LIEUT. -COLONEL SABINE ON TERRESTRIAL MAGNETISM. 
\3 
For the first series we have London as the primary station, where I = \,v — 44° 06', 
and w — 3‘7/3 ; whence at other stations 
I' = * 1 845 w' cosec v', 
w' being - taken from Table A ; and for the second series the Cape as the primary 
station, where I = 0 - 715, v = 51° 10', and w = 3 - 032 ; whence at other stations 
I' = • 1 837 w' cosec v', 
w' being taken from Table B. 
Table I. contains the observations made with the weights and deflectors on shore 
and on board the Erebus, between London and the Cape of Good Hope. Of 647 
observations comprised in this Table, I have only found it necessary to consider 
a single one as doubtful, namely, the second observation with the constant weight of 
one grain at the Cape of Good Hope ; its result differs so much from that of the ob- 
servation on the preceding day with the same weight, and with those of the prece- 
ding and of the same day with the weight of 1^ grain, that I have thdught it safer to 
omit it in taking the mean of the results at that station ; but the observation itself, 
and its result, are both given in the Table. 
