FLYING AND FLYING-MACHINES. 323 



to bear on the subject of the actual feasibility of 

 flying. 



In the problem of aerial navigation, four chief 

 points have to be considered buoyancy, extent of 

 supporting surface, propulsive power, and elevating 

 power. At first sight, buoyancy may seem to include 

 elevating power and supporting power, but it will be 

 seen, as we proceed, that the term is used in a more re- 

 stricted sense. 



In the balloon we have the perfect solution of the 

 problem of securing buoyancy. The success with 

 which men have overcome the difficulty of rising into 

 the air is complete ; and this being their first, and 

 seemingly, a most important success, we can perhaps 

 hardly wonder that further success should long have 

 been looked for in the same direction. The balloon 

 had enabled men to float in the air ; why should it 

 not enable them also to direct their course through the 

 air ? The difficulty of rising into the air seemed, 

 indeed, much the more serious of the two before the 

 balloon had been invented ; and all who had failed 

 in their attempts to fly, had failed in precisely this 

 point. 



Yet all attempts to direct balloons have hitherto 

 failed. It seems clear, indeed, when we inquire care- 

 fully into the circumstances of the case that such 

 attempts must necessarily fail. The buoyancy of bal- 

 loons is secured, and can be secured, only by one 

 method, and that method is such as to preclude all 

 possibility so at least it seems to me that the 



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