332 Mr. Harvey’s experimental inquiries relative to the 
Trent, and which exhibits in a striking manner the difference 
between the observations at the starboard gangway, and at 
the binnacle, was observed on another occasion, when her 
head being in the same direction as the Helicon’s, the vari- 
ation at the former part of the vessel was 39 0 41' W, and at 
the latter 2i°4i' W. The variations and intensities are not 
however proportional. 
On another occasion, on board the Trent, the variation as 
determined on the starboard gangway, was found to agree 
with that determined at the binnacle. This observation, 
which would seem at first opposed to the remark before 
made, relative to a proportionality between the intensities at 
the binnacle and starboard gangway, and the variations de- 
termined at the same stations, may nevertheless be accounted 
for, from the sudden decline of the intensity, after passing 
the stations Gor^; since it is not improbable, but between 
the stations G, H, g\ A', points might have been found, 
at which the same intensity would have existed, as at the 
station 0. 
It was also remarked, that “ when Captain Kater’s com- 
“ pass (No. x.) was placed nearly a midships, and at a suffi- 
“ cient distance from the binnacle compasses to prevent at- 
“ traction, the variation was found to be 31 0 9' W ; and by a 
“ similar compass (No. 2.) on the ice, 25 0 28' W".” 
If now the station of the compass (No. 1. ) had been at S, 
the intensity at that point would have had nearly the same 
ratio to the intensity at © ( the intensity at the last mentioned 
point being 100.29, and the assumed terrestrial intensity 
100), as the former variation has to the latter. 
