31 B Mr. Harvey's experimental inquiries relative to the 
and decreased by the quantity 1.66 when her head bore 
north-west. It also appears from the same table, that the 
alterations of intensity are the least in the middle section, 
and greatest in the starboard section. In the two lateral sec- 
tions also it is the greatest when the ship's head was east, 
and in the middle section when it was north-west. 
The following table also illustrates the changes of inten- 
sity which each line of stations on the respective decks under- 
went as the ship passed from one situation to the other. 
Thus, in the third column, the degree of diminutions which 
the mean intensity of the starboard section underwent as the 
head of the ship passed from north to east, amounted to 
5.28 ; and as it’s head passed from north to north-west, the 
increase was 4.21. It also appears from an inspection of the 
same table, that with the exception of the middle section on 
the upper deck, the changes of intensity were the greatest 
in the transition of the ship from north to east. The vari- 
ations of intensity of the lower deck likewise much exceed 
those of the upper. 
Upper Deck. 
Change of Position 
of the Ship’s Head. 
Larboard 
Section. 
Middle 
Section. 
Starboard 
Section. 
Mean of the 
three Sections. 
From North 
to East, 
+ 2.39 
+ 1.92 
— 5.28 
— 0.32 
From North to 
North-west, 
+ 1.04 
+ 2.01 
+ 4-21 
+ 2.43 
Lower Deck. 
From North to 
East 
— 11.51 
4- 4.60 
-f 10.87 
+ .032 
From North to 
North-west, 
+ 7-57 
+ °-47 
— 3-43 
+ 1-53 j 
1 
