478 Loss of Life at Sea. (October, 
the water has partially left the other side, decreasing the 
pressure there and lowering the puint to £. These two 
pressures act as a couple to rotate the ship; that at p high 
up, and more high as the wave is higher and its upper par- 
ticles moving with greater velocity. That at ps low and more 
low as the hollow of the wave is deeper, and their power to 
rotate the ship increases in the same extent. 
Then Pp’, moved over to the side of greater pressure, acts 
up on a line normal to the earth and perpendicular to the 
mean level of the sea through ¢; G in the first instance 
representing the position of the centre of gravity, and G¢ the 
perpendicular distance from the line of pressure; this also 
tends to turn the ship in the same direction as the other 
pressures. 
It is clear that the greater is the accumulation of water 
the further p’ will be carried over, and the greater will be 
the lever Gt, which in this case tends to overset; con- 
sequently, any arrangements that would tend to increase 
this accumulation of water would be injurious, and might be 
dangerous. 
Now suppose the centre of gravity lowered to a’,, then 
the upsetting lever will be G’#’, which is obviously shorter 
than Gt; consequently, lowering the centre of gravity 
reduces the power of the wave to incline or roll the ship, and 
tends to limit the arcs rolled through. 
Or suppose, though it is less accurate, these three forces 
to be represented by one at P passing up through the 
centre of figure c’. In Fig. 2, it is clear that the greater 
is the accumulation, the greater distance c’ will be moved 
out from a line passing through the middle of se¢tion or 
ship; therefore the greater will be the distances of a per- 
pendicular to the earth passing through c’ from the centres 
of gravity at G or at G’: obviously, as in the former case, 
in proportion as the centre of gravity G is lowered, so the 
disturbing lever is decreased. 
It is clear also that the greater is the breadth, the greater 
distance will c’ be carried out, and the greater will be the 
disturbing lever. 
The greater is the accumulation of water also, the further 
is c’ carried out, and the greater is the disturbing lever. 
The greater is the effect of Mr. Froude’s recommendations, 
the greater becomes the upsetting lever. 
The higher also the centre of gravity is, the longer is the 
disturbing lever, and the greater is the extent of the motions 
and danger of upsetting. (See p. 490 for a more definite 
proof.) 
