Gannett.! GEOGRAPHIC TABLES AND FORMULAS. 247 
Table 24. — For obtaining difference* of altitude for any minute, etc. — Continued. 
3°. 
Corrections 
for curva- 
1 
2 
3 
4 
8 
6 
7 
s 
9 
ture, refraction, and 
heightof instruments 

276.7 
553.4 
830 
1,107 
1,384 
1,660 
1, 937 
2, 214 
2,490 
Miles. 
Feet. 
1 
278.3 
556.5 
835 
1,113 
1,391 
1,670 
1,948 
2, 226 
2, 504 
10.1 
63 
2 
279.8 
559. 6 
839 
1,119 
1,399 
1,679 
1,959 
2, 238 
2, 518 
10.2 
64 
3 
281.3 
562. 7 
844 
1, 125 
1,407 
1,688 
1,969 
2, 251 
2, 532 
10.3 
65 
4 
282. 9 
565. 7 
849 
1,131 
1,414 
1,697 
1,980 
2,263 
2,546 
10.4 
67 
5 
284.4 
568. 8 
853 
1,138 
1,422 
1,706 
1, 991 
2, 275 
2, 560 
10.5 
68 
G 
286.0 
571.9 
858 
1,141 
1,430 
1,716 
2, 002 
2, 288 
2, 574 
10.6 
69 
7 
2B7. 5 
575. 
862 
1,150 
1,437 
1,725 
2, 012 
2, 300 
2, 587 
10.7 
70 
8 
289. 
578. 1 
867 
1,156 
1, 445 
1,734 
2, 023 
2, 312 
2,601 
10.8 
71 
9 
290. 6 
581.2 
872 
1, 162 
1,453 
1,743 
2,034 
2,325 
2,615 
10.9 
73 
10 
292. 1 
584.2 
876 
1,168 
1,461 
1,753 
2,045 
2,337 
2,629 
11.0 
75 
11 
293. 7 
587 3 
881 
1,175 
1,468 
1,762 
2, 056 
2, 349 
2,643 
11.2 
77 
12 
295.2 
590.4 
886 
1,181 
1,576 
1,771 
2,066 
2, 362 
2, 657 
11.4 
79 
13 
296.7 
593. 5 
890 
1,187 
1,484 
1,780 
2, 077 
2, 373 
2, 671 
11.6 
82 
14 
298. 3 
596. 6 
895 
1,193 
1,491 
1,790 
2,088 
2, 386 
2, 685 
11.8 
84 
15 
299. 8 
599. <', 
899 
1,199 
1,499 
1,799 
2, 099 
2, 399 
2, 698 
12.0 
87 
16 
301.4 
602. 7 
904 
1,205 
1, 507 
1,808 
2, 110 
2, 411 
2, 712 
12.2 
90 
17 
302. 9 
605. 8 
909 
1,212 
1,515 
1,817 
2, 120 
2, 423 
2, 726 
12.4 
93 
18 
304.4 
608. 9 
913 
1,218 
1, 522 
1,827 
2,131 
2, 436 
2,740 
12.6 
96 
19 
306.0 
612.0 
918 
1,224 
1,530 
1,836 
2,142 
2, 448 
2, 754 
12.8 
99 
20 
307. 5 
615. 
923 
1,230 
1,538 
1,845 
2,153 
2,460 
2,768 
13.0 
102 
21 
309.1 
618. 1 
927 
1,236 
1,545 
1,854 
2,163 
2. 173 
2, 782 
13.2 
105 
22 
310.6 
621. 2 
932 
1, 242 
1,553 
1,864 
2,174 
2, 485 
2,795 
13.4 
108 
23 
312. 1 
624. 3 
936 
1,249 
1, 561 
1,873 
2, 185 
2,497 
2,809 
13.6 
111 
24 
313. 7 
627. 4 
941 
1,255 
1,568 
1,882 
2, 196 
2, 510 
2,823 
13.8 
114 
25 
315. 2 
930. 5 
946 
1, 261 
1,576 
1,891 
2,207 
2, 522 
2,837 
14.0 
117 
26 
316. 8 
633. 5 
950 
1,267 
1,584 
1,901 
2, 217 
2,534 
2, 851 
14.2 
120 
27 
318. 3 
ii:;ti. ti 
955 
1 , 273 
1,592 
1,910 
2, 228 
2,547 
2,865 
14.4 
124 
28 
319.9 
639. 7 
960 
1,279 
1,599 
1,919 
2, 240 
2,559 
2,879 
14.6 
127 
29 
321. 4 
642. 7 
964 
1, 286 
1,607 
1,928 
2, 250 
2,571 
2,893 
14.8 
130 
30 
322. 9 
645. 9 
969 
1,292 
1,615 
1,938 
2,261 
2,584 
2,906 
15.0 
132 
31 
324. 5 
649. 
973 
1,298 
1,622 
1,947 
2,271 
2,596 
2, 920 
15.2 
137 
32 
326. 
652. 
978 
1,304 
1,630 
1,956 
2,282 
2, 608 
2,934 
15.4 
141 
33 
327. (i 
655. 1 
983 
1,310 
1,638 
1 , 965 
2, 293 
2, 621 
2, 948 
15.6 
• 144 
34 
329. 1 
658. 2 
987 
1,316 
1,646 
1,975 
2,304 
2,633 
2, 962 
15.8 
148 
35 
330. 6 
661.3 
992 
1,323 
1,653 
1,9X4 
2, 315 
2,645 
2, 976 
16.0 
151 
36 
332. 2 
664.4 
997 
1,329 
1,661 
1,993 
2, 325 
2, 658 
2,990 
16.2 
153 
37 
333.7 
667. 5 
1,001 
1,335 
1,669 
2, 002 
2, 336 
2, 670 
3,004 
16.4 
159 
38 
335. 3 
670. 5 
1, 006 
1,341 
1,676 
2, 012 
2, 347 
2, 682 
3,017 
16.6 
163 
39 
336. 8 
673. 6 
1,010 
1,347 
1,684 
2,021 
2,358 
2,695 
3,031 
16.S 
167 
40 
338.4 
676.7 
1,015 
1,353 
1,692 
2,030 
2, 369 
2,707 
3,045 
17.0 
170 
41 
339. 9 
(179. 8 
1,020 
1 , 360 
1,700 
2,039 
2,379 
2, 719 
3,059 
17.2 
174 
42 
341.4 
682. 9 
1,024 
1,366 
1,707 
2, 049 
2, 390 
2, 732 
3,073 
17.4 
178 
43 
343.0 
686. 
1,029 
1,372 
1,715 
2, 058 
2, 401 
2,744 
3,087 
17.6 
182 
44 
344. 5 
689. 1 
1 , 03 1 
1,37,H 
1,723 
2, 067 
2,412 
2, 756 
3,101 
17.8 
186 
45 
346. 1 
692. 1 
1 , 038 
1 , 38 1 
1,730 
2, 076 
2, 422 
2, 769 
3,115 
18.0 
190 
46 
347. 6 
695. 2 
1,043 
1,390 
1 , 738 
2, 086 
2, 433 
2, 781 
3, 129 
18.2 
195 
47 
349. 2 
698. 3 
1,047 
1,397 
1,746 
2, 095 
2,444 
2, 793 
3, 142 
18.4 
199 
48 
350. 7 
701.4 
1, 052 
1,403 
1,753 
2, 104 
2, 455 
2,806 
3, 156 
18.6 
203 
49 
352. 2 
704.5 
1,057 
1 , 409 
1,761 
2,113 
2, 166 
2,818 
3,170 
18.8 
207 
50 
353. 8 
707. 6 
1,061 
1,415 
1,769 
2, 123 
2, 476 
2,830 
3,184 
19.0 
212 
51 
355. 3 
710.7 
1,066 
1,421 
1,777 
2, 132 
2, 487 
2, 843 
3,198 
19.2 
216 
52 
356. 9 
713.7 
1,071 
1,427 
1,784 
2, 141 
2, 498 
2, 855 
3, 212 
19.4 
221 
53 
358. 1 
716.8 
1,075 
1,434 
1,792 
2, 150 
2, 509 
2, 867 
3, 226 
19.6 
225 
54 
360. 
719.9 
1,080 
1,440 
1,800 
2, 160 
2, 520 
2, 880 
3,240 
19.8 
230 
55 
361.5 
723. 
1, 085 
1,416 
1,807 
2, 169 
2, 530 
2, 892 
3, 253 
20.0 
234 
56 
363. 
726. 1 
1,089 
1,452 
1,815 
2, 178 
2, 541 
2, 904 
3,267 
21.0 
258 
57 
364.6 
729. 2 
1,094 
1,458 
1,823 
2,188 
2, 552 
2, 917 
3,281 
22.0 
282 
58 
366.1 
732. 3 
1,098 
1,465 
1,831 
2, 197 
2, 563 
2, 929 
3, 295 
23.0 
308 
59 
367.7 
735. 3 
1,103 
1,471 
1,838 
2,206 
2,574 
2,941 
3,309 
24.0 
335 
60 
369. 2 
738.4 
1, 108 
1,477 
1,846 
2,215 
2, 584 
2,954 
3,323 
25.0 
363 
nFor all distances under 1.6 miles the correction may be taken as +5 feet. 
is assumed 4.5 feet. 
Height of instrument 
