8 
POPULAR SCIENCE REVIEW. 
difference of leverage^ the see-saw will not be a pleasant game. 
So with an ordinary vessel, there are oscillating dead weights 
at each end, and if the weights of engine and cargo are not 
placed trim,^^ so as by their inertia to bring the fulcrum 
which the sea gives to the vessel in her longitudinal movements 
in the proper place, she will be an uneasy vessel. As there 
is always a difference of weight and displacement between the 
bows and stern of an ordinary ship, the dead weight of engines 
and cargo must be so placed as to bring the fulcrum of water 
under the vessel at that point upon each side of which the 
weight of the bows and the stern, by reason of increased or 
diminished leverage, are equally balanced, — not an easy thing 
to do. It is evident, on the other hand, that the hollow 
spindle, having its greatest cubic capacity directly in the centre, 
will have there the greatest weight of engine and cargo ; that 
also every part being buoyant, there will be no dead weights 
oscillating at either equal or unequal leverages ; and that there 
would be but little pitching and '’scending even if the vessel 
were bodily hfted by a large high wave, for the greatest weight of 
the ship being in the 
centre of her length 
(at m) would possess 
a massiveness there 
incompatible with 
any lengthened os- 
cillations of her light 
and buoyant extre- 
mities (u, d). It is likely the ^‘^cigar-ship,^^ from her length and 
the fineness of her lines, may strike right through a sea ; but if 
she does her deck is raised over the highest point of the 
central and biggest portion of the spindle, and well protected 
with bulwarks. 
That which strikes one as most likely to happen, and most 
awkward if it did, is that the spindle-form hull seems uncom- 
monly likely to roll round; and, 
indeed, the raised deck and smoke 
funnels look as if in lurching they 
would pull her over and form an 
unintentional keel to keep her 
wrong side up. A very little me- 
chanical knowledge will soon, how- 
ever, satisfy one that such an accident 
cannot well occur. In the first 
place, the under-plates of the hull 
are ~ inch thick, and strengthened by 
an outer plate 1 inch in thickness ; 
while the upper skin-plates are -fV or half the thickness. 
Fip. 17. — Section of Hull, showing 
Thickness of Plates of Skin above 
and below the Water-line. 
