distribution , &c. of the magnetic intensity in ships of war. 325 
fourteen stations, A, B, C, &c. ; a, b, c, &c. were obtained, 
as nearly equidistant from each other, as circumstances would 
allow. 
The station © denotes the position of the binnacle, and on 
each side of it were the centres A, A' of the two compasses 
at the distance of ten inches. From the point © as a centre, 
two concentric circles were described on the deck, the ex- 
terior having a radius of six feet, and the interior of three 
feet. Each circumference was divided into twelve equal parts 
at the points, 1, 1', 2, 2', 3, 3 \ 4, 4', &c. ; and at these sta- 
tions, as well as at those before referred to, in the middle, 
starboard, and larboard sections, the mean intensity, by six 
sets of experiments, was determined by the same instrument 
and with the same precautions as described for the Scylla. 
In the middle line of stations an increase of intensity was 
perceptible from a to S, at the former station it being 102.19, 
and at the latter 121.87 ; but from the last mentioned station 
to £ , the intensity declined, after which it increased to £, where 
it became 125.18. In the starboard and larboard sections, 
the intensities at the stations A, a, were found to be much 
greater than that at the station « in the middle section, on 
account of the proximity of those stations to the bulk heads 
formed in the quarters of the ship. At B and b, the decline 
of intensity was found to be considerable ; but at the stations 
C, c, D, d, it was again augmented by the action of the car- 
ronades at the two after ports. At E, e, F ,/, a still greater 
increase was observed, produced in part by the carronades 
at the ports opposite the last mentioned stations. The carro- 
nades were trained parallel to the side of the ship, and in no 
case nearer than four feet to the instrument. Those opposite 
the stations F, /, were at a greater distance ; and hence it 
