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

369.2 
738 
1,108 
1,477 
1,846 
2,215 
2,584 
2, 95 1 
3,323 
1 
370.8 
742 
1,112 
1,483 
1,854 
2, 225 
2, 595 
2, 966 
3, 337 
Miles. 
Feet. 
Miles. 
Feet. 
2 
372. 3 
745 
1,117 
1,489 
1,862 
2,234 
2, 606 
2, 978 
3,351 
1.6 
6 
10. 2 
64 
3 
373.8 
748 
1,122 
1,495 
1,869 
2,243 
2, 617 
2, 991 
3, 365 
2.1 
7 
10.3 
65 
4 
375.4 
751 
1,126 
1,502 
1,877 
2, 252 
2, 628 
3,003 
3, 87S 
2.5 
8 
10.4 
67 
5 
376. 9 
754 
1,131 
1,508 
1,885 
2, 262 
2, 639 
3, 015 
3, 392 
2.8 
9 
10.5 
68 
G 
378.5 
757 
1,135 
1,514 
1,892 
2,271 
2, 649 
3,028 
3,406 
3.1 
10 
10. G 
G9 
7 
380.0 
760 
1,140 
1,520 
1,900 
2,280 
2,660 
3, 040 
3,420 
3.4 
11 
10.7 
70 
8 
381.6 
763 
1,145 
1,526 
1,908 
2,289 
2,ii71 
3, 0.% 
3,434 
3.6 
12 
10.8 
71 
9 
383.1 
766 
1,149 
1,532 
1,916 
2,299 
2,682 
3, 0(15 
3,448 
3.8 
13 
10. 9 
73 
10 
384.7 
769 
1,154 
1,539 
1,923 
2,308 
2, 693 
3,077 
3,462 
4.1 
14 
11.0 
74 
11 
386. 2 
772 
1,159 
1, 545 
1,931 
2,317 
2, 703 
3,090 
3,476 
4.3 
15 
11.1 
75 
12 
387. 7 
77.", 
1,163 
1,551 
1,939 
2, 326 
2,714 
3, 102 
3, 490 
4.5 
16 
11.2 
/ / 
13 
389.3 
779 
1,168 
1 , 557 
1,946 
2,336 
2, 725 
3,114 
3,504 
4.7 
17 
11.3 
78 
14 
390.8 
782 
1,172 
1,563 
1,954 
2, 345 
2, 736 
3,127 
3,517 
4.8 
18 
11.4 
79 
15 
392. 4 
785 
1,177 
1,569 
1,962 
2, 354 
2.717 
3, 139 
3, 531 
5.0 
19 
11.5 
80 
16 
393.9 
7ns 
1,182 
1,576 
1,970 
2, 363 
2. 757 
3,151 
3.515 
5. L» 
20 
11. G 
82 
17 
395.5 
791 
1,186 
1 . 582 
1,977 
2, 373 
2,768 
3,164 
8. 55'.) 
5.4 
21 
11.7 
83 
18 
397.0 
794 
1,191 
1,588 
1,985 
2,382 
2. 77'.) 
3,176 
8, 57:; 
5. 5 
22 
11.8 
si 
19 
398. 6 
797 
1.196 
1 , 594 
1,993 
2,391 
2,790 
:;, iss 
8, 587 
5.7 
23 
11.9 
SG 
20 
400.1 
800 
1,200 
1,600 
2,000 
2,401 
2,801 
3,201 
3, 601 
5.8 
24 
12.0 
87 
21 
401.6 
803 
1,205 
1,607 
■_'. Hits 
2,410 
2,811 
3,213 
3,615 
6.0 
25 
12.1 
89 
22 
403. 2 
806 
1,210 
1,613 
2, on; 
2,419 
2, 822 
3, 22.") 
3, 629 
6.1 
26 
12.2 
90 
23 
404.7 
809 
1,214 
1,619 
2,024 
2, 428 
2, 833 
3,238 
8. in:; 
6. 8 
27 
12.3 
91 
24 
406. 3 
813 
1,219 
L,625 
2,031 
2,438 
2,844 
3, 250 
3,656 
6. 4 
28 
12.4 
93 
25 
407.8 
816 
1 . 228 
1,631 
2,039 
2,447 
2. 855 
3. 263 
3,670 
6. 5 
29 
12.5 
94 
26 
409.4 
819 
1 . 228 
1,637 
2.1)17 
2, 456 
2,866 
.",, 275 
8, (181 
C>. 7 
30 
12.6 
96 
27 
410.9 
822 
1,233 
1,644 
2,055 
2, 165 
2,876 
:;,js7 
3,698 
6.8 
31 
12.7 
97 
28 
U2.5 
825 
L.237 
1,650 
2,062 
2, 475 
2. 887 
3,300 
8,712 
c. 9 
32 
12.8 
99 
29 
414.0 
828 
1 . 242 
1,656 
2, 070 
•J. isi 
2,898 
3,312 
:;. 726 
7.0 
33 
12.9 
100 
30 
415.5 
331 
1,247 
1,662 
2,078 
2,498 
2,909 
3,324 
8,740 
7.2 
34 
13.0 
102 
31 
117.1 
834 
1,251 
1,668 
'J.I is;, 
2,503 
2. 921) 
3,337 
8,751 
7.3 
85 
13.1 
108 
32 
418.6 
s;;7 
1,256 
1,675 
2, 093 
•2,r»i2 
2,930 
3,349 
8, 768 
7.4 
36 
13.2 
105 
33 
420.2 
840 
1,261 
1,681 
L'.llil 
2,521 
2, 941 
3,361 
8, 782 
7.5 
37 
13.3 
106 
34 
121.7 
843 
1,265 
1,687 
2,109 
2, 530 
2, 952 
8,371 
8. 796 
7.6 
38 
13. 1 
108 
35 
428. 3 
847 
1,270 
1,693 
2,116 
2, 540 
2, 963 
8, 386 
3,809 
7.8 
39 
13.5 
109 
36 
424.8 
850 
1 , 27 1 
1, 699 
2,121 
2,549 
2, 974 
3,399 
3,823 
7.9 
40 
13. G 
111 
37 
426. 4 
853 
1 , 279 
1,705 
2, 132 
2, 558 
2,985 
8, 111 
3, 837 
8.0 
41 
13.7 
112 
38 
127.9 
856 
1 , 28 1 
1,712 
2,140 
2,567 
2, 995 
8. 128 
8, 851 
8.1 
42 
13. S 
114 
39 
429.5 
859 
L.288 
1,718 
2,147 
2, 577 
3,006 
8,, 136 
3,865 
8.2 
43 
13. 9 
115 
40 
131.0 
862 
1,293 
1,724 
2, 155 
2.586 
3,017 
3,448 
3,879 
8.3 
44 
14.0 
117 
11 
132. .") 
865 
1,298 
1,730 
2,163 
2, 595 
3,028 
3, 460 
3, 893 
8.4 
45 
14.1 
119 
42 
434. 1 
868 
1,302 
1,736 
2, 170 
2, 605 
3, 039 
3,473 
3,907 
8.5 
46 
14.2 
120 
43 
435.6 
871 
1,307 
1,743 
2,178 
2, 614 
3,049 
3, 485 
3, 921 
8.6 
47 
14.3 
122 
44 
437. 2 
874 
1,312 
1,749 
2,186 
2,623 
3,060 
3, 498 
3, 935 
8.7 
48 
14.4 
121 
45 
188. 7 
877 
1,316 
1, 755 
2, 194 
2, 632 
3,071 
3, 510 
3, 949 
8.8 
49 
14.5 
125 
40 
440.3 
881 
1,321 
1,761 
2,201 
2, 642 
3, 082 
3,522 
8, 963 
8.9 
50 
14. G 
127 
47 
441.8 
884 
1,325 
1,767 
2,209 
2,651 
3,093 
3, 535 
3, 976 
9.0 
51 
14.7 
129 
is 
443.4 
887 
1,330 
1,773 
2,217 
2, 660 
3,104 
3, 547 
3,990 
9.1 
52 
14.8 
130 
49 
444. 9 
890 
1,335 
1,780 
2, 225 
2,669 
3,113 
3,558 
4,003 
9.2 
53 
14.9 
1 32 
50 
446.5 
893 
1,339 
1,786 
2,232 
2,679 
3,125 
3,572 
4,018 
9.3 
54 
15.0 
134 
51 
448.0 
896 
1 , 344 
1,792 
2, 240 
2,688 
3, 136 
3,584 
4, 032 
9.4 
55 
15.1 
135 
52 
449. 6 
899 
1,349 
1,798 
2,248 
2,697 
3,147 
3,596 
4,046 
9.5 
56 
15.2 
137 
53 
451.1 
902 
1,353 
1,804 
2, 256 
2, 707 
3,158 
3, CO 1 .) 
4,060 
9.6 
58 
15.8 
139 
54 
452. 7 
905 
1,358 
1,811 
2, 263 
2,716 
3,169 
3,621 
4,074 
9.7 
59 
15.4 
141 
55 
454. 2 
908 
1,363 
1,817 
2, 271 
2, 725 
3,179 
3, 634 
4,088 
9.8 
GO 
15.5 
142 
56 
455.8 
912 
1,367 
1,823 
2, 279 
2,735 
3,190 
3,646 
4, 102 
9.9 
61 
15.6 
144 
57 
457. 3 
915 
1,372 
1,829 
2,286 
2, 744 
3,201 
3,658 
4,116 
10.0 
62 
15.7 
146 
58 
458.8 
918 
1,377 
1,835 
2, 294 
2,753 
3,212 
3, 671 
4,130 
10.1 
63 
15.8 
148 
59 
460.4 
921 
1,381 
1, 842 
2,302 
2,762 
3,223 
3,683 
4,144 
15.9 
1G.0 
150 
151 
60 
461.9 
924 
1,386 
1,848 
2,310 
2,772 
3,234 
3,696 
4,157 
a For all distances under 1.6 miles the correction may be taken as + 5 feet, 
is assumed 4.5 feet. 
Height of instrument 
