THE RIVER THAMES AT LONDON BRIDGE AND THE SEA. 
J97 
A Table of the Curvature of the Earth, the mean diameter being- 41,807,803 feet. 
Dist. 
Curvature. 
Dist. 
Curvature. 
Dist. 
Curvature. 
Dist. 
Curvature. 
1 Dist. 
Curvature. 
I 
Dist. 
Curvature. 
Feet. 
Feet. 
Feet. 
Feet. 
Feet. 
; Feet. 
60 
000086 
220 
001157 
380 
003453 
540 
006975 
700 
011721 
860 
017691 
65 
000101 
225 
001216 
385 
003544 
545 
007104 
705 
011888 
865 
017897 
70 
000117 
230 
001265 
390 
0036.37 
550 
007235 
710 
012057 
870 
018104 
75 
000134 
235 
001321 
395 
003730 
555 
007368 
715 
012228 
875 
018313 
80 
000153 
240 
001378 
400 
003827 
560 
007501 
720 
012399 
880 
018523 
85 
000173 
245 
001435 
405 
003923 
565 
007636 
725 
012572 
885 
018734 
90 
000194 
250 
001495 
410 
004021 
570 
007771 
730 
012746 
890 
018946 
95 
000216 
255 
001555 
415 
004119 
575 
007908 
735 
012921 
895 
019159 
100 
000239 
260 
001617 
420 
004219 
580 
008046 
740 
013098 
900 
019379 
105 
000264 
265 
001680 
425 
004321 
585 
008186 
745 
013275 
905 
019591 
110 
000290 
270 
001744 
430 
004422 
590 
008326 
750 
013454 
910 
019807 
115 
000316 
275 
001809 
435 
004526 
595 
008468 
755 
013634 
915 
020025 
120 
000344 
280 
001875 
440 
004621 
600 
008611 
760 
013816 
920 
020245 
125 
000374 
285 
001943 
445 
004735 
605 
008755 
765 
013998 
925 
020466 
130 
000404 
290 
002016 
450 
004843 
610 
008901 
770 
014181 
930 
020687 
135 
000436 
295 
002082 
455 
004952 
615 
009047 
775 
014366 
935 
020911 
140 
000469 
300 
002152 
460 
005060 
620 
009195 
780 
014552 
940 
021135 
145 
000503 
305 
002224 
465 
005171 
625 
009344 
785 
014740 
945 
021360 
150 
000538 
310 
002298 
470 
005284 
630 
009494 
790 
014928 
950 
021586 
155 
000575 
315 
002373 
475 
005397 
635 
009645 
795 
015118 
955 
021824 
160 
000612 
320 
002449 
480 
005511 
640 
009798 
800 
015308 
960 
022043 
165 
000651 
325 
002526 
485 
005626 
645 
009951 
805 
015500 
965 
022274 
170 
000691 
330 
002605 
490 
005743 
650 
010105 
810 
015693 
970 
022505 
175 
000732 
335 
002684 
495 
005861 
655 
010262 
815 
015888 
975 
022738 
180 
000/75 
340 
002764 
500 
005978 
660 
010419 
820 
016083 
980 
022972 
185 
000818 
345 
002847 
505 
006100 
665 
010577 
825 
016280 
985 
023207 
190 
000863 
350 
002929 
510 
006221 
670 
010737 
830 
016478 
990 
023443 
195 
000909 
355 
003014 
515 
006324 
675 
010898 
835 
016677 
995 
023681 
200 
000957 
360 
003100 
520 
006467 
680 
011061 
840 
016877 
1000 
023919 
205 
001005 
365 
003187 
525 
006593 
685 
011223 
845 
017079 
210 
001054 
370 
003275 
530 
006719 
690 
011383 
850 
017281 
215 
001105 
375 
003363 
535 
006846 
695 
011554 
855 
017485 
Note. — I received the following rule for curvature and refraction together, 
from Davies Gilbert, Esq., and it will be found useful in ascertaining 
heights approximately. 
Rule . — Assume the diameter of the earth as 10,000 instead of 
7918 miles, and which will give the refraction about one- 
tenth the intercepted arc. 
