92 
LIEUT.-COLONEL SABINE ON TERRESTRIAL MAGNETISM. 
5.5. E. 1 
— -909c— 2’85d= -2-876; 
5.5. W. J 
S. —l-000t’-2-85d= — 2-843. 
Changing’ the signs of the three last equations, and summing, we have 
5-24c=+-071 ; 
whence c=+’014. 
To obtain c from the observations of inclination and intensity alone, we have at 
N. "331c — '9id — — “941 ; 
N.N.E.l 
N.N.W.J 
•309c— -94d— — -942 
N.E. i 
N.W. j' •a220-'94rf=-'9-13; 
S.E. "j 
S.W. J 
218c— -94c/= --948 ; 
S.S.E. 1 7 
s.s.w.!- 301c - 94fc - 948; 
S. — '331c — -94d= — •947- 
Changing the signs of the three last equations, and summing, d is eliminated as 
before, and 
c=±^7=+-01°. 
From the observations at Port Louis, we have the following values to be employed 
in the equations : 
N. £'=0; £ = 0; d = — 52° 50' ; ^=1*279 ; 
NNw}^ = 22 ° 3 ° ,; 22 ° 01 '’ 0' = — 52° 42'; p'=P290; 
J^= 45° O'; £= 43° 58'; O’ =-52° 45'; <p' = 1*290; 
j^'= 135° O'; ^=133°03'; O’— — 51° 59'; <p'=l'323. 
cf w k'=157° 30'; £=155° 52'; — 51°33' ; <p'= 1*330. 
o.o. W . J 
S. £' = 0; £=0; &— -51° 43' ; p'=P346. 
6= — 52° 05' ; <p=V 32. 
Substituting these values in equation (11.), we obtain 
+ *094 
5-24 
= +•018: 
or from the observations of inclination and intensity alone, 
+ •051 
c— 
3-22 
