280 
GEOGRAPHIC TABLES AND FORMULAS. 
[BULL. 234. 
Table 26. — For ohkmmig differences of altitude for any 'minute, etc. — Continued. 
10° 
Corrections for 
-urva- 
1 
2 
3 
4 
5 
6 
7 
8 
ft 
ture 
. refraction 
and 
height of instrument.^i 

931.0 
1,862 
2,793 
3,724 
4,655 
5,586 
6,517 
7,448 
8,379 
1 
932. 6 
1,865 
2,798 
3,730 
4, 663 ■ 
5,596 
6,528 
7,461 
8,393 
Miles. 
Fed. 
Miles. 
Feet. 
2 
934.2 
1,868 
2,803 
3,737 
4,671 
5,605 
6,539 
7,473 
8,408 
1.6 
6 
10.2 
64 
3 
935. 8 
1,872 
2,807 
3,743 
4,679 
5,615 
6,550 
7,486 
8,422 
2.1 
7 
10.3 
65 
4 
937.4 
1,875 
2,812 
3,749 
4,687 
5,624 
6,661 
7,499 
8,436 
2.5 
8 
10.4 
67 
5 
938. 9 
1,878 
2,817 
3,756 
4,695 
5, 634 
6,573 
7,512 
8,450 
2.8 
9 
10.5 
68 
6 
940.5 
1,881 
2,822 
3, 762 
4,703 
5,643 
6,584 
7,524 
8,465 
3.1 
10 
10.6 
69 
7 
942.1 
1,884 
2, 826 
3,768 
4,711 
5,653 
6,595 
7,537 
8,479 
3.4 
11 
10.7 
70 
8 
943.7 
1,887 
2,831 
3,775 
4,718 
5,662 
6,606 
7, 550 
8,493 
3.6 
12 
10.8 
71 
9 
945.3 
1,891 
2,836 
3,781 
4,726 
5,672 
6,617 
7, 562 
8,'508 
3.8 
13 
10.9 
73 
10 
946.9 
1,894 
2,841 
3,787 
4,734 
5,681 
6, 628 
7, 575 
8,522 
4.1 
14 
11.0 
74 
11 
948.5 
1,897 
2,845 
3,794 
4,742 
5,691 
6,639 
7,588 
8,536 
4.3 
15 
11.1 
75 
12 
950.0 
1,900 
2,850 
3,800 
4, 750 
5,700 
6, 650 
7,600 
8, 550 
4.5 
16 
11.2 
77 
13 
951.6 
1,903 
2,855 
3,807 
4,758 
5, 710 
6, 661 
7,613 
8,565 
4.7 
17 
11.3 
78 
14 
953.2 
1,906 
2,860 
3,813 
4,766 
5,719 
6,672 
7,626 
8, 579 
4.8 
18 
11.4 
79 
15 
954.8 
1,910 
2,864 
3,819 
4,774 
5,729 
6,684 
7,638 
8, 593 
5.0 
19 
11.5 
80 
16 
956.4 
1,913 
2,869 
3,826 
4,782 
5,738 
6, 695 
7,651 
8,607 
5.2 
20 
11.6 
82 
17 
958.0 
1,916 
2,874 
3,832 
4,790 
5, 748 
6,706 
7,664 
8, 622 
5.4 
21 
11.7 
83 
18 
959. 6 
1,919 
2,879 
3,838 
4,798 
5, 757 
6,217 
7,676 
8,636 
5.5 
22 
11.8 
84 
19 
961.1 
1,922 
2,883 
3,845 
4,806 
5,767 
6,728 
7,689 
8,650 
5.7 
23 
11.9 
86 
20 
962.7 
1,926 
2,888 
3,851 
4,814 
5,776 
6,739 
7,702 
8, 665 
5.8 
24 
12.0 
87 
21 
964. 3 
1,929 
2,893 
3,857 
4,822 
5, 786 
6, 750 
7,715 
8,679 
6.0 
25 
12.1 
89 
22 
965.9 
1,932 
2,898 
3,864 
4,830 
5, 795 
6, 751 
7,727 
8,693 
6.1 
26 
12. 2 
90 
23 
967.5 
1,935 
2, 902 
3,870 
4,837 
5, 805 
6, 772 
7,740 
8,707 
6.3 
27 
12.3 
91 
24 
969.1 
1,938 
2,907 
3, 876 
4,845 
5,814 
6,784 
7, 753 
8,722 
6.4 
28 
12.4 
93 
25 
970.7 
1,941 
2,912 
3,883 
4,853 
5,824 
6, 795 
7, 765 
8,736 
6.5 
29 
12.5 
94 
26 
972. 2 
1,944 
2,917 
3,889 
4, 861 
5,833 
6,806 
7,778 
8,750 
6.7 
30 
12.6 
96 
27 
973.8 
1,948 
2,921 
3,895 
4,869 
5, 843 
6,817 
7,791 
8,764 
6.8 
31 
12.7 
97 
28 
975.4 
1,951 
2,926 
3,902 
4 877 
5,853 
6,828 
7,803 
8,779 
6.9 
32 
12.8 
99 
29 
977.0 
1,954 
2,931 
3,908 
4,885 
5,862 
6,839 
7,816 
8,793 
7.0 
33 
12.9 
100 
30 
978.6 
1,957 
2,936 
3,914 
4,893 
5,872 
6,850 
7,829 
8,807 
7.2 
34 
13.0 
102 
31 
980.2 
1,960 
2,941 
3,921 
4,901 
5, 881 
6,861 
7, 841 
8, 822 
7.3 
35 
13.1 
103 
32 
981.8 
1,964 
2, 945 
3,927 
4,909 
5,891 
6,872 
7,854 
8,836 
7.4 
36 
13.2 
105 
33 
983.4 
1,967 
2, 950 
3,933 
4,917 
5, 900 
6,884 
7,867 
8,850 
7.5 
37 
13.3 
106 
34 
985.0 
1,970 
2, 955 
3,940 
4,925 
5,910 
6, 895 
7,880 
8,865 
7.6 
38 
13.4 
108 
35 
986.5 
1,973 
2,960 
3,946 
4,933 
5, 919 
6,906 
7,892 
8,879 
7.8 
39 
13.5 
109 
36 
988.1 
1,976 
2,964 
3,953 
4,941 
5,929 
6,917 
7,905 
8,893 
7.9 
40 
13.6 
111 
37 
989.7 
1,980 
2,969 
3, 959 
4,949 
5, 938 
6,928 
7,918 
8,908 
8.0 
41 
13.7 
112 
38 
991. 3 
1,983 
2,974 
3,965 
4,957 
5, 948 
6, 939 
7,931 
8,922 
8.1 
42 
13.8 
114 
39 
992.9 
1,986 
2,979 
3, 972 
4,965 
5,957 
6,950 
7,943 
8,936 
8.2 
43 
13.9 
115 
40 
994.5 
1,989 
2,984 
3,978 
4,973 
5,967 
6,962 
7,956 
8,951 
8.3 
44 
14.0 
117 
41 
996.1 
1,992 
2,988 
3,984 
4,980 
5,977 
6,973 
7,969 
8,965 
8.4 
45 
14.1 
119 
42 
997.7 
1,995 
2,993 
3,991 
4,988 
5,986 
6,984 
7,981 
8,979 
8.5 
46 
14.2 
120 
43 
999.3 
1,999 
2, 998 
3,997 
4,996 
5,996 
6, 995 
7,994 
8,993 
8.6 
47 
14.4 
122 
44 
1, 000. 9 
2,002 
3,003 
4,003 
5,004 
6,005 
7,006 
8,007 
9,008 
8.7 
48 
14.3 
124 
45 
1,002.5 
2, 005 
8,007 
4,010 
5, 012 
6,015 
7,017 
8,020 
9,022 
8.8 
49 
14.5 
125 
46 
1, 004. 
2,008 
3,012 
4,016 
5,020 
6,024 
7,028 
8,032 
9,036 
8.9 
50 
14.6 
127 
47 
1,005.6 
2,011 
3,017 
4,023 
5,028 
6,034 
7,039 
8,045 
9,051 
9.0 
51 
14.7 
129 
48 
1,007.2 
2,014 
3,022 
4,029 
5, 036 
6, 043 
7,051 
8,058 
9,065 
9.1 
52 
14.8 
130 
49 
1, 008. 8 
2,018 
3,026 
4,035 
5,044 
6,053 
7,062 
8,071 
9,079 
9.2 
53 
14.9 
1.32 
50 
1,010.4 
2,021 
3,031 
4,042 
5,052 
6,062 
7,073 
8,083 
9,094 
9.3 
54 
15.0 
134 
51 
1,012.0 
2,024 
3,036 
4,048 
5, 060 
6,072 
7,084 
8,096 
9,108 
9.4 
55 
15.1 
135 
52 
1, 013. 6 
2,027 
3,041 
4,054 
5, 068 
6, 082 
7,095 
8,109 
9, 122 
9.5 
56 
15.2 
137 
53 
1,015.2 
2,030 
3,046 
4, 061 
5, 076 
6,091 
7,106 
8,121 
9,137 
9.6 
58 
15.3 
139 
54 
1,016.8 
2,034 
3,050 
4,067 
5,084 
6,101 
7,117 
8,134 
9,151 
9.7 
59 
15.4 
141 
55 
1,018.4 
2,037 
3, 055 
4,073 
5,092 
6,110 
7,129 
8,147 
9, 165 
9.8 
60 
15.5 
142 
56 
1,020.0 
2,040 
3,060 
4,080 
5, 100 
6,120 
7,140 
8,160 
9,180 
9.9 
61 
15.6 
144 
57 
1,021.5 
2,043 
3,065 
4,086 
5,108 
6,129 
7, 151 
8,172 
9,194 
10.0 
62 
15.7 
146 
58 
1,023.1 
2,046 
3,069 
4,093 
5,116 
6,139 
7,162 
8,185 
9,208 
10.1 
63 
15.8 
148 
59 
1,024.7 
2,049 
3,074 
4,099 
5,124 
6,148 
7,173 
8,198 
9,223 
15.9 
16.0 
150 
151 
60 
1,026.3 
2,053 
3,079 
4,105 
5,132 
6,158 
7,184 
8,211 
9,237 
a For all distances under 1.6 miles the correction may be taken as + 5 ieet. Height of instrument 
is assumed 4.5 feet. 
