MAGNETIC INCLINATION AT GOTTINGEN. 643 
sin (f+ c).sin (A + c) sin (f +c). sin(g — ec) ah 
sin (g +h). sin(f+)° sn (kh —f).sm(h+g)° 
The same formula applies for dc! if we only substitute f, g, h, 
for f', g', h'. Applied to our calculation they give 
dc = — 3°435 df + 3°441 dg + 5876 dh 
dd = — 3-499 df! + 3°494 dg! + 5:993 dil. 
Remembering that the values of / and 1! themselves are still less 
trustworthy, and may therefore contain errors of one or two 
minutes, it is evident that the values found for c and c! merit no 
confidence. 
For the sake of completeness, I subjoin the mode of finding 
the remaining unknown quantities. 
From the combination of equations (1.) and (2.), it follows that 
4g . sin(f+g) sin (Q—c), (7.) 
m Bin (2 e)-F Fg) 2 
and thus, under the application of equation (3.), 
sin (2c + f—g) cos (Q + h) 
sin (f+ 9) . cos (h +c) sin (Q—c)’ 
In an entirely similar manner equations (4—6.) give 
sin (2c! + f' — g') cos (Q + h’) 
sin (f! + g') . cos (A' + c') * sin (Q — c) 
Consequently if, for the sake of brevity, we write 
sin (2c! + f! — g') . sin (f+ g) . cos (h + ©) _f 
sin (2e+ f—g).sin(f’+g').cos() +c) ” 
then 
cos (Q + A) . sin (Q— ec’) =k cos (Q + A’). sin (Q— Cc). 
If we make 
cos (hk — c) —k cos (#' —c) => Asn B 
sin (hk — c'!) — k sin (h' — c) = A cosB 
sin (k + ce) —k sin (A! + ©) C 
1, a ear 7 
G+ 
cos? = — 
tani = 
tan 2 = 
this equation takes the simple form 
cos (2Q — B) =C, 
whereby Q is determined; i is then found from one of the two 
equations for tani; and lastly, +, & are found from (1.) or 
(2.), and from (4.) or (5.). Respecting these calculations we may 
conclude with the following remarks :-— 
I. In order to be able to conduct with precision the numerical 
