448 Mr. G. Walker on the Theory of a 



If the theory be sound, it will not be so in vain ; and how- 

 ever difficult, and perhaps remote its application may be, yet 

 human ingenuity at length overcomes mere practical difficul- 

 ties, and realizes the use of every great general principle in 

 Nature, at their appointed time, to meet the extended wants 

 of advancing civilization. 



The ocean, bearing its heavy burdens from any one shore 

 to every other by wind and tide, and lately by steam, has 

 hitherto been the great means both of civilization and wealth; 

 but the resistance of water to vessels increasing in the enor- 

 mous ratio of the squares of their velocities, has placed a limit 

 to steam-boat speed, which can only be exceeded by an un re- 

 munerative expense of steam power: and even this is not by 

 any means the limit of the barrier that has to be overcome ; 

 for every increase of speed in the vessel requires an equal in- 

 crease of swiftness in the paddles to overtake it, which causes 

 the steam power expended to be in the ratio of the cubes of 

 the velocities of the vessel. Thus double the speed requires 

 eight times the power, and three times the speed requires 

 twenty-seven times the power. There is no principle in nature 

 yet known to modify this rapidlyaccurnulating lawof resistance, 

 but that of increasing the magnitude of our vessels to as great 

 an extent as their materials will safely permit ; for the resist- 

 ances will vary as the surfaces of the prows of the vessels, and 

 these are as the squares of any homologous dimensions ; 

 whereas the engine power any vessel can carry is as its solid 

 contents, and these are as the cubes of such homologous parts : 

 hence if any vessel be double the size of another, its resistance 

 will be only fourfold greater at any given velocity, but its 

 floatage to carry engine power will be eightfold. 



We have here all the elements of steam-boat navigation as 

 it now stands ; and it seems probable that from eighteen to 

 twenty miles per hour, at great cost, may be a tolerably ap- 

 proximate limit of speed, under every advantage our know- 

 ledge of engine power and ship-building materials can com- 

 mand ; and a most astonishing triumph of mechanical skill 

 over natural impediments it is to have attained to this speed. 



The law of resistance in water is the great obstacle that 

 causes this enormous consumption of power ; and if it can be 

 shown that there exists in nature a mechanical principle ca- 

 pable of reducing this expense to one-fortieth part of its pre- 

 sent scale, its physical and moral value need scarcely be 

 pointed out ; it would extend our railroad speed over the 

 ocean without the cost of its iron way, and this in every pos- 

 sible direction within the command of a sea-girt world. Who 

 can scan the future results of such an increased power of com- 



