GANNETT] GEOGEAPHIC TABLES AND FORMULAS. 275 
Table 26. — For obiain'uKj differences of altitude for atuj mliviite, c/c— Continued. 
50 
Correction.s for 
3urva- 
1 
2 
3 
4 
5 
H 
7 
s 
y 
ture, refraction 
, and 
height of instrument.a 

461.9 
924 
1,386 
1,848 
2,310 
2, 772 
3,234 
3,696 
4, 1.57 
1 
463.5 
927 
1,390 
1,854 
2,317 
2, 781 
3,244 
3, 708 
4,171 
Miles. 
Feet. 
Miles. 
Feet. 
2 
465. 
930 
1,395 
1,860 
2, 325 
2,790 
3,255 
3,720 
4,185 
1.6 
6 
10.2 
64 
3 
466. 6 
933 
1,400 
1,866 
2,333 
2, 800 
3, 266 
3,733 
4,199 
2.1 
7 
10.3 
65 
4 
468.1 
936 
1,405 
1,873 
2,341 
2,809 
3,277 
3,745 
4,213 
2.5 
8 
10.4 
67 
5 
469.7 
939 
1,409 
1,879 
2,348 
2,818 
3,288 
3, 757 
4,227 
2.8 
9 
10.5 
68 
6 
471.2 
942 
1,414 
1, 885 
2, 356 
2,827 
3,299 
3,770 
4, 241 
3.1 
10 
10.6 
69 
472.8 
946 
1,419 
1,891 
2,364 
2,837 
3,309 
3, 782 
4,2,55 
3.4 
11 
10.7 
70 
8 
474.3 
949 
1,423 
1,897 
2,372 
2, 846 
3, 320 
3, 795 
4,269 
3.6 
12 
10.8 
71 
9 
475.9 
952 
1,428 
1,904 
2,379 
2,855 
3,331 
3,807 
4,283 
3.8 
13 
10.9 
73 
10 
477.4 
955 
1,432 
1,910 
2,387 
2, 865 
3,342 
3,819 
4,297 
4.1 
14 
11.0 
74 
11 
479.0 
958 
1,437 
1,916 
2, 395 
2, 874 
3,353 
3,832 
4,311 
4.3 
15 
11.1 
75 
12 
480.5 
961 
1,442 
1,922 
2, 403 
2,883 
3, 361 
3,844 
4,325 
4.5 
16 
11.2 
77 
13 
482.1 
964 
1,447 
1,928 
2, 410 
2, 892 
3,375 
3, 857 
4,339 
4.7 
17 
11.3 
78 
14 
483.6 
967 
1,451 
1,935 
2,418 
2, 902 
3, 385 
3,869 
4, 353 
4.8 
18 
11.4 
79 
15 
485.2 
970 
1,456 
1,941 
2, 426 
2, 911 
3,396 
3,881 
4,367 
5.0 
19 
11.5 
80 
Ifi 
486.7 
973 
1,461 
1,947 
2, 434 
2, 920 
3,407 
3,894 
4,381 
5.2 
20 
11.6 
82 
17 
488. 3 
976 
1,465 
1,953 
2,441 
2,930 
3,418 
3,906 
4,394 
5.4 
21 
11.7 
83 
18 
489.8 
980 
1,470 
1,959 
2,449 
2,939 
3,429 
3,919 
4,408 
.5.5 
22 
11.8 
84 
19 
491.3 
983 
1,475 
1,966 
2,457 
2,948 
3,440 
3,931 
4, 422 
5.7 
23 
11.9 
86 
20 
492. 9 
986 
1,479 
1,972 
2,465 
2,958 
3, 4.50 
3,943 
4,436 
5.8 
24 
12.0 
87 
21 
494.5 
989 
1,483 
1,978 
2,472 
2,967 
3,461 
3, 956 
4, 4.50 
6.0 
25 
12.1 
89 
22 
496.0 
992 
1,488 
1,984 
2, 480 
2, 976 
3, 472 
3,968 
4,464 
6.1 
26 
12.2 
90 
23 
497.6 
995 
1,493 
1,990 
2,488 
2,985 
3,483 
3,981 
4,478 
6.3 
27 
12.3 
91 
24 
499.1 
998 
1,498 
1,996 
2, 496 
2, 995 
3,494 
3,993 
4, 492 
6.4 
28 
12.4 
93 
25 
500. 7 
1,001 
1,502 
2, 003 
2, 503 
3,004 
3, 505 
4,005 
4, .506 
6.5 
29 
12. 5 
94 
26 
502. 2 . 
1,004 
1, 507 
2,009 
2, .511 
3, 013 
3, 515 
4,018 
4, 520 
6.7 
30 
12.6 
96 
27 
503.8 
1,007 
1,512 
2, 015 
2, 519 
3, 023 
3, 526 
4,030 
4,534 
6.8 
31 
12.7 
97 
28 
505. 3 
1,010 
1,516 
2,021 
2, 527 
3, 032 
3,537 
4,042 
4,548 
6.9 
32 
12.8 
99 
29 
506.9 
1,014 
1,521 
2,027 
2,534 
3,041 
3,548 
4,055 
4,562 
7.0 
33 
12.9 
100 
30 
508.4 
1,017 
1, 525 
2,034 
2, .542 
3, 050 
3,559 
4,067 
4,576 
7.2 
34 
13.0 
102 
31 
510.0 
1,020 
1,530 
2,040 
2, 550 
3, 060 
3,570 
4,080 
4,590 
7.3 
35 
13.1 
103 
32 
511. 5 
1,023 
1,535 
2, 046 
2, 558 
3, 069 
3,581 
4, 092 
4,604 
7.4 
36 
13.2 
105 
33 
513.0 
1,026 
1, 539 
2, 0,52 
2,565 
3,078 
3, 591 
4, 105 
4, 618 
7.5 
37 
13.3 
106 
34 
514.6 
1,029 
1,544 
2, 058 
2,573 
3,088 
3, 602 
4,117 
4,632 
7.6 
38 
13.4 
108 
35 
516. 2 
1,032 
1,549 
2, 065 
2, 581 
3,097 
3,613 
4, 129 
4, 645 
7.8 
39 
13.5 
109 
36 
517.7 
1,035 
1,553 
2,071 
2, 589 
3, 106 
3,624 
4, 142 
4, 659 
7.9 
40 
13.6 
111 
37 
519. 3 
1,039 
1,558 
2,077 
2, 596 
3,116 
3,635 
4,154 
4,673 
8.0 
41 
13.7 
112 
38 
520. 8 
1,042 
1,563 
2,083 
2,604 
3, 125 
3,646 
4,167 
4,687 
8.1 
42 
13.8 
114 
39 
522. 4 
1,045 
1,568 
2,089 
2,612 
3,134 
3,657 
4,179 
4,701 
8.2 
43 
13.9 
115 
40 " 
523. 9 
1,048 
1,572 
2, 095 
2,620 
3,144 
3,667 
4,191 
4,715 
8.3 
44 
14.0 
117 
41 
525. 5 
1,051 
1,576 
2,102 
2, 627 
3, 153 
3,678 
4,204 
4,729 
8.4 
45 
14.1 
119 
42 
527.0 
1, 054 
1, .581 
2, 108 
2, 635 
3,162 
3,689 
4, 216 
4,743 
8.5 
46 
14.2 
120 
43 
528.6 
1,057 
1, 586 
2,114 
2,643 
3,172 
3,700 
4, 229 
4,7,57 
8.6 
47 
14.3 
122 
44 
530. 1 
1,060 
1, 591 
2, 121 
2, 651 
3,181 
3,711 
4, 241 
4,771 
8.7 
48 
14.4 
124 
45 
531.7 
1,063 
1,595 
2, 127 
2, 658 
3,190 
3, 722 
4, 253 
4, 785 
8.8 
49 
14.5 
125 
46 
533.2 
1,066 
1,600 
2, 133 
2, 666 
3,199 
3,733 
4,266 
4,799 
8.9 
50 
14.6 
127 
47 
534.8 
1,070 
1,605 
2, 139 
2,674 
3, 209 
3,743 
4,278 
4, 813 
9.0 
51 
14.7 
129 
48 
536. 3 
1,073 
1,609 
2, 145 
2, 682 
3, 218 
3,754 
4,291 
4, 827 
9.1 
52 
14.8 
130 
49 
537.9 
1,076 
1,614 
2,154 
2,689 
3,227 
3,765 
4,303 
4,841 
9.2 
53 
14.9 
132 
50 
539.4 
1,079 
1,618 
2,158 
2,697 
3,237 
3,776 
4,315 
4,855 
9.3 
54 
1,5.0 
134 
51 
541.0 
1,082 
1,623 
2, 166 
2, 705 
3,246 
3,787 
4, 328 
4,869 
9.4 
55 
15.1 
135 
52 
542. 5 
1,085 
1,628 
2, 170 
2, 713 
3,255 
3,798 
4,340 
4,883 
9.5 
56 
15.2 
137 
53 
544.1 
1,088 
1,632 
2, 176 
2, 721 
3, 265 
3,809 
4, 353 
4,897 
9.6 
58 
1,5.3 
139 
54 
545. 6 
1,091 
1,637 
2, 183 
2,728 
3, 274 
3,819 
4, 365 
4,911 
9.7 
59 
15.4 
141 
55 
547. 2 
1,094 
1,642 
2,189 
2,736 
3,283 
3,830 
4,378 
4, 925 
9.8 
60 
15.5 
142 
56 
548. 7 
1,097 
1,646 
2, 195 
2,743 
3, 292 
3,841 
4,390 
4, 939 
9.9 
61 
15.6 
144 
57 
550.3 
1,101 
1,651 
2,201 
2, 752 
3, 302 
3, 852 
4, 402 
4,953 
10.0 
62 
1.5.7 
146 
58 
551.8 
1,104 
1,656 
■ 2, 207 
2,759 
3,311 
3,863 
4,415 
4,967 
10.1 
63 
15.8 
148 
59 
553.4 
1,107 
1,661 
2,214 
2,767 
3,320 
3,874 
4,427 
4,981 
1,5.9 
16.0 
1.50 
1,51 
60 
555.0 
1,110 
1,665 
2,220 
2,775 
3,330 
3, 885 
4,440 
4,995 
rt For all distances under 1.6 miles the correction may be taken as + 5 feet, 
is assumed 4.5 feet. 
Height of instrument 
