2l8 
Mr. Atwood's Disquisition on 
CASE II. 
The sides of a vessel project outward above the water-line* 
and are parallel to the masts under the water-line. 
The line B A (fig. 4.) represents the intersection of the 
water's surface with the vessel, when floating upright. The 
lines PC, QW, are parallel to each other, and to the line XO, 
which coincides with the plane of the masts, and bisects the line 
BA in the point D ; B C and AW, which are parallel to the 
plane of the masts, coincide with the sides of the vessel under 
the water-line ; and BY, AH, which project outwards from 
the plane of the masts, at the angle QAH, or YBP, are the 
sides of the vessel above the water-line. C H represents the 
intersection of the water's surface with the vessel, when in- 
clined from the perpendicular, through a given angle OPQ = 
ASH. The distance G E, between the centres of gravity of 
the vessel and of the volume displaced, and the magnitude of 
that volume being supposed known, and the angle QAH, at 
which the sides AH, BY, are inclined to the plane of the masts, 
being also known, it is required to ascertain, by geometrical 
construction, the measure of the vessel's stability, when the 
which is exactly equal to the force to be applied for that purpose. Another method 
of inclining a vessel (well adapted for making experiments on this subject) is, by ap- 
plying a timber at right angles to the plane of the masts. If a weight be affixed to 
one of its extremities, from having given the weight so applied, and its distance from 
the plane of the masts, together with the other conditions which determine stability, 
the angle of inclination, through which the ship will be inclined, may be determined; 
by the theorems in these pages. The same inferences may be obtained, from having 
given the weights and spaces through which the guns are run out on one side, and 
drawn in on the Other* instead of the weight affixed, according to the method last 
described. 
