10, 753 
8.8 
49 
14.5 
125 
46 
1,196 
2, 393 
3,589 
4,785 
5, 982 
7,178 
8, 375 
9, 571 
10, 767 
8.9 
50 
14.6 
127 
47 
1,198 
2, 396 
3, 594 
4,792 
5, 990 
7,188 
8,386 
9,584 
10,782 
9.0 
51 
14.7 
129 
48 
1,200 
2,399 
3,599 
4,798 
5,998 
7,198 
8,397 
9,597 
10, 796 
9.1 
52 
14.8 
130 
49 
1,201 
2,402 
3,604 
4,805 
6,006 
7, 207 
8,409 
9,610 
10, 811 
9.2 
53 
14.9 
132 
50 
1,203 
2,406 
3,608 
4,811 
6,014 
7,217 
8,420 
9,623 
10, 825 
9.3 
54 
15. 
134 
51 
1,204 
2,409 
3,613 
4,818 
6, 022 
7,227 
8,431 
9,636 
10, 840 
9.4 
55 
15.1 
135 
52 
1,206 
2,412 
3,618 
4,824 
6,030 
7,236 
8, 442 
9,648 
10, 855 
9.5 
56 
15.2 
137 
53 
1,208 
2,415 
3, 623 
4,831 
6,038 
7,246 
8,454 
9,661 
10,869 
9.6 
58 
15.3 
139 
54 
1,209 
2,419 
3, 628 
4,837 
6,046 
7,256 
8, 465 
9,674 
10, 884 
9.7 
59 
15.4 
141 
55 
1,211 
2,422 
3,633 
4,844 
6, 055 
7,265 
8,476 
9,687 
10, 898 
9.8 
60 
15.5 
142 
56 
1,213 
2,425 
3,638 
4,850 
6,063 
7,275 
8,488 
9,700 
10,913 
9.9 
61 
15.6 
144 
57 
1,214 
2,428 
3, 642 
4,857 
6,071 
7, 285 
8,499 
9,713 
10, 927 
10.0 
62 
15.7 
146 
58 
1,216 
2,431 
3,647 
4,863 
6,079 
7, 294 
8,510 
9,726 
10,942 
10.1 
63 
15.8 
148 
59 
1,217 
2,435 
3,652 
4,869 
6,087 
7,304 
8,521 
9,739 
10, 956 
15.9 
16.0 
150 
151 
60 
1,219 
2,438 
3,657 
4,876 
6,095 
7,314 
8,533 
9,752 
10, 971 
a For all distances under 1.6 miles the correction may be taken as + 5 feet, 
is assumed 4.5 feet. 
Height of instrument 
