276 GEOGRAPHIC TABLES AND FORMULAS. [bull. 234. 
Table 26. — For obtaining differences of altitude for any minute, etc — Continued. 
6" 
Corrections for 
3urva- 
1 
2 
3 
4 
5 
(> 
7 
8 
9 
ture, refraction and 
height of instrument.a 

555. 
1,110 
1,665 
2,220 
2, 775 
3,330 
3,885 
4,440 
4, 995 
1 
556. 5 
1,113 
1,670 
2,226 
2,783 
3,339 
3,896 
4,452 
5,009 
Miloi. 
Feci. 
Miles. 
Feet. 
2 
558.1 
1,116 
1,674 
2, 232 
2,790 
3,348 
3,906 
4,464 
5,023 
1.6 
6 
10.2 
64 
3 
559.6 
1,119 
1,679 
2,238 
2,798 
3, 358 
3,917 
4,477 
5,037 
2.1 
7 
10.3 
65 
4 
561.2 
1, 122 
1,684 
2, 245 
2, 806 
3,367 
3, 928 
4,489 
5,050 
2.5 
8 
10.4 
67 
5 
562. 7 
1,125 
1,688 
2, 251 
2, 814 
3,376 
3,939 
4, 502 
5,064 
2.8 
9 
10.5 
68 
6 
564.3 
1,129 
1,693 
2, 257 
2,821 
3,386 
3,950 
4,514 
5,078 
3.1 
10 
10.6 
69 
7 
565. 8 
1,132 
1,697 
2,263 
2,829 
3,395 
3,961 
4,527 
5,092 
3.4 
11 
10.7 
70 
8 
567.4 
1,135 
1, 702 
2,270 
2,837 
3,404 
3,972 
4,539 
5,106 
3.6 
12 
10.8 
71 
9 
568.9 
1,138 
1,707 
2,276 
2,845 
3,414 
3,983 
4,551 
5,120 
3.8 
13 
10.9 
73 
10 
570. 5 
1.141 
1,711 
2, 282 
2,852 
3, 423 
3,993 
4, 564 
5, 134 
4.1 
14 
11.0 
74 
11 
572. 
1,144 
1,716 
2,288 
2, 860 
3, 432 
4,004 
4, 576 
5,148 
4.3 
15 
11.1 
75 
12 
573.6 
1,147 
1,721 
2,294 
2, 868 
3, 442 
4,015 
4,589 
5,162 
4.5 
16 
11.2 
Ti 
13 
575.2 
1,150 
1,725 
2,301 
2, 876 
3,451 
4,026 
4,601 
5,176 
4.7 
17 
11.3 
78 
14 
576. 7 
1,153 
1,730 
2,307 
2,884 
3,460 
4,037 
4,614 
5,190 
4.8 
18 
11.4 
79 
15 
578.3 
1,157 
1, 735 
2,313 
2, 891 
3,470 
4,048 
4, 626 
5,204 
5.0 
19 
11.5 
80 
16 
579.8 
1,160 
1,739 
2,319 
2, 899 
3,479 
4, 059 
4,639 
5, 218 
5.2 
20 
11.6 
82 
17 
681.4 
1,163 
1,744 
2,325 
2,907 
3,488 
4,070 
4,651 
5, 232 
5.4 
21 
11.7 
83 
18 
582.9 
1,166 
1,749 
2, 332 
2,915 
3,498 
4,080 
4,663 
5,246 
5.5 
22 
11.8 
84 
19 
584. 5 
1,169 
1,753 
2,338 
2, 922 
3,507 
4,091 
4,676 
5,260 
5.7 
23 
11.9 
86 
; 20 
586.0 
1,172 
1,758 
2,344 
2,930 
3, 516 
4,102 
4,688 
5, 274 
5.8 
24 
12.0 
87 
21 
587.6 
1,175 
1,763 
2,350 
2,938 
3, 526 
4,113 
4,701 
5,288 
6.0 
25 
12.1 
89 
■ 22 
589.1 
1,178 
1,767 
2,357 
2,946 
3, 535 
4,124 
4,713 
5, 302 
6.1 
26 
12.2 
90 
] 23 
690.7 
1,181 
1,772 
2,363 
2, 953 
3,544 
4,135 
4,726 
5,316 
6.3 
27 
12.3 
91 
24 
592. 2 
1,185 
1,777 
2,369 
2,961 
3,554 
4,146 
4,738 
5,330 
6.4 
28 
12.4 
93 
25 
593.8 
1,188 
1,781 
2, 375 
2,969 
3,563 
4,157 
4,750 
5,344 
6.5 
29 
12.5 
94 
26 
59,5.4 
1,191 
1,786 
2,381 
2, 977 
3, 572 
4,168 
4,763 
5,358 
6.7 
30 
12.6 
96 
27 
596.9 
1,194 
1,791 
2,388 
2,985 
3, 581 
4,178 
4,775 
5, 372 
6.8 
31 
12.7 
97 
: 28 
598.5 
1,197 
1,795 
2,394 
2,992 
3, 591 
4,189 
4,788 
5,386 
6.9 
32 
12.8 
99 
! 29 
600.0 
1,200 
1,800 
2, 400 
3,000 
3,600 
4,200 
4,800 
5,400 
7.0 
33 
12.9 
100 
: 30 
601.6 
1,203 
1,805 
2,406 
3,008 
3,609 
4,211 
4,813 
5, 414 
7 2 
34 
13.0 
102 
: 31 
603.1 
1,206 
1,809 
2,413 
3,016 
3,619 
4,222 
4,825 
5,428 
I'.Z 
35 
13.1 
103 
' 32 
604.7 
1,209 
1,814 
2,419 
3,023 
3, 628 
4,233 
4,838 
5,442 
7.4 
36 
13.2 
105 
33 
606.3 
1,213 
1,819 
2,425 
3, 031 
3,637 
4, 244 
4,850 
5,456 
7.5 
37 
13.3 
106 
' 34 
607. 8 
1 , 216 
1,823 
2, 431 
3, 039 
3,647 
4, 255 
4,862 
5,470 
7.6 
38 
13.4 
108 
35 
609. 4 
1,219 
1,828 
2,437 
3,047 
3, 656 
4,266 
4, 875 
5,484 
7.8 
39 
13.5 
109 
36 
610.9 
1, 222 
1,833 
2,444 
3, 055 
3, 666 
4,276 
4,887 
5,498 
7.9 
40 
13.6 
111 
37 
612.5 
1,225 
1,837 
2,450 
3,062 
3, 675 
4, 287 
4,900 
5, 512 
8.0 
41 
13.7 
112 
38 
614.0 
1,228 
1,842 
2,456 
3,070 
3,684 
4,298 
4,912 
5,526 
8.1 
42 
13.8 
114 
39 
615.5 
1,231 
1,847 
2,462 
3,078 
3,694 
4,309 
4,925 
5,540 
8.2 
43 
13.9 
115 
40 
617.2 
1,234 
1,851 
2,469 
3,086 
3,703 
4,320 
4,937 
5,554 
8.3 
44 
14.0 
117 
41 
618.7 
1,237 
1,856 
2,475 
3,094 
3,712 
4,331 
4, 950 
5,568 
8.4 
45 
14.1 
119 
42 
620.3 
1,241 
1,861 
2,481 
3,101 
3,722 
4,342 
4, 962 
5, 582 
8.5 
46 
14.2 
120 
43 
621.8 
1,244 
1,865 
2,487 
3,109 
3,731 
4,353 
4,975 
5, 596 
8.6 
47 
14.3 
122 
44 
623. 4 
1,247 
1,870 
2,494 
3,117 
3,740 
4,364 
4,987 
5, 610 
8.7 
48 
14.4 
124 
45- 
624.9 
1,250 
1,875 
2,500 
3, 125 
3,750 
4,374 
4,999 
5,624 
8.8 
49 
14.5 
125 
46 
626.5 
1,253 
1,879 
2,506 
3,132 
3,759 
4,385 
5,012 
5,638 
8.9 
50 
14.6 
127 
47 
628.0 
1,256 
1,884 
2, 512 
3,140 
3,768 
4,396 
5,024 
5,653 
9.0 
51 
14.7 
129 
48 
629.6 
1,259 
1,889 
2,518 
3,148 
3,778 
4,407 
5,037 
5,667 
9.1 
52 
14.8 
130 
49 
631.2 
1,262 
1,894 
2, 525 
3,156 
3,787 
4,418 
5,049 
5,681 
9.2 
53 
14.9 
132 
50 
632.7 
1,265 
1,898 
2,531 
3,164 
3,796 
4,429 
5, 062 
5,695 
9.3 
54 
15.0 
134 
51 
634.3 
1,269 
1,903 
2, 537 
3,171 
3,806 
4,440 
5, 074 
5,709 
9.4 
55 
15.1 
135 
52 
635.8 
1,272 
1,908 
2,543 
3,179 
3,815 
4,451 
5,087 
5, 723 
9.5 
56 
15.2 
137 
53 
637.4 
1,275 
1, 912 
2,550 
3,187 
3,824 
4,462 
5,099 
5, 737 
9.6 
58 
15.3 
139 
54 
638.9 
1,278 
1,917 
2, 556 
3,195 
3,834 
4,473 
5, 112 
5,751 
9.7 
59 
15.4 
141 
55 
640. 5 
1, 281 
1, 922 
2,562 
3,203 
3,843 
4,484 
5,124 
5,765 
9.8 
60 
15.5 
142 
56 
642. 1 
1,284 
1,926 
2,568 
3, 210 
3, 852 
4,494 
5, 136 
5,779 
9.9 
61 
15.6 
144 
67 
643.6 
1,287 
1,931 
2,575 
3,218 
3,862 
4,505 
5,149 
5,793 
10.0 
62 
15.7 
146 
58 
645.2 
1,290 
1,936 
2,581 
3,226 
3,871 
4,516 
5, 161 
5,807 
10.1 
(;3 
15.8 
148 
59 
646.7 
1,293 
1,940 
2,587 
3,234 
3,880 
4, 527 
5,174 
5,821 
15.9 
16.0 
150 
151 
60 
648.3 
1,297 
1, 945 
2,593 3,242 
3,890 
4,538 
5,186 
5,835 
a For all distances under 1.6 miles the correction may be taken as + 5 feet. 
) assumed 4.6 feet. 
Height of instrument 
