distribution , &c. of the magnetic intensity in ships of war. 35 1 
From an inspection of the preceding results it appears, 
that in passing from the mean intensity of the poop, to that 
of the quarter deck and forecastle, there is a decrease amount- 
ing to 2.42 ; from the deck last mentioned to the main deck, 
a feeble increase of 0.03 ; from the main to the middle deck, 
a diminution of 4.43 ; from the middle to the lower deck, an 
increase of 4.59 ; from that to the orlop deck, a decrement 
of 6.88; from the orlop deck to the hold, another decrement 
of 0.09 ; and from the mean intensity of the hold to the single 
intensity determined on the kelson, an increment of 14 . 63 . 
Hence it appears, that the greatest mean intensities are found 
at the extremes of the series ; that the mean results of the 
quarter deck and forecastle, and main and lower decks, 
are very nearly the same ; as are also those of the orlop 
deck and hold. The mean intensity of the middle deck is 
also very nearly a mean, between the mean of the intensi- 
ties of the three first mentioned decks, and of the two 
latter. The mean of the deck from the poop to the middle 
deck inclusive, is 98.71 ; and of the lower and orlop decks, 
hold and kelson 97 . 84 . The mean of all the decks is 98 . 28 , 
being 1.72 less than the assumed terrestrial intensity. 
In taking the means of the lines of stations vertically, it 
will be perceived, that the maximum intensity is attained at 
the line of stations denoted by H, and the minimum at the 
adjacent stations G. If also the mean of the middle column 
of intensities E be adopted, the result will be very nearly 
the same as the mean of the intensities of the middle deck ; 
and likewise, that the mean of the results of the columns 
A, B, C, D, abaft the column E, is very nearly equal to that 
of the columns F, G, H, I, on its other side ; the former 
