SURVEY OE THE EAST OF FRANCE. 
27 
(H. F .) 2 = ^ 2 ~3 sm u , where K, the moment of inertia of the magnet, is equal to 
/ 1 2 d 2 \ t 2 
W ( Yg + jg ) fa _^ , l, d, and r being distances. Hence, in order to transform the values 
of H. F. so that they may be expressed in the English units of a foot, a grain, and a 
second, we have only to multiply by the square root of the factor of mass, and to divide 
by the square root of the factor of distance, whose quotient is 2-1688. Effecting this 
transformation, and choosing for our coordinates the meridian of Paris, and a perpen- 
dicular to that meridian, the origin of coordinates being the Imperial Observatory, we 
obtain the equations of condition for determining the lines of equal Dip, Declination, 
and Intensity. As the second members of the equations are the same for the different 
elements, I will include in a single Table the first members of each set of equations, 
followed by the second members for the several stations. 
Table XXII. 
Station. 
Dip. 
Declination. 
H. F. 
T. F. 
Second members. 
Agen 
1-360 
2-252 
1-4441 
0-9111 
=z + 85-45#+319*30# 
Amiens 
2-938 
0-9639 
=3 + 0+4# — 72-80# 
Angers 
4-932 
3-272 
1-1450 
1-1637 
= 3+136-03# + 94-59# 
Angouleme 
3-652 
2-837 
1-3157 
1-0806 
= s+ 105-96# + 220-60// 
Arras 
6-387 
0-9474 
1-2661 
= z— 19-56#— 99-74;/ 
Bayonne 
2-113 
2-963 
1-4875 
0-9230 
= 0+ 192-46# + 369-46# 
Belfort 
0-195 
1-2389 
= c-210-34#+ 83-56# 
Bordeaux 
3-097 
3 003 
1-3730 
1-0101 
= 3 + 140-63# + 276-24# 
Brioude 
2-738 
1-365 
1-4072 
0-9605 
= 3— 51-17# + 244-23# 
Cette 
0-132 
1-5920 
= 0 _ 67 . 94 ^ 4 , 374 - 75 # 
Chateauroux 
4-115 
2-367 
1-2350 
1-0642 
= 3 + 29*84#+ 140-41# 
Clermont Ferrand 
3-202 
1-568 
1-3523 
1-0007 
= 3 — 36-24# + 21 1-62# 
Commerey 
1-1303 
= 3— 148-63#+ 4-93# 
Dijon 
3-917 
0-932 
1-2385 
0-9979 
=3-126-40#+ 103-60# 
Dunkirk 
6-938 
3-110 
0-8759 
1-3190 
=3- 0-91#— 151-31# 
F.pprnay 
5-593 
1-0752 
1-2583 
=2:_ 73-24#— 14-61# 
Eta nines 
5-267 
1-0960 
1-1769 
= z- 4- 7'9>5.t -f- 27*^9?/ 
Lamothe 
2-952 
1-3886 
0-9838 
= Z -L ] 64-77#+ 290-99// 
La Roche Chalais 
2-772 
1-3515 
= 3 + 1 15-00# + 255-01# 
La teste de Buch 
2-997 
3-065 
1-3857 
1-0035 
= 3 + 171-92# + 290-09# 
Le Mans 
5-217 
3-428 
1-0997 
1-1659 
= 3+100-28#+ 58-28# 
T.p Pay 
1-4402 
=z— 75-87#+26l-80# 
Limoges 
2-397 
1-3094 
= 3 + 52-50# + 207*38# 
Marseilles 
0-675 
0-068 
1-6332 
0-7649 
= 3— 154-40# + 382*63# 
Meaux 
5-403 
2-273 
1-0698 
1-1669 
=3— 24-84#— 7‘89# 
Mont de Marsan 
2-317 
2-672 
1-4584 
0-9283 
= 3 + 141*25# + 341 "73# 
Montelimart 
1-888 
0-592 
1-5003 
0-8749 
= 3-118-48# + 295-57# 
Montpellier 
1-255 
1-5788 
0-8355 
= 3 — 77-32# + 360-79// 
Moulins sur Allier 
3-723 
1-653 
1-2851 
1-0356 
=3- 46-84#+ 156-33# 
Nancy 
0-760 
1-1175 
= 3-175-17#+ 10*25# 
Nantes 
4-932 
3-963 
1-1415 
1-1552 
= 3+183-96#+ 113-74# 
Narbonne 
1-107 
1-018 
1-5944 
0-8207 
= 3 - 33-25#+ 390-25# 
Orange 
1-615 
0-462 
1-5395 
0-8692 
= 3- 122-62#+ 325+7# 
Orleans 
4-877 
2-423 
1-1379 
1-1244 
= 3+ 19’74#+ 64-52# 
Perigueux 
2-442 
1-3699 
= 3+ 79"! 8# + 253-90# 
Perpignan 
0-797 
0-987 
1-6319 
0-8009 
= 3 - 28-63# + 423-97# 
Poitiers 
4-138 
2-940 
1-2341 
1-0710 
= 3 + 94-86#+ 157*35# 
Sarrebourg 
0-243 
1-1183 
= 3-215-77#+ 7-18# 
Toulouse... 
1-768 
1-750 
1-5243 
0-8873 
=3+ 44-93#+ 360-98# 
Tournon 
2-303 
0-682 
1-4554 
0-9170 
= 3 — 122-53#+ 260-44# 
Tours 
4-738 
2-907 
1-1624 
1-1298 
= 3+ 77*41# + 100-29# 
Vesoul 
0-480 
1-2283 
= 3-177-88#+ 84-21# 
e 2 
