1874.] Loss of Life at Sea. 473 
high or low, whether the body had one keel or a dozen, 
small or large ; and this, because there is no motion of the 
particles of water amongst themselves, nor of the floating 
body amongst them, other than those produced by the one 
power ; they all being moved by the same power at the same 
time, and to the due extent, according to their relative 
positions in the orbit of motion, the upper parts or particles 
moving in the least arcs, though their motions may be 
modified by the law of gravitation; yet every one of the 
above changes in form, in weight, and in disposition of the 
weights, would affect the motions of a ship in a seaway in 
facilitating or in retarding motion, so that a ship’s motions 
could not synchronise with those of the wave. Moreover, 
as the motions of the water in his illustration are different 
from those of water in wave motion, in which the upper 
parts or particles moving with greater velocity than the 
lower, there is no analogy to the conditions of the water in 
the dish ; also as the parts of a ship are substantially rigid, 
and one part occupying space amongst the fast-moving 
particles, and another part amongst the slow-moving 
particles, it is impossible that the ship could move wholly 
with either one set or the other, or with both more than in 
part, and in some varying degree. Again, while in his 
illustration the containing vessel, the sea, the floating body, 
and all the water are moving together under the impulse of 
the centrifugal force; in the case of a ship at sea there is a 
portion of every ship that is down amongst the unagitated 
water, below wave motion; this portion of the body would 
resist and retard motion, and prevent a ship from accepting 
and moving. with the waves, if otherwise free or disposed 
to retain her masts perpendicular, to the slope of the wave. 
Indeed, were it true we should not have any such cases as 
ships and boats being rolled over by waves, which are only 
too numerous, and will be more so in proportion as his ideas 
on that subject are adopted. 
In fact in no case are the circumstances of a ship amongst 
waves similar to those of the illustrative model, nor can a 
ship ever ‘“‘ accept the aggregate dynamic conditions of the 
sea on which she floats,” nor still less ‘‘be treated” with 
any regard to truth ‘‘ as a surface particle of the wave on 
which she floats.” 
There are also further limitations on the motions of a 
ship in a seaway, to which the model in Mr. Froude’s 
illustration is not subject. 
Thus the amount of a ship’s motions are the result of the 
wind on the sails, or on the hull and masts, or the inertia 
