Gen. Roy’s Account of a propofed trigonometrical Operation. 
227 
Companion of the obferved length of 
CELESTIAL ARC 
Comprehended between the parallels of Greenwich and Perpignan. 
the celeftial arc ot the meridian, comprehended between the pa rallels of Greenwich and Perpignan, with the meafured and computed lengths of the correl'ponding terreftrial arc between thefe parallels. ' 
T i R R E S ' * “ 
Places of Obfervation. 
1 Perpignan — 
- Greenwich and M — 
f Point M near Dunkirk 
1 Perpignan - 
Point M and Paris 
f Paris Royal Obfervatory 
3 1 Perpignan — 
Paris and Bourges 
f Bourges — 
Perpignan — 
Bourges and Rodes * 
| Rodes — 
^ 1 Perpignan — 
Latitudes. 
0 
1- 
5 ' 
2840 
OO 
42 
4152 
00 
MP 
— 
5 ' 
I 
49 
8 
42 
4 ' 
52 
- 0 
48 
5 ° 
14 
00 
42 
4 ' 
52 
00 
47 
5 
4 
41 
42 
4 ' 
52 
oc 
44 
21 
'3 
36 
42 
4 1 
52 
00 
Differences of latitudes 
or celeltial arcs. 
Deg.Min.&c. 
8 
diff.c 
8 
diff. 
6 
diff. 1 
} 4 
diff. 2 
f Semi-diameter of the equator 
" Semi-axis between the poles - 
Ratio of the femi-diameters — 
Difference of the logarithms of the ratio 
Some r Equator — 
other J Degrees of the I 45th - m 
fillet rr* a ri/lion n. .u - I 440 
48 00 
I 
5 ° 5 2 
S 7 j 8 
35 ( 8 
22 00 
I 
919 
1241 
5 
2 1 '36 
I 
Dec. 
parts 
78 
4475 
332s 
93 
' 394 : 
7 S 2 S 
3869 
6309 
656 
R 
R C. 
Meafured 
Arc. 
Farhorps. 
chief 
proper 
ties. 
meridian at the] 66° 20' 
Pole — — 
Excefs of the degree of the meridian at the pole, 1 
above that at the equator - - J 
Degree, of Ion-/ , ~ 
giiude at rhe i 43 J*/ on ‘ h ° f France 
5 1 28 40 Greenwich - 
506499. 
' 334 ' 7 - 
373082. 
106564. 
266518. 
166009. 
100509. 
Computed arc on different hypothefes. 
Suppofing the earth to 
be a fphere. 
Fathoms. Error, 
Suppofing the Earth to be an oblate ellipfoid. 
534343 - 
27235- 
507108. 
I 33467 - 
37364 '- 
106658. 
2669S3. 
166200. 
100783. 
3486975 
3486975 
+ 609! + 
+ 5 ° 
+ 559 
+ 94 j, 
+ 465 
+ T 9 ' 
+ 274 j 
60484.^ 
60777.6 
61194.3 
60859.1 
60859.1 
60859.1 
60859.1 
00000.0 
44354-4 
60859.1 
44 ' 2'-3 
37904 2 
Error. 
+ 374-6 
+ 81.5 
- 335-2 
Fathoms. Error. 
535927 - 
2735 °- 
5 ° 8577 - 
' 33934 - 
374603. 
107007. 
267596. 
166620. 
100976. 
35°4545 
3484973 
179.047 to 
O.OO24323 
60484-5 
60993.4 
61342.3 
61509.3 
1024.8 
-233.1 
61165.8 
4446 1 . 2 
38225 9 
+ 2078] 
+ 5'7 
+ IJ 2 I 
+ 443 
+ 1078 
+ 420 
+ 467^ 
19572 
178 047 
Error. 
0.0 
+215.8 
+ 148.0 
-f- 106.8 
Fathoms. Error. 
535588 . 
2733 '- 
508257. 
'34038. 
374374 - 
106937. 
267437. 
166518. 
100919. 
3501802 
3483608 
>92.483 to 
0.0022622 
60484.5 
60957.7 
61281.9 
61437.' 
952.6 
61 1 17.9 
44430.4 
38181.3 
+ 17581 
+ 621 
+ 1292 
+ 373 <5 
+ 918 + 
+ 5°9 
+ 4 '°_ 
J ‘8194 
191.483 
Error. 
00 
+ 180.1 
+ 87.6 
+ 76.0 
Fathoms. Error, 
535088. 
27301. 
507787- 
' 33747 - 
374040 . 
106834. 
267206. 
166370. 
100836. 
3497814 
3481624 
216.06 to 
0.0020148 
60484.5. 
60905.9 
61194.3 
61332.2 
847.7 
61048.5 
44355-7 
38130.1 
+ 12881 
+ 33 ° 
+ 958 
+ 270 >■ 
+ 688 
+ 36' 
+ 327J 
j 16190 
215.0S 
Error. 
0.0 
+ 128.3 
0.0 
Fathoms. Error, 
534970 . 
27294. 
507676. 
' 337 ‘ 5 - 
37396 i. 
106810. 
267151. 
166334. 
100817. 
349 6 934 
3481221 
222.55 to 
0.0019558 
60484.5 
60893.5 
61173.4 
61308.4 
823.9 
61032.0 
44341.7 
38117.7 
+ " 77 l 
+ 298 
+ 879 
+ 246 }• i 
+ 633 + 
+ 325 
+ 308 
' 57 1 3 
221.55 
Error. 
+ II 5-9 
— 20 9 
— 12.7 
Fathoms. Error. 
533942 . 
27241. 
506701. 
' 33454 - 
373247 - 
106605. 
266642. 
166017. 
100625. 
3489949 
3474775 
230. to 229 
0.0018924 
60382.6 
60911.1 
44250.1 
37978.7 
2021 
37 
'55 
4 * V 3- 
124 
8 
1 16J 
' 5 1 74 
Error. 
— 101.9 
0.0 
- 146.5 
- 104.3 
Fathoms. Error. 
533860. 
27230/ 
506630. 
133412. 
373218. 
106582. 
266636. 
166005. 
100631. 
3487954 
3476718 
310.3 to 
0.001401s 
60484.5 
60777.6 
60977.7 
61073.0 
588.5 
60876.2 
44213.4 
37989-9 
+ '30 
- 5 
+ 136 
+ '8 I 
+ I l8 
- 4 
+ 122J 
• 11236 
309-3 
Error. 
0.0 
0.0 
— 216.6 
- 141.0 
Fathoms. Error. 
53375 1 • 
27206. 
506545- 
133360- 
373185- 
106555. 
266630. 
165991. 
100639. 
3485542 
3479087 
54° "> 539 
0.0008050 
60609 o 
60777.6 
60891.6 
60947.0 
338-0 
60834.1 
44141.9 
37932-4 
+ 461 
- 57 
+ '03 
- 9 
+ 1 12 
- 18 
+ 130 
} 6455 
Error. 
+ 12+5 
0.0 
+ 302.7 
- 212.5 
Suppofing the earth to he a fphcroid differing from 
the ellipfoid. 
More prominent in middle 
latitudes than the ellip- 
foid. 
Lefs prominent in middle 
latitudes than the ellipfoid 
of the fame femi-diameters. 
Fathoms. 
534997 - 
27296. 
507701. 
133722. 
373979 - 
106815. 
267164. 
166342. 
100822. 
349 6 934 
3481221 
222.55 to 
0.0019558 
60484.5 
60896.5 
61175.7 
61308.5 
824.0 
Error. 
+ I202I 
+ 3°5 
+ 897 
+ 251 7 
+ 646 
+ 333 
+ 3 ' 3 J 
Fathoms. 
533737 - 
27243. 
506494. 
' 33438 - 
373 ° 56 - 
106570. 
266486. 
165928. 
100558. 
' 57'3 
221.55. 
61033.0 
4434'. 8 
38117.2 
Error. 
0.0 
+ 118.9 
- 18.6 
— 12.6 
3496740 
3477210 
179.4 to 
0.0024274 
60484.5 
60740.0 
61203.7 
61506.6 
Error. 
~ s i 
+21 
—26 
+ 6>d 
- 3 2 
-81 
+ 49 J 
19530 
178.4 
Error. 
0.0 
—37-6 
+ 9-4 
61029.6 
44373-5 
38161.7 
+ 19-1 
H h 
Vol. LXXVII. 
Table 
