4 
POPULAE SCIENCE EEVIEW. 
same time that the sharp-bowed vessel (fig. 8) had been 
pushed through the water the length of her bow, c x (fig. 9). 
The gain, therefore, in progression from form only to the 
sharp vessel would have been the difference of the length of 
her bow over that of her antagonist. 
Fig. 7. Fig. 8. 
Having ascertained the exact curve of the wave of water 
resistance to a given rate of motion, Mr. Scott Eussell reversed 
this for the bow line of his ship ; and while driving the vessel 
thus constructed at the rate of seventeen miles an hour, 
he placed two oranges in front of her. AYhen her bow 
passed between them the oranges rolled close alongside the 
whole way to the midships ; thus showing that the true 
‘‘ wave-line for this rate of speed had been attained, and 
that no greater force had been applied than was necessary 
to move them out of the way of the vessel. Against a non- 
coincident curved bow, or a straight one, the oranges would 
have struck and re-struck many times before reaching the 
widest part amidships. 
Now, if with the same rate of speed the same line of form 
could be maintained in all weathers, nothing could surpass 
the properties of wave-line vessels. But with every roll and 
lurch in ordinary as well as in wave-line steamers, the actual 
lines of form passed through the water deviate from the true 
luave-lines in proportion to the amounts of lateral and longi- 
tudinal movements of the vessel, and frictional resistance pro- 
portionate to these deviations is set up. When we state that 
the resistance to a square foot of plane surface, moved at six 
feet depth at eight knots an hour, has been proved by ex- 
periment to be 196*245 lb., and that moved at higher velocities, 
the resistance would be as the square of the increased velocity, 
the immense value of the form of a ship in respect to the 
attainment of speed will be appreciated. 
In regularity and equalness of lines actually passed through 
the water, under all the varying obstructions to which navig- 
able vessels are subjected, the cigar ship ” will undoubtedly 
be superior to every other; and for equality of length of 
voyages will, as undoubtedly, be remarkable. But whether 
fusiform or spindle-shaped ships will be able with the same 
amount of steam-power to obtain the same amount of speed as 
the wave-line boats in smooth water, may be doubted. 
But let us see what the cigar-ship ” is like. We give her 
portrait in Plate I. 
