252 GEOGRAPHIC TABLES AND FORMULAS. [bull. 214. 
Table 24. — For obtaining difference* of altitude for any minute, etc. — Continued. 
8° 
Corrections for curva- 
1 
2 
3 
4 
5 
6 
7 
8 
9 
ture, refraction 
, and 
height of instrument." 
/ 

742. 1 
1,484 
2,226 
2,968 
3,710 
4,452 
5,194 
5, 936 
6,678 
1 
743.6 
1,487 
2, 231 
2,974 
3,718 
4,462 
5, 205 
5,949 
6,693 
Miles. 
Feet. 
Miles. 
Feet, 
2 
745.2 
1,490 
2, 236 
2,981 
3, 726 
4,471 
5, 216 
5,962 
6,707 
1.6 
6 
10.2 
64 
3 
746.8 
1,494 
2, 240 
2, 987 
3,734 
4,481 
5,227 
5,974 
6,721 
2.1 
7 
10.3 
65 
4 
748.3 
1,497 
2, 245 
2, 993 
3, 742 
4,490 
5, 238 
5, 987 
6,735 
2.5 
8 
10.4 
67 
5 
749.9 
1, 500 
2, 250 
3,000 
3, 749 
4,499 
5,249 
5,999 
6,749 
2.8 
9 
10.5 
68 
6 
751. 5 
1,503 
2,254 
3,006 
3,757 
4, 509 
5,260 
6,012 
6,763 
3.1 
10 
10.6 
69 
7 
753. 
1,506 
2, 259 
3, 012 
3,765 
4,518 
5,271 
6, 024 
6,777 
3.4 
11 
10.7 
70 
8 
754. 6 
1,509 
2, 264 
3,018 
3,773 
4,528 
5, 282 
6,037 
6,791 
3.6 
12 
10.8 
71 
9 
756. 2 
1,512 
2,269 
3, 025 
3,781 
4,537 
5,293 
6,049 
6,806 
3.8 
13 
10.9 
73 
10 
757. 7 
1,515 
2,273 
3,031 
3,789 
4,546 
5,304 
6,062 
6,820 
4.1 
14 
11.0 
74 
11 
759.3 
1, 519 
2,278 
3,037 
3,797 
4,556 
5, 315 
6,074 
6,834 
4.3 
. 15 
11.1 
75 
12 
760.9 
1,522 
2, 283 
3,043 
3,804 
4,565 
5, 326 
6,087 
6,848 
4.5 
16 
11.2 
77 
13 
762. 4 
1,525 
2,287 
3, 050 
3, 812 
4,575 
5,337 
6,100 
6,862 
4.7 
17 
11.3 
78 
14 
764. 
1,528 
2, 292 
3,056 
3,820 
4,584 
5,348 
6, 112 
6, 876 
4.8 
18 
11.4 
79 
15 
765.6 
1,531 
2, 297 
;;, 062 
3,828 
4, 593 
5,359 
6,125 
6, 890 
5.0 
19 
11.5 
80 
16 
767.1 
1,534 
2,301 
3,069 
3, 836 
4,603 
5, 370 
6,137 
6, 904 
5.2 
20 
11.6 
82 
17 
768.7 
1,537 
2, 306 
3, 075 
3, 844 
4, 612 
5,381 
6,150 
6,918 
5.4 
21 
11.7 
83 
18 
770.3 
1,541 2,311 
3,081 
3,851 
4,622 
5, 392 
6, 162 
6,933 
5.5 
22 
11.8 
84 
19 
771.8 
1,544 
2, 316 
3,087 
;{, 859 
4,631 
5,403 
6,175 
6,947 
5.7 
23 
11.9 
86 
20 
773.4 
1,547 
2,320 
3,094 
3, 867 
4,640 
5,414 
6,187 
6,961 
5.8 
24 
12.0 
87 
21 
775.0 
1,550 
2, 325 
3, 100 
3,875 
4, 650 
5, 425 
6, 200 
6,975 
6.0 
25 
12.1 
89 
22 
776.6 
1,553 
2,330 
3, 106 
3, 883 
4,659 
5,436 
6, 212 
6,989 
6.1 
26 
12.2 
90 
23 
778.1 
1,556 
2,334 
3,112 
3,891 
4, 669 
5,447 
6,225 
7,003 
6.3 
27 
12.3 
91 
24 
779.7 
1,559 
2, 339 
15,119 
3,898 
4, 678 
5,458 
6, 237 
7,017 
6.4 
28 
12.4 
93 
25 
781.3 
1,562 
2, 344 
3,125 
3, 906 
4,688 
5, 469 
6, 250 
7,031 
6.5 
29 
12.5 
94 
26 
782. 8 
1,566 
2, 348 
3,131 
3,914 
4,697 
5,480 
6,263 
7,045 
6.7 
30 
12.6 
96 
27 
784.4 
1,569 
2, 353 
3,138 
3, 922 
4,706 
5,491 
6, 275 
7,060 
6.8 
31 
12.7 
97 
28 
786. 
1, 572 
2,358 
3,144 
3,930 
4,716 
5, 502 
6, 288 
7,074 
6.9 
32 
12.8 
99 
29 
787.5 
1,575 
2,363 
3, 150 
3,938 
4, 725 
5,513 
6,300 
7,088 
7.0 
33 
12.9 
100 
30 
789.1 
1,578 
2,367 
3, 156 
3, 945 
4, 735 
5,524 
6,313 
7,102 
7.2 
34 
13.0 
102 
31 
790.7 
1,581 
2,372 
3, 163 
3, 953 
4,744 
5, 535 
6, 325 
7,116 
7.3 
35 
13.1 
103 
32 
792. 2 
1,584 
2, 377 
3,169 
3, 961 
4,753 
5, 546 
6,338 
7,130 
7.4 
36 
13.2 
105 
33 
793.8 
1, 588 
2, 381 
3,175 
3, 969 
4,763 
5, 557 
6, 351 
7,144 
7.5 
37 
13.3 
106 
34 
795.4 
1,591 
2,386 
3, 182 
3,977 
4,772 
5, 568 
6, 363 
7, 159 
7.6 
38 
13.4 
108 
35 
796.9 
1,594 
2, 391 
3,188 
3, 985 
4,782 
5, 579 
6,376 
7,173 
7.8 
39 
13.5 
109 
36 
798.5 
1,597 
2,396 
3,194 
3, 993 
4,791 
5, 590 
6,388 
7,187 
7.9 
40 
13.6 
111 
37 
800.1 
1,600 
2, 400 
3, 200 
4,001 
4,801 
5,601 
6,401 
7, 201 
8.0 
41 
13.7 
112 
38 
801.7 
1,603 
2, 405 
3, 207 
4,008 
4,810 
5, 612 
6, 414 
7,215 
8.1 
42 
13.8 
114 
39 
803.2 
1,607 
2,410 
3,213 
4,016 
4,820 
5,623 
6,426 
7, 229 
8.2 
43 
13.9 
115 
40 
804.8 
1,610 
2,414 
3,219 
4,024 
4,829 
5, 634 
6,439 
7,243 
8.8 
44 
14.0 
117 
41 
806. 4 
1,613 
2, 419 
3, 226 
4, 032 
4,838 
5, 645 
6, 451 
7, 258 
8.4 
45 
14.1 
119 
42 
808.0 
1,616 
2,424 
3, 232 
4,040 
4,848 
5, 656 
6, 464 
7, 272 
8.5 
46 
14.2 
120 
43 
809. 5 
1,619 
2, 429 
3,238 
4,048 
4,857 
5,667 
6,476 
7,286 
8.6 
47 
14.3 
122 
44 
811.1 
1, 622 
2,433 
3,244 
4,056 
4, 867 
5,678 
6,489 
7,300 
8.7 
48 
14.4 
124 
45 
812. 7 
1,625 
2,438 
3,251 
4, 063 
4,876 
5, 689 
6, 501 
7,314 
8.8 
49 
14.5 
125 
46 
814.2 
1, 628 
2, 443 
3, 257 
4,071 
4,886 
5,700 
6,514 
7, 328 
8.9 
50 
14.6 
127 
47 
815.8 
1,632 
2, 447 
3, 263 
4,079 
4, 895 
5,711 
6, 527 
7, 342 
9.0 
51 
14.7 
129 
48 
817.4 
1,635 
2, 452 
3,270 
4,087 
4,904 
5, 722 
6, 539 
7,357 
9.1 
52 
14.8 
130 
49 
819.0 
1,638 
2,457 
3,276 
4,095 
4,914 
5,733 
6, 552 
7,371 
9.2 
53 
14.9 
132 
50 
820.5 
1,641 
2,462 
3,282 
4,103 
4, 923 
5,744 
6,564 
7,385 
9.3 
54 
15.0 
134 
51 
822. 1 
1,644 
2,466 
3,288 
4,111 
4, 933 
5,755 
6,577 
7,399 
9.4 
55 
15.1 
135 
52 
823.7 
1,647 
2, 471 
3, 295 
4,118 
4,942 
5, 766 
6,590 
7,413 
9.5 
56 
15.2 
137 
53 
825.3 
1,651 
2, 476 
3,301 
4,126 
4, 952 
5,777 
6, 602 
7,427 
9.6 
58 
15.3 
139 
54 
826.8 
1,654 
2, 481 
3,307 
4,134 
4,961 
5,788 
6,615 
7, 442 
9.7 
69 
15.4 
141 
55 
828.4 
1,657 
2, 485 
3,314 
4,142 
4,970 
5,799 
6,627 
7,456 
9.8 
60 
15.5 
142 
56 
830.0 
1,660 
2, 490 
3,320 
4,150 
4,980 
5,810 
6,640 
7,470 
9.9 
61 
15.6 
144 
57 
831. 5 
1,663 
2, 495 
3,326 
4, 158 
4,989 
5,821 
6, 652 
7,484 
10.0 
62 
15.7 
146 
58 
833.1 
1,666 
2, 499 
3,332 
4, 166 
4,999 
5,832 
6, 665 
7,498 
10.1 
63 
15.8 
148 
59 
834.7 
1,669 
2,504 
3,339 
4,173 
5, 008 
5,843 
6,678 
7, 512 
15.9 
16.0 
150 
151 
60 
836.3 
1,673 
2, 509 
3,345 
4,181 
5,018 
5,854 
6,690 
7, 526 
a For all distances under 1.6 miles the correction may be taken as + 5 feet, 
is assumed 4.5 feet. 
Height of instrument 
