EXTEAOEDmAEY SHIPS. 
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tMs wave will vary witli the sharpness or hhmtness of the object 
causing it_, as also with the rate at which it is moving. Now^ 
if the form of the vessel be made coincident with that of the 
wave thrown up by her passage_, it is evident that the greatest 
amount of bulk of hnll^ and the longest distance of progress, 
will be obtained compatible with the least amount of friction 
and resistance in the water through which it moves. This was 
Mr. Scott RnsselTs idea, and from his elaborate and costly ex- 
periments have resulted those beautiful, we might well call 
them exquisite, hues upon which the fleetest steamers in the 
world have been modelled. Let us see what the ‘"^wave line"’^ 
means. Steam power being equal, if the long bow could be 
pushed for its entire length through the water in the same time 
that it took to force the short bluff bow through for its length, 
the greatest amount of worh id oulcl he clone ivith the least loossihle 
amount of resistance. Now, what happens when a vessel goes 
through the water ? Her stem strikes against the particles 
of water and drives them off by the impetus of her motion 
at a right angle. By the old round-bowed vessels the particles 
of water were smashed off to the distance of the extreme 
width of the vessel in the shortest possible time. In the long, 
sharp-bowed vessel they are pushed aside proportionally in 
the longest possible time as the bows are more and more 
acute. 
rig. 5.— Action of Bluff Bow on Water. Fig. 6. — Action of Sharp Bow on Water. 
Let the dots a 5 be the particles of water first struck by the 
stem of an old bluff bow; they would respectively have to 
travel laterally from x up to the lines of extreme width of the 
ship, mf m! f , while the head of the midship portion m pro- 
gressed from m to f; while, with a vessel with the sharp bow 
(fig. 6), moving at the same rate, the like particles first 
struck, c d, would only have been pushed to g in the time the 
ship was progressing from m to g. In other words, the 
steam-power being the same, the bluff vessel (fig\ 7) would 
have been forced through the length of her bow, c x, in the 
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