316 Mr. Harvey's experimental inquiries relative to the 
the least when her head was north ; and in the starboard 
section of the lower deck when it was north-west. 
Of the column devoted to the mean of the intensities of the 
three sections, it may be observed, that on the poop, fore- 
castle, and upper deck, the mean results were the least when 
her head bore east ; and on the lower deck, when it was 
north. The maximum result was also found on the poop, 
when her head was north ; and on the forecastle, upper, and 
lower decks, when north-west. It may also be remarked, 
that the mean of the intensities of the three sections on the 
upper and lower decks were all below the assumed terres- 
trial intensity ; and that the closest approximation to equa- 
lity was found in the mean intensities of the three sections 
of the lower deck. 
By comparing the mean intensities of the starboard and 
larboard sections of the upper deck, when the vessel was 
moored due north, it will be perceived that the results are 
precisely the same. This equality, however, will be found 
no longer to exist in the eastern and north-western positions 
of the ship, the larboard section having the ascendancy in 
the former situation of the vessel, and the starboard section 
in the latter. On the lower deck also, and when the ship's 
head was north, the difference between the mean intensities 
of the two lateral sections was 3.94 ; but when the vessel 
was moored easterly, this difference was increased to 18.44; 
and when north-westerly, it became 14-94 ; the excess being 
found on the starboard side in the former position, and on 
the larboard side in the latter. 
Some remarkable inferences may also be drawn from a 
comparison of the intensities of the upper and lower decks, 
